2000
		Niwot Ridge/Green Lakes Valley Site Bibliography

	The entries appended below represent the Niwot Ridge LTER site 
bibliography in its entirety. The descriptor NWTLTER identifies entries that 
were at least partially supported by the Niwot Ridge Long-Term Ecological 
Research program. Each bibliographic entry is separated from adjacent entries 
by the '$' character and contains the following fields:
	
	CL unique identification number for each record
	AU author(s)
	DT year of publication
	TI title of publication
	SO source (e.g., journal, book, etc.)
	DE descriptor(s) (i.e., keywords)
	AB abstract ("None" indicates that the abstract has not 
                yet been incorporated into the database)



$
CL1469
AU Ackerman, T.M.
; Erickson, T.
; Williams, M.W.
DT 2001
TI Combining GIS and GPS to improve our understanding of the spatial distribution of snow water equivalence (SWE)
SO Proceedings, ESRI user conference, San Diego, California
DE GIS
; GPS
; SWE
; NWTLTER
AB An overarching concern in snow hydrology is the spatial distribution of snow water equivalence (SWE). Our ability to utilize spatially distributed models of snowmelt and runoff is limited by our ability to adequately characterize the spatial distribution of SWE. We will present a study of an alpine basin in Colorado for which a DEM is available and the major landscape types have been mapped and digitized onto a GIS. Using a combination of field measurements and geostatistical techniques we have estimated the distribution of snow water equivalent throughout the basin and compared it to the mapped landscape types, to investigate the relationship of snow water equivalent to landcover type, slope, and aspect. $
CL 1349
AU Addington, R.N.
; Seastedt, T.R.
DT 1999
TI Activity of soil microarthropods beneath snowpack in alpine tundra and subalpine forest
SO Pedobiologia 43:47-53
DE NWTLTER
; alpine
; microarthropods
; soil temperature
; subnivean
; winter activity
AB The activity of soil microarthropods during winter were studied in alpine tundra 
 and subalpine forest ecosystems in the Front Range of Colorado, USA. Microarthropods 
 were collected in pitfall traps from soils beneath shallow and deep snowpack to 
 assess the effect of soil surface temperature on activity in these respective 
 ecosystems. Overall, microarthropod activity was positively correlated with soil 
 surface temperature; pitfall collections with greater numbers of microarthropods 
 were correlated with higher temperatures. However, this relationship was less evident 
 in the alpine tundra than in the subalpine forest, suggesting that microarthropods 
 were less sensitive to the range of temperature observed here. Results indicate that
 microarthropods beneath snowpack in alpine tundra are as active as those observed 
 in the subalpine forest, and that microarthropod activity in these ecosystems should 
 be enhanced by increases in winter precipitation.
$
CL 0000b
AU Albritton, D.L.
DT 1984
TI Atmospheric sampling program
SO In: Aeronomy Laboratory Annual Report - Fiscal Year 1984. Boulder, Colorado:
 Department of Commerce, National Oceanic and Atmospheric Administration,
 Environmental Research Laboratories, 18-29
DE Technical Report
; Atmospheric Sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0000c
AU Albritton, D.L.
DT 1985
TI Atmospheric sampling program
SO In: Aeronomy Laboratory Annual Report - Fiscal Year 1985. Boulder, Colorado:
 Department of Commerce, National Oceanic and Atmospheric Administration,
 Environmental Research Laboratories, 1-22
DE Technical Report
; Atmospheric Sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$CL 0000a
AU Albritton, D.L.
DT 1983
TI Atmospheric sampling program
SO In: Aeronomy Laboratory Annual Report - Fiscal Year 1983. Boulder, Colorado:
 Department of Commerce, National Oceanic and Atmospheric Administration,
 Environmental Research Laboratories, 17-35
DE Technical Report
; Atmospheric Sciences
; NOAA -  Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0003
AU Alexander, G.
DT 1951
TI The occurrence of Orthoptera at high altitudes, with special reference to
 Colorado Acrididae
SO Ecology, 32:104-112. Reprinted in: Ives, J.D. (ed.), 1980:Geoecology of the
 Colorado Front Range. Boulder: Westview Press, 448-459
DE Ecology
; University of Colorado
; Indian Peaks region
; Niwot Ridge
; Insects
; Altitude
; Distribution
; Movement
AB None
$
CL 0007
AU Alexander, G.
; Hillard, J.R., Jr.
DT 1969
TI Altitudinal and seasonal distribution of Orthoptera in the Rocky Mountains
 of northern Colorado
SO Ecological Monographs, 39:385-431
DE Ecology
; University of Colorado
; Niwot Ridge
; Insects
; Altitude
; Distribution
; Phenological (seasonal)
AB None
$
CL 0009
AU Alford, D.
DT 1973
TI Cirque glaciers of the Colorado Front Range: Mesoscale aspects of a glacier
 environment
SO Ph.D. dissertation, University of Colorado, Boulder. 198 pp.
DE Dissertation
; Climatology
; Glaciology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Altitude
; Insolation
; Snow
; Wind
AB None
$
CL 0021
AU Andrews, J.T.
; Webber, P.J.
; Thorn, C.E.
; LeDrew, E.
DT 1973
TI Tundra environment on Niwot Ridge, Colorado Front Range. Guide for Field
 Trip No. 7, 26th Annual Meeting, Rocky Mountain Section
SO Geological Society of America. Boulder, University of Colorado. 31 pp.
DE Guide
; Climatology
; Ecology
; Geoecology
; Geology
; Institute of Arctic and Alpine Research
; Niwot Ridge
AB None
$
CL 0020
AU Andrews, J.T.
; Nichols, H.
; Short, S.K.
; Stuckenrath, R.
; Birkeland, P.W.
DT 1982
TI Alpine lake-sediment studies, Front Range Colorado: a contribution to the
 Long-Term Ecological Research (LTER) Program
SO American Quaternary Association, Seventh Biennial Conference, Program and
 Abstracts, p. 61. Abstract
DE Abstract
; Paleoecology
; Sedimentology
; Institute of Arctic and Alpine Research
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Bryophytes
; Tracheophytes
; Altitude
; Community
; Succession
; Pollen
; Lake
; Sediment
AB None
$
CL 0016a
AU Andrews, J.T.
; Birkeland, P.W.
; Harbor, J.
; Dellamonte, N.
; Litaor, M.
; Kihl, R.
DT 1985
TI Holocene sediment record, Blue Lake, Colorado Front Range
SO Zeitschrift fur Gletscherkunde und Glazialgeologie, 21:25-34
DE Sedimentology
; Paleoecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Dating - Radiocarbon and Other
; Lake
; Sediment
; Watershed
; Wind
; NWTLTER
AB None
$
CL 0017
AU Andrews, J.T.
; Birkeland, P.W.
; Kihl, R.
; Litaor, M.
; Nichols, H.
; Stuckenrath, H.
DT 1982
TI Holocene lake sediments from subalpine and alpine lakes, Colorado Front
 Range: baseline studies.  
SO Geological Society of America, Abstracts, 14:433.
 Abstract
DE Abstract
; Geology
; Glaciology
; Sedimentology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Lake
; Watershed
; Sediment
; Long Term Ecological Research Program
AB None
$
CL 1376
AU Arft, A.M.
; Walker, M.D.
; Gurevitch, J.
; Alatalo, J.M.
; Bret-Harte, M.S.
; Dale, M.
; Diemer, M.
; Gugerli, F.
; Henry, G.H.R.
; Jones, M.H.
; Hollister, R.D.
; Jonsdottir, I.S.
; Laine, K.
; Levesque, E.
; Marion, G.M.
; Molau, U.
; Molgaard, P.
; Nordenhall, U.
; Raszhivin, V.
; Robinson, C.H.
; Starr, G.
; Stenstrom, A.
; Stenstrom, M.
; Totland, O.
; Turner, P.L.
; Walker, L.J.
; Webber, P.J.
; Welker, J.M.
; Wookey, P.A.
DT 1999
TI Responses of tundra plants to experimental warming: Meta-analysis of the
 international tundra experiment
SO Ecological Monographs 69:491-511
DE NWTLTER
; arctic tundra
; experimental warming
; global change
; global warmings
; International Tundra Experiment
; ITEX
; meta-analysis
; plant response patterns
; spatiotemporal gradients
; tundra plants
AB The International Tundra Experiment (ITEX) is a c
2000
ollaborative, multisite 
 experiment using a common temperature manipulation to examine variability 
 in pecies response across climatic and geographic gradients of tundra ecosystems.  
 ITEX was designed specifically to examine variability in arctic and alpine 
 species response to increased temperaure.  We compiled from one to four years 
 of experimental data from 13 different ITEX sites and used meta-analysis to 
 analyse responses of plant phenology, growth, and reproduction to experimental 
 warming. Results indicate that key phenological events such as leaf bud burst 
 and flowering occurredearlier in warmed plots throughout the study period; 
 however, there was little impact on growth cessation at the end of the season.  
 Quantitative measures of vegetative groth were greatest in warmed plots in the 
 early years of the experiment, whereas reproductive effort and success increased 
 in later years. A shift away from vegetative growth and toward reproductive effort 
 and success in the fourth treatment year suggests a shift from the initial response 
 to a secondary response. The change in vegetative response may be due to depletion 
 of stored plant reserves, whereas the lag in reproductive response may be due to 
 the formation of flower buds one to several seasons prior to flowering.  Both 
 vegetative and reproductive responses varied among life-forms; herbaceous forms 
 had stronger and more consistent vegetative growth responses than did woody forms.  
 The greater responsiveness of the herbaceous forms may be attributed to their 
 more flexible morphology and to their relatively greater proportion of stored 
 plant reserves.  Finally, warmer, low arctioc sites produced the strongest 
 growth responses, but colder sites produced a greater reproductive response.  
 Greater resource
 investment in vegetative growth may be a concervative strategy in the Low Arctic, 
 where there is more competition for light, nutrients, or water, and there may 
 be little oppurtunity for successful germination or seedling development. 
 In contrast, in the High arctic, heavy investment in producing seed under a 
 higher temperature scenario may provide an oppurtunity for species to colonize 
 patches of unvegetated ground.  The observed differential response to warming 
 suggests that the primary forces driving the response vary across climatic zones, 
 functional groups, and through time. 
$
CL 1435
AU Armstrong, D.M. 
; Halfpenny, J.C.
; Southwick, C.H.
DT 2001
TI Vertebrates
SO Chapter 7 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 1313
AU Asner, G.P.
; Seastedt, T.R.
; Townsend, A.R.
DT 1997
TI The decoupling of terrestrial carbon and nitrogen cycles
SO BioScience 47(4):226-234
DE NWTLTER
; nitrogen cycle
; carbon cycle
; land use
AB None
$
CL 0024b
AU Auerbach, N.A.
; Halfpenny, J.C.
DT 1987
TI Snow course data for North Boulder Creek drainage, Front Range, Colorado
 1938-1986
SO University of Colorado Long-Term Ecological Research Data Report 87/2. 15 pp
DE Data Report
; Hydrology
; Long-Term Ecological Research Program
; Soil Conservation Service
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0024a
AU Auerbach, N.A.
; Halfpenny, J.C.
DT 1986
TI Weather perspective for the first six years of University of Colorado
 Long-Term Ecological Research, Saddle Climate Station, Niwot Ridge, Colorado
 1981 - 1986
SO University of Colorado Long-Term Ecological Research Data Report 86/3. 13 pp
DE Data Report
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Climate - Data Included
; Climate - Discussion of
; Snow
; Temperature
; Wind
AB None
$
CL 0024c
AU Auerbach, N.A.
; Halfpenny, J.C.
; Taylor, M.D.
DT 1987
TI Ecological data on small mammal hervibores from the Colorado alpine tundra
 1984-1987
SO University of Colorado Long-Term Ecological Research Data Report 87/9. 67 pp
DE Data Report
; Ecology
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Animals
; Rodents
; Lagomorphs
; Technique
; Demography
; Population
; Productivity
; Reproduction
AB None
$
CL 1408
AU Aydellote, A.
DT 1996
TI Developmental preformation and phenotypic plasticity in the alpine herb 
   Caltha leptosepala
SO M.S. Thesis, University of Colorado, Boulder. 74 pp.
DE None
AB None
$
CL 1330
AU Aydelotte, A.R.
; Diggle, P.K.
DT 1997
TI Analysis of developmental preformation in the alpine herb Caltha
 leptosepala (Ranunculacaea). 
SO American Jounal of Botany 84: 1646-1657
DE NWTLTER
; Caltha leposepala
; development
; preformation
AB None
$
CL 0031
AU Barber, R.A.
DT 1935
TI An ecological study of a small, montane, spring-fed stream area in the
 University of Colorado Camp, on Mount Niwot
SO M.A. thesis, University of Colorado, Boulder. 76 pp.
DE Thesis
; Ecology
; University of Colorado
; Mountain Research Station - Location
; Stream
AB None
$
CL1460
AU Baron, J.S.
; Rueth, H.M.
; Wolfe, A.M.
; Nydick, K.R.
; Allstott, E.J.
; Minear, J.T.
; Moraska, B.
DT 2000
TI Ecosystem responses to nitrogen deposition in the Colorado Front Range
SO Ecosystems 3:352-368
DE NWTLTER
AB None
$
CL 1371
AU Baron, J.S.
; Caine, N.
DT 2000
TI Temporal coherence of two alpine lake basins of the Colorado
 Front Range, U.S.A
SO Freshwater Biology 43:463-476
DE NWTLTER
; alpine lake basins
; temporal coherence
; Colorado Front Range
AB 
$
CL 1262
AU Baron, J.S.
; Ojima, D.S.
; Holland, E.A.
; Parton, W.J.
DT 1994
TI Analysis of nitrogen saturation potential in Rocky Mountain tundra
 and forest: Implications for aquatic systems
SO Biogeochemistry 27:61-82
DE NWTLTER
; alpine tundra
; aquatic ecosystems
; CENTURY model
; Colorado Rocky Mountains
; nitrogen saturation
; subalpine forest
AB We employed grass and forest versions of the CENTURY model under a
 range of N deposition values (0.02-1.60 g N/m^2/y) to explore the
 possibility that high observed lake and stream N was due to terrestrial
 N saturation of alpine tundra and subalpine forest in Loch Vale 
 Watershed, Rocky Mountain National Park, Colorado. Model results
 suggest that N is limiting to subalpine forest productivity, but that
 excess leachate from alpine tundra is sufficient to account for the
 current observed stream N. Tundra leachate, combined with N leached
 from exposed rock surfaces, produce high N loads in aquatic ecosystems
 above treeline in the Colorado Front Range. A combination of 
 terrestrial leaching, large N inputs from snowmelt, high watershed
 gradients, rapid hydrologic flushing and lake turnover times, and 
 possibly other nutrient limitations of aquatic organisms constrain
 high elevation lakes and streams from assimilating even small
 increases in atmospheric N. CENTURY model simulations further suggest
 that, while increased N deposition will worsen the situation, nitrogen
 saturation is an ongoing phenomenon.
$     
CL 1393 
AU Baron, J.S.
; Williams, M.W.
DT 2000
TI Preface, Recent Loch Vale Watershed Research
SO Water Resources Research 36(1):11-12
DE None
AB None
$
CL1546
AU Barry, R. 
; Seimon, A.
DT 2000
TI Research for mountain area development: Climatic fluctuations in the mountains of the Americas and their significance
SO AMBIO vol. 29 no. 7 pp. 364-370
DE NWTDATA
AB None
$
CL 0040
AU Barry, R.G.
; Clark, J.M.
DT 1975
TI Evaluation of an ERTS-1 data collection platform installed in the alpine
 tundra, Colorado
SO Journal of Applied Meteorology, 14:622-626
DE Climatology
; Remote sensing
; Institute of Arctic and Alpine Research
; Technique
AB None
$
CL 0033
AU Barry, R.G.
DT 1972
TI Climatic environment of the east slope of the Colorado Front Range
SO University of Colorado, Institute of Arctic and Alpine Research Occasional
 Paper, 3. 206 pp.
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Altitude
; Climate - Data Included
AB None
$
CL 0039
AU Barry, R.G.
DT 1985
TI Growing season temperature chara
2000
cteristics, Niwot Ridge and the east slope
 of the Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Data Report, 85/6.
 52pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; A-1 Climate Station
; Temperature
AB None
$
CL 0042
AU Barry, R.G.
; Van Wie, C.C.
DT 1974
TI Topo- and microclimatology in alpine area
SO In: Ives, J.D. and Barry, R.G. (eds.), Arctic and Alpine Environments.
 London: Methuen, 73-83
DE Climatology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Climate - Data Included
AB None
$
CL 0034
AU Barry, R.G.
DT 1973
TI A climatological transect on the east slope of the Front Range, Colorado
SO Arctic and Alpine Research, 5(2):89-110. Reprinted in: Ives, J.D.
 (ed.),1980, Geoecology of the Colorado Front Range. Boulder: Westview Press,
 264-285
DE Climatology
; Institute of Arctic and Alpine Research
; Altitude
; Climate - Data Included
; A-1 Climate Station
AB None
$
CL 0036
AU Barry, R.G.
DT 1980
TI Climatology: overview
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press. 259-263
DE Climatology
; Institute of Arctic and Alpine Research
AB None
$
CL 0036a
AU Barry, R.G.
DT 1987
TI Mountain climatology: status and prospects.
SO Ecological Bulletins 38:38-46.
DE article
; climatology
; University of Colorado
; A-1 to D-1
; climate - discussion of
AB None
$
CL 1208
AU Barry, R.G.
DT 1986
TI Mountain climate data for long-term ecological research
SO Pp 170-187 In: Proceedings of International Symposium on the Qinghai-Xizang
 Plateau and Mountain Meteorology. Beijing, China, 20-24 March 1984. Science
 Press: Beijing; American Meteorological Society: Boston
DE NWTLTER
; climatology
; precipitation
; temperature
; Niwot Ridge
; Berthoud Pass
AB None
$
CL 0041
AU Barry, R.G.
; LeDrew, E.F.
DT 1974
TI The energy budget of the alpine tundra, Colorado.
SO U.S. Tundra Biome Data Report, 74-2, 93 pp.
DE Data report
; Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Insolation
AB None
$
CL 0042a
AU Barsch, D.
; Caine N.
DT 1984
TI The nature of mountain geomorphology
SO Mountain Research and Development, 4:287-298
DE article
; geomorphology
; Long-Term Ecological Research Program
; Niwot Ridge
; Boulder City Watershed
; glacier
; lake
; stream
; landslide
; watershed
; water
AB None
$
CL 1515
AU Bechtold, H.A.
; Forbis, T.A
; Bowman, W.D. 
; Diggle, P.K.
DT 2002
TI Lack of reproductive plasticity in alpine Saxifraga rhomboidea Greene (Saxifragaceae)
SO Nordic Journal of Botany v. 22 pp. 361-368
DE NWTLTER
; SIMULATED ENVIRONMENTAL-CHANGE
; PHENOTYPIC PLASTICITY
; CLIMATE-CHANGE
; LIFE-HISTORY
; NUTRIENT AVAILABILITY
; TUNDRA COMMUNITIES
; PLANTS
; RESPONSES
; GROWTH
; PREFORMATION
AB Phenotypic plasticity is predicted to be highly advantageous to alpine plants because of the extreme spatial and temporal heterogeneity of the alpine environment. Alpine plants are constrained in their vegetative plasticity by developmental preformation, however, they have the potential for reproductive plasticity via abortion of reproductive structures. Saxifraga rhomboidea Greene (Saxifragaceae) is a perennial of alpine dry meadows. It lacks a mechanism for vegetative reproduction, therefore, seed production is particularly important in maintaining populations of this species. Using long-term fertilized plots at the Niwot Ridge Long-Term Ecological Research Site, we ask if fertilization has changed the abundance of S. rhomboidea, and if S. rhomboidea has shown a plastic reproductive response to nutrient additions. Despite a pronounced increase in community biomass, we found that abundance of S. rhomboidea was not affected by fertilization. Moreover, S. rhomboidea showed no plastic response in seed to ovule ratio or other reproductive measures. Other arctic and alpine species have shown the potential for plasticity of maternal investment; S. rhomboidea appears to lack this reproductive plasticity. We suggest that morphological constraints may limit plasticity in this species.
$
CL 0047
AU Becwar, M.R.
; Rajashekar, C.
; Hansen-Bristow, K.J.
; Burke, M.J.
DT 1981
TI Deep undercooling of tissue water and winter hardiness limitations in
 timberline flora
SO Plant Physiology, 68:111-114
DE Temperature
; Ecology
; Long-Term Ecological Research Program
; Conifers
; Altitude
; Physiological
; Metabolism
AB None
$
CL 0049
AU Behnke, R.J.
DT 1977
TI Evaluation of recent collections of cutthroat trout in Colorado
SO Report prepared for the Colorado Division of Wildlife, Denver. 18 pp.
DE Technical report
; Taxonomy & systematics
; Ecology
; Mountain Research Station - Location
; Fish
; Stream
AB None
$
CL 0048
AU Behnke, R.J.
DT 1976
TI Summary of information on the status of greenback cutthroat trout, Salmo
 clarki stomias
SO Report prepared for U.S. Fish and Wildlife Service, Salt Lake City Area
 office. 30 pp.
DE Technical report
; Taxonomy & systematics
; Ecology
; Mountain Research Station - Location
; Fish
; Stream
AB None
$
CL 0051
AU Bell, K.L.
DT 1974
TI Autumn, winter, and spring phenology of some Colorado alpine plants
SO American Midland Naturalist, 91:460-464
DE Ecology
; Meteorology
; Niwot Ridge
; Angiosperms
; Phenological (seasonal)
AB None
$
CL 0055
AU Benedict, J.B.
DT 1966
TI Radiocarbon dates from a stone-banked terrace in the Colorado Rocky
 Mountains, U.S.A.
SO Geografiska Annaler, 48A:24-31
DE Glaciology
; Geomorphology
; Chronology
; Dating - Radiocarbon and Other
; Niwot Ridge
; Institute of Arctic and Alpine Research
AB None
$
CL 0061
AU Benedict, J.B.
DT 1970
TI Frost cracking in the Colorado Front Range
SO Geografiska Annaler, 52A:87-93
DE Climatology
; Geomorphology
; Frost
; Permafrost
; Institute of Arctic and Alpine Research
AB None
$
CL 0069
AU Benedict, J.B.
DT 1984
TI Rates of tree-island migration, Colorado Rocky Mountains, USA
SO Ecology, 65(3):820-823
DE Ecology
; Niwot Ridge
; Conifers
; Tree
; Movement
AB None
$
CL 0072
AU Benedict, J.B.
; Olson, B.L.
DT 1978
TI The Mount Albion Complex: A Study of Prehistoric Man and the Altithermal
SO Ward, Colorado: Center for Mountain Archeology, Research Report No. 1. 213
 pp.
DE Archaeology
; Climatology
; Chronology
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0058
AU Benedict, J.B.
DT 1968
TI Recent glacial history of an alpine area in the Colorado Front Range, U.S.A.
 II. Dating the glacial deposits
SO Journal of Glaciology, 7(49):77-87
DE Geomorphology
; Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
; Periglacial
; Institute of Arctic and Alpine Research
; Lichens
AB None
$
CL 0066
AU Benedict, J.B.
DT 1979
TI Getting away from it all: a study of man, mountains, and the two-drought
 altithermal
SO Southwestern Lore, 45(3):1-12
DE Archaeology
; Paleoecology
; Boulder Watershed and Rainbow Lakes
; Chronology
AB None
$
CL 0065
AU Benedict, J.B.
DT 1975
TI Scratching deer: a late prehistoric campsite in the Green Lakes Valley,
 Colorado
SO Plains Anthropologist, 20(70):267-280
DE Archaeology
; Paleoecology
; Boulder Watershed and Rainbow Lakes
; Chronology
AB None
$
CL 0062
AU Benedict, J.B.
DT 1973
TI Chronology of cirque glaciation, Colorado Front Range
SO Quaternary Research, 3:584-599
DE Geomorphology
; Glaciology
; Chronology
; Glacier
AB None
$
CL 0070b
AU Benedict, J.B.
; Benedict, R.J.
; Sanville, D.
DT 1986
TI Arapaho Rock Glacier, Front Range, Colorado, USA: a 25-year resurvey
SO Arctic and Alpine Research, 18(3):349-352
DE Journal
; Geomorphology
; Boulder Watershed and Rainbow Lakes
; Stratigraphy
; Geology
; Indian Peaks Region
; Periglacial
AB None
$
CL 0064
AU Benedict, J.B.
DT 1975
TI The Albion Boardinghouse site: archaic occupation of a high mountain valley
SO Southwestern Lore, 41(3):1-12
DE Archaeology
; Paleoecology
; Boulder Watershed and Rainbow Lakes
; Chronology
AB None
$
CL 0056
AU Benedict, J.B.
DT
2000
 1967
TI Recent glacial history of an alpine area in the Colorado Front Range, U.S.A.
 I. Establishing a lichen growth curve
SO Journal of Glaciology, 6(48):817-832
DE Glaciology
; Paleoecology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
; Growth (Development)
; Institute of Arctic and Alpine Research
; Lichens
AB None
$
CL 0060
AU Benedict, J.B.
DT 1970
TI Downslope soil movement in a Colorado alpine region: rates, processes, and
 climatic significance
SO Arctic and Alpine Research, 2(3):165-226. Reprinted in part in: Ives, J.D.
 (ed.), 1980: Geoecology of the Colorado Front Range. Boulder:  Westview Press,
 123-150
DE Climatology
; Geomorphology
; Sedimentology
; Management
; Soil sciences
; Institute of Arctic and Alpine Research
AB None
$
CL 0068
AU Benedict, J.B.
DT 1982
TI Soft-sediment deformation by rock glaciers, Indian Peaks Wilderness Area,
 Colorado Front Range
SO American Quaternary Association, Seventh Biennial Conference, Program and
 Abstracts, 68 Abstract
DE Abstract
; Geomorphology
; Glaciology
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0059
AU Benedict, J.B.
DT 1969
TI Microfabric of patterned ground
SO Arctic and Alpine Research, 1:45-48
DE Geomorphology
; Frost
; Niwot Ridge
; Permafrost
; Institute of Arctic and Alpine Research
; Periglacial
AB None
$
CL 0057
AU Benedict, J.B.
DT 1968
TI Neoglacial history of the Colorado Front Range
SO Ph.D. dissertation, University of Wisconsin. 75 pp.
DE Dissertation
; Climatology
; Paleoecology
; Chronology
; Geology
; Glaciology
; Boulder Watershed and Rainbow Lakes
; Glacier
; Institute of Arctic and Alpine Research
; Lichens
AB None
$
CL 0071
AU Benedict, J.B.
; Corte, A.E.
; Osburn, W.S.
DT 1965
TI Frost phenomena, patterned ground, and ecology on Niwot Ridge
SO In: Schultz, C.B. and Smith, H.T.U. (eds.), Guidebook for One-Day Field
 Conferences, Boulder Area, Colorado. International Association for Quaternary
 Research, VIIth Congress, 27-35
DE Guide
; Ecology
; Geomorphology
; Niwot Ridge
; Frost
; Permafrost
; Periglacial
AB None
$
CL 0063
AU Benedict, J.B.
DT 1974
TI Early occupation of the Caribou Lake site, Colorado Front Range
SO Plains Anthropologist, 19(63):1-4
DE Archaeology
; Paleoecology
; Boulder Watershed and Rainbow Lakes
; Chronology
AB None
$
CL 0075A
AU Berg, N.H.
DT 1986
TI Blowing snow at a Colorado alpine site: measurements and implications
SO Arctic and Alpine Research, 18(2):147-161
DE Journal
; Geomorphology
; Hydrology
; Niwot Ridge
; Snow
; Wind
AB None
$
CL 0075
AU Berg, N.H.
DT 1976
TI Prediction of natural snowdrift accumulation on alpine sites
SO Ph.D. dissertation, University of Colorado, Boulder. Summarized in:
 Ives,J.D. (ed.), 1980: Geoecology of the Colorado Front Range Boulder:
 Westview Press, 254-258
DE Dissertation
; Hydrology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Snow
AB None
$
CL 0076
AU Bernstein, R.A.
DT 1974
TI Comparative worker size and reproductive output of subpopulations of the
 alpine ant, Formica gelida Wheeler (Formicidae)
SO Southwestern Naturalist, 29(4):423-427
DE Ecology
; Genetics
; University of Colorado
; Niwot Ridge
; Temperature
; Thermoregulation
; Insects
AB None
$
CL 0077a
AU Bernstein, R.A.
DT 1984
TI Comparative worker size and reproductive output of subpopulations of the
 alpine ant, Formica gelida Wheeler (Formicidae)
SO Southwestern Naturalist, 29(4):423-427
DE Journal
; Ecology
; University of Colorado
; Niwot Ridge
; Insects
; Climate - Discussion of
; Morphological
; Demography
; Reproduction
; Growth (Development)
AB None
$
CL 0077
AU Bernstein, R.A.
DT 1976
TI The adaptive value of polymorphism in an alpine ant, Formica neorufibarbis
 gelida Wheeler
SO Psyche, 83(2):180-184
DE Ecology
; Genetics
; University of Colorado
; Niwot Ridge
; Temperature
; Insects
; Bioenergetics
; Reproduction
AB None
$
CL 1338
AU Bieber A.J.
; Williams M.W.
; Johnsson M.J.
; Davinroy T.C.
DT 1998
TI Nitrogen transformations in alpine talus fields, Green Lakes Valley, Front Range,
 Colorado, U.S.A
SO Arctic and Alpine Research 30:266-271
DE NWTLTER
; alpine 
; talus fields
; nitrogen 
; nitrification
; nitrogen mineralization
AB This study reports the first direct evidence of nitrogen (N) transformations
 in alpine talus fields. Mineralization (conversion of organic N to inorganic
 N) and nitrification (conversion of ammonium [NH4+] to nitrate [NO3-]) rates
 were measured in pockets of fine material in talus slopes of an alpine catchment 
 of the Colorado Front Range, U.S.A., in 1996. Rates of both processes were higher
 in patches with vegetation covering >80% of the surface area than in patches
 with vegetation covering <20% of the surface area. In the mid- to late growing
 season, net mineralization rates at vegetated sites of 2.49 mg N/kg/d were
 significantly greater than the 0.39 mg N/kg/d at unvegetated sites (p=0.03).
 Net nitrification rates of 1.0 mg N/kg/d at sites with vegetation were significantly
 greater than the 0.27 mg N/kg/d at unvegetation sites (p=0.01). These rates
 of N transformation were comparable to mineralization and nitrification rates
 reported for well-developed tundra soils nearby on Niwot Ridge. Mineralization
 and nitrification rates varied inversely with elevation along a transect with
 a 100 m elevational change (p=0.005, p=0.025). Nitrogen mineralization and
 nitrification in talus may help explain elevated levels of NO3- in alpine 
 streams in mid- to late summer.
$
CL 1414
AU Bilbrough, C.J.
; Welker, J.M.
; Bowman, W.D.
DT 2000
TI Early spring nitrogen uptake by snow-covered plants: a comparison of arctic and alpine plant function under the snowpack 
SO Arctic, Antarctic, and Alpine research 31: 191-195 
DE None
AB We compared nitrogen (N) acquisition by alpine and arctic tundra plants during snowmelt, and assessed its significance relative to season-long N demand. We then related plant responses in alpine and arctic tundra to soil and air temperature. Parallel experiments were conducted in an alpine moistmeadow at Niwot Ridge, Colorado, and in arctic dry heath and moist tussock tundra near Toolik Lake, Alaska. We added 99%-enriched 15NH4, 15NO3 (0.5 g N m-2) to the snowpack, and traced the fate of 15N into plants and soil by harvesting samples before snowmelt ended. All alpine and arctic plants aquired N during snowmelt. However, alpine plants acquired 100 times more N than arctic plants. Using data from published studies, we estimated season-long N demand for the vascular plant species. In the alpine tundra, N uptake during snowmelt constituted over 12% of season-long uptake for a graminoid species, and averaged 7.4% for perennial forbs. In contrast, N uptake during snowmelt by arctic plants averaged less than 0.1% of season long N uptake. Soil temperatures were similar in these systems during snowmelt, averaging -0.4 degrees C in the arctic tundra and -0.5 degrees C in the alpine tundra. However, arctic plants experienced lower winter soil temperatures than alpine plants. Winter soil surface temperatures averaged -7.75 degrees C in arctic and -2.43 degrees C in alpine tundra systems, and the lowest weekly mean temperature was -14.5 degrees C in the arctic and -6.14 degrees C in the alpine systems. Thus, differences in plant N uptake are likely due to winter conditions, rather than conditions that occurred during uptake. In conclusion, plant acquisition of N resources during snowmelt is important in alpine systems.     $
CL 0079
AU Billings, W.D.
; Godfrey, P.J.
; Chabot, B.F.
; Bourque, D.P.
DT 1971
TI Metabolic acclimation to temperature in arctic and alpine ecotypes of Oxyria
 digyna
SO Arctic and Alpine Research, 3:277-289
DE Ecology
; Niwot Ridge
; Physiological
; Metabolism
; Temperature
; Angiosperms
AB None
$
CL1462
AU Bingham, R.A.
; Ort, A.R.
DT 1998
TI Efficient pollination of alpine plants
SO Nature 391:238-239
DE NWTLTER
AB None
$
CL 0081
AU Bliss, L.C. (ed.)
; Wielgolaski, F.E. (ed.
2000
)
DT 1973
TI Proceedings of the Conference on Primary Production and Production
 Processes, Tundra Biome Dublin, Ireland, April 1973.
SO Stockholm: IBP Tundra Biome Steering Committee 256 pp.
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Physiological
; Photosynthesis
; Productivity
; Plant
AB None
$
CL 0083
AU Bollinger, M.J.
DT 1982
TI Chemiluminescent measurements of the oxides of nitrogen in the clean
 troposphere and atomospheric chemistry implications
SO Ph.D. dissertation, University of Colorado, Boulder. 251 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Community
; Distribution
; Fire
; Angiosperms
AB None
$
CL 0084a
AU Bollinger, M.J.
; Hahn, C.J.
; Parrish, D.D.
; Murphy, P.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
DT 1984
TI NOx measurements in clean continental air and analysis of the contributing
 meteorology
SO Journal of Geophysical Research, 89:9623-9631
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; nitrogen compounds
; climatology
AB None
$
CL 0084
AU Bollinger, W.H.
DT 1973
TI The vegetation patterns after fire at the alpine forest-tundra ecotone in
 the Colorado Front Range
SO Ph.D. dissertation, University of Colorado. 75 pp.
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Wind
; Nitrogen
AB None
$
CL 0093
AU Bonde, E.K.
; Foreman, M.F.
DT 1973
TI Growth and development of arctic and alpine grasses in experimental gardens
 at various altitudes in Colorado, U.S.A.
SO In: Bliss, L.C. and Wielgolaski, F.E. (eds.), Proceedings of the Conference
 on Primary Production and Production Processes, Tundra Biome. Dublin, Ireland,
 April 1973. Stockholm: IBP Tundra Biome Steering Committee,87-97
DE Ecology
; U.S. International Biological Programme
; A-1 Climate Station
; Growth (Development)
; Angiosperms
AB None
$
CL 0094
AU Bonde, E.K.
; Foreman, M.F.
DT 1973
TI Plant growth rates, phenology, and productivity in experimental gardens,
 Front Range, Colorado
SO U.S. Tundra Biome Data Report, 73-11. 28 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; A-1 Climate Station
; Phenological (seasonal)
; Growth (Development)
; Productivity
; Angiosperms
AB None
$
CL 0095
AU Bonde, E.K.
; Foreman, M.F.
; Babb, T.A.
; Kjelvik, S.
; McKendrick, J.D.
; Mitchell, W.W.
; Wooding, F.J.
; Tieszen, L.L.
; Younkin, W.
DT 1973
TI Growth and development of three agronomic species in pots ("phytometers")
SO In: Bliss, L.C. and Wielgolaski, F.E. (eds.), Proceedings of the Conference
 on Primary Production and Production Processes, Tundra Biome. Dublin, Ireland,
 April 1973. Stockholm: IBP Tundra Biome Steering Committee, 99-110
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Growth (Development)
; Angiosperms
AB None
$
CL 0085
AU Bonde, E.K.
DT 1948
TI Damage by spring frosts to young shoots of Picea engelmannii and Abies
 lasiocarpa in Colorado
SO M.A. thesis, University of Colorado, Boulder. 63 pp.
DE Thesis
; Ecology
; University of Colorado
; Niwot Ridge
; Frost
; Physiological
; Growth (Development)
; Conifers
AB None
$
CL 0092
AU Bonde, E.K.
; Flock, J.W.
; Shushan, S.
; Funk, D.W.
DT 1982
TI Fungal diseases in Colorado alpine plants
SO Journal Colorado-Wyoming Academy of Sciences, 14(1):47. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Disease
; Fungi
; Angiosperms
AB None
$
CL 0091
AU Bonde, E.K.
; Flock, J.W.
; Shushan, S.
DT 1982
TI Air pollution and the ecology of plants
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37:101-112
DE Ecology
; Overview
; Long Term Ecological Research Program
; Acid Deposition
; Pollution
; Lichens
; Tracheophytes
; Bryophytes
; NWTLTER
AB None
$
CL 0096
AU Bondurant, L.D.
DT 1933
TI A study of secondary vegetation on an artificially denuded area in the
 montane zone of Colorado
SO M.A. thesis, University of Colorado, Boulder. 112 pp.
DE Thesis
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Community
; Succession
; Angiosperms
AB None
$
CL 0099
AU Bonnett, R.B.
DT 1970
TI The glacial sequence of upper Boulder Creek drainage basin in the Colorado
 Front Range
SO Ph.D. dissertation, Ohio State University. 318 pp.
DE Dissertation
; Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0100
AU Bonnett, R.B.
DT 1970
TI Wisconsin glaciation of the upper Boulder Creek drainage basin, Colorado
 Front Range
SO American Quaternary Association. Abstracts of First Meeting, 13. Abstract
DE Abstract
; Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0104
AU Bovis, M.J.
DT 1982
TI The spatial variation of soil loss and soil loss controls
SO In: Thorn, C.E. (ed.), Space and Time in Geomorphology. The'Binghamton'
 Symposia in Geomorphology: International Series, No. 12. London: George Allen
 and Unwin, 1-24
DE Geomorphology
; Sedimentology
; Hydrology
; Soil sciences
; Niwot Ridge
; Soil
; Water
AB None
$
CL 0105
AU Bovis, M.J.
; Thorn, C.E.
DT 1981
TI Soil loss variation within a Colorado alpine area
SO Earth Surface Processes and Landforms, 6:151-163
DE Geomorphology
; Sedimentology
; Hydrology
; Soil sciences
; Niwot Ridge
; Soil
; Water
AB None
$
CL 0102
AU Bovis, M.J.
DT 1974
TI Rates of soil movement in the Front Range, Boulder County, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 254 pp.
DE Dissertation
; Geomorphology
; Soil sciences
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Soil
; Water
AB None
$
CL 0103
AU Bovis, M.J.
DT 1978
TI Soil loss in the Colorado Front Range: Samping design and areal variation
SO Zeitschrift fur Geomorphologie, 29:10-21. Reprinted in: Ives,J.D. (ed.),
 1980: Geoecology of the Colorado Front Range. Boulder: Westview Press, 187-198
DE Technique
; Geomorphology
; Hydrology
; Soil sciences
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Soil
; Water
AB None
$
CL 1411
AU Bowman, W.D
; T.R. Seastedt
DT 2001
TI Structure and function of an alpine ecosystem: Niwot Ridge, Colorado
SO Oxford University Press 
DE None
AB None
$
CL 1517
AU Bowman, W.D.
DT 2003
TI The response of alpine plants to environmental change - Feedbacks to ecosystem function.  
SO in: Huber, U., Buggmann, H. and Reasoner, M. Global Change and Mountain Regions: A State of Knowledge Overview.  Kluwer Academic Press.
DE NWTLTER
AB None
$
CL 1356
AU Bowman, W.D.
; Keller, A.
; Nelson, M.
DT 1999
TI Altitudinal variation in leaf gas exchange, nitrogen and phosphorus concentrations
 and leaf mass per area in populations of Frasera speciosa
SO Arctic, Antarctic, and Alpine Research 31:191-195
DE NWTLTER
; nitrogen
; phosphorus
; Frasera speciosa
AB Foliar nitrogen (N) and phosphorus (P) concentrations, leaf mass per unit area (LMA), 
 and leaf gas exchange were measured in seven populations of Frasera speciosa along a 1700 m 
 gradient, to assess whether altitudinal variation n net photosynthesis rates was related to 
 foliar N and P concenetrations, LMA, and stomatal conductance.  A secondary goal was to 
 evaluate whether altitudinal trends in foliar chemistry were independent of phenology of 
 the plants. Leaf N and P concentrations per unit mass changed seasonally in all populations, 
 but increased with altitude throughout the growing season.  Leaf mass per unit area decreased 
 with increasing altitude, unlike most other studies which have found LMA to increase with altitude.  
 As a result foliar N per unit area of leaf did not change with increasing altitude.  Net 
 photosynthesis rates and stomatal conductance did not change with increasing altitude.  
 Transpiration rates increased, while water-use efficiency and the 
2000
mole fraction of intercellular 
 CO2 decreased with increasing altitude.  The change in LMA was the predominant response to 
 increasing altitude in populations of Frasera, and assuming the decrease in CO2 partial pressure 
 with increasing altitude imposes a constraint on photosynthesis, increased internal conductance 
 and/or increased photosynthetic capacity may have resulted in maintenance of similar field 
 photosyntheis rates among populations.        
$
CL 1219
AU Bowman, W.D.
DT 1992
TI Inputs and storage of nitrogen in winter snowpack in an alpine ecosystem
SO Arctic and Alpine Research 24: 211-215
DE NWTLTER
; Niwot Ridge
; inorganic nitrogen
; nitrate
; ammonium
; snow chemistry
; meltwater chemistry
AB Inorganic nitrogen concentrations in winter snow were measured on Niwot
 Ridge, Colorado, to estimate the potential inputs of this nutrient into an
 alpine ecosystem for support of early season growth of plants and soil
 microorganisms. Concentrations of both NO3-N and NH4-N increased in snow from
 February to May, reaching maximum values just prior to the onset of the
 growing season, which commences in early to mid-June. Vertical profiles of
 nitrogen concentration indicated downward movement of N in meltwater beginning
 in April. The highest N concentrations from April to May were found just above
 ice lenses. Potential N inputs into four plant communities from N released in
 snowmelt in 1990 and 1991 varied primarily according to differences in snow
 depth, and ranged from 53 mg/m^2/yr in a dry meadow community to 606 mg/m^2/yr
 in a snowbed community. This represents approximately 14 to 101% of the
 potential total atmospheric inputs of N from estimations of bulk deposition
 without horizontal redistribution of snow, and is as much as 30% of inputs
 from net N mineralization of soil organic matter. Thus reservoirs of N in
 snowpack are a potentially large source of N supporting plant growth, and may
 explain in part the spatial heterogeneity of primary production in alpine
 ecosystems.
$
CL 1572
AU Bowman, W.D.
DT 2005
TI The response of alpine plants to environmental change: Feedbacks to ecosystem function 
SO in U. M. Huber, H. K. M. Bugmann, and M. A. Reasoner (eds.) Global Change and Mountain Regions (A State of Knowledge Overview).  Springer, Dordrecht.
DE NWTLTER
; Book Chapter
; Book
AB None
$
CL 1347
AU Bowman, W.D.
; Steltzer, H.
DT 1998
TI Positive feedbacks to anthropogenic nitrogen deposition in Rocky Mountain alpine tundra
SO Ambio 27:514-517
DE NWTLTER
; plant species composition
; nitrogen deposition
; net nitrogen mineralization
; net nitrification
; alpine tundra
AB Increasing deposition of anthropogenic N may detrimentally impact
 terrestrial and aquatic ecosystems. Research on the impacts of N
 deposition has focused primarily on regions with rates > 10 kg N
 per hectare per year, yet lower rates may substantially impact 
 ecosystems with lower biological capacity to sequester the 
 additional inputs of N. Alpine tundra, due to low rates of primary
 production and soil microbial activity, is susceptible to biotic
 impacts resulting from high N deposition. Increases in N availability
 in alpine tundra of the southern Rocky Mountains, which is experiencing
 elevated rates of N deposition from anthropogenic sources (8-10 kg
 N per hectare per year), will lead to changes in plant species
 composition as a result of competitive displacement. Such changes in
 plant community structure will have positive feedbacks to rates of 
 N cycling. In moist meadow communities, replacement of the dominant
 Acomastylis rossii by Deschampsia caespitosa will lead to an eightfold
 increase in net N mineralization and nitrification rates, which
 in turn will increase groundwater loss of NO3- to aquatic ecosystems.
$
CL1475
AU Bowman, W.D.
; Cairns, D. M.
; Baron, J.S.
; Seastedt, T.R.
DT 2002
TI Islands in the sky: Tundra and treeline
SO In: Baron, J.S., D. Fagre, and R. Hauer (eds.) Rocky Mountain Futures: an Ecological Perspective. Island Press
DE None
AB None
$
CL 1412
AU Bowman, W.D.
; Fisk, M.C.
DT 2001
TI Primary Production
SO In: Bowman, W.D. and T.R. Seastedt (eds). Structure and function of an alpine
 ecosytem: Niwot Ridge, Colorado. Oxford University Press
DE None
AB None
$ 
CL 1415
AU Bowman, W.D.
DT 2000
TI Biotic controls over ecosystem response to environmental change in alpine tundra of the Rocky Mountains  
SO Ambio 29: 396-400
DE None
AB None
$
CL 1308
AU Bowman, W.D.
; Schardt, J.C.
; Schmidt, S.K.
DT 1996
TI Symbiotic N2-fixation in alpine tundra: ecosysem input and variation
 in fixation rates among communities
SO Oecologia 108: 345-350
DE NWTLTER
; alpine ecosystem
; delta 15N
; nitrogen cycling
; symbiotic N2-fixation
; trifolium
AB Annual inputs of symbiotic N2-fixation associated with 3 species of
 alpine Trifolium were estimated in four alpine communities differing in
 resource supplies. We hypothesized that fixation rates would vary according
 to the degree of N, P, and water limitation of production, with the higher
 rates of fixation in N limited communities (dry meadow, moist meadow) and
 lower rates in P and water limited communities (wet meadow, fellfield).
 To estimate N2-fixation rates, natural abundance of N isotopes (delta 15N)
 were measured in field collected Trifolium and reference plants and in 
 Trifolium plants grown in N-free medium in a growth chamber. All three
 Trifolium species relied on a large proportion of atmospherically-fixed
 N2 to meet their N requirements, ranging from 10 to 100%. There were no
 apparent differences in the proportion of plant N derived from fixation 
 among the communities, but differences in the contribution of the Trifolium
 species to community cover resulted in a wide range of annual N inputs
 from fixation, from 127 mg per square meter per year in wet meadows to 
 810 mg per square meter per year in fellfields. Annual spatially integrated
 inputs of symbiotic N2-fixation to Niwot Ridge, Colorado was estimated
 at 490 mg per square meter per year (5 kg per hectare per year), which is
 relatively high in the context of estimates of net N mineralization and
 N deposition.
$ 
CL 1444
AU Bowman, W.D.
; Bilbrough, C.J.
DT 2001
TI Influence of a pulsed nitrogen supply on growth and nitrogen uptake in alpine graminoids
SO Plant and Soil 233: 283-290
DE None
AB None
$
CL1476
AU Bowman, W.D.
; Damm, M.
DT 2002
TI Causes and consequences of vascular plant diversity in the Rocky Mountain alpine
SO In: Mountain biodiversity: a global assessment,(Ch. Krner and E. Spehn, eds)  Parthenon Publishing, London, UK
DE None
AB None
$
CL1553
AU Bowman, W.D.
; Steltzer, H.
; Rosenstiel, T.N.
; Cleveland, C.C.
; Meier, C.L.
DT 2004
TI Litter effects of two co-occurring alpine species on plant growth, microbial activity and immobilization of nitrogen
SO OIKOS vol. 104 pp. 336-344
DE NWTLTER
AB We measured the litter chemistry of two co-dominant alpine species, Acomastylis rossii, a forb characterized by a low growth rate and N uptake capacity, and Deschampsia caespitosa, a grass characterized by a high growth rate and N uptake capacity, and examined the effect litter of these two species had on the growth of Deschampsia phytometers in a greenhouse. We also examined the influence of litter from the two species on microbial respiration and immobilization of N, in two separate laboratory microcosm experiments and in the field. We hypothesized that Acomastylis litter would reduce plant growth more than Deschampsia litter, corresponding with either 1) suppression of microbial activity and thus a decrease in N mineralization, or 2) by stimulation of microbial biomass and increasing microbial immobilization of N. Relative to Deschampsia litter, Acomastylis litter had higher total water soluble organic carbon (DOC), and higher total phenolic concentration. Deschampsia litter had 30 times higher carbohydrate (primarily glucose and fructose) concentrations than Acomastylis litter. Soil respiration, microbial biomass N, 
2000
and consumption of DOC and N were higher with the Acomastylis litter treatment than the Deschampsia litter treatment in experimental microcosms, and both respiration and microbial biomass N were higher in field soils under canopies dominated by Acomastylis relative to those dominated by Deschampsia. These results indicate that phenolics in Acomastylis are a C source for soil microorganisms, rather than an inhibitor of microbial activity. Deschampsia phytometers grew significantly less, had higher root: shoot biomass ratios, and acquired less nitrogen in the Acomastylis litter treatment relative to the control and Deschampsia litter treatments. The results of these experiments indicate that Acomastylis litter influences soil N cycling by increasing microbial activity and N immobilization, which may influence N supply to neighboring plants. This mechanism has the potential to influence competitive interactions between Acomastylis and its neighbors.
$
CL 1267
AU Bowman, W.D.
; Theodose, T.A.
; Fisk, M.C.
DT 1995
TI Physiological and production responses of plant growth forms to 
 increases in limiting resources in alpine tundra: Implications for
 differential community response to environmental change
SO Oecologia 101:217-227
DE NWTLTER
; Niwot Ridge
; alpine tundra
; nitrogen
; physiological response to resource additions
; plant growth form
; primary production
AB Physiological and growth measurements were made on forbs and graminoids
 following additions of water and N+water in a graminoid-dominated dry
 meadow and a forb-dominated moist meadow, to determine if the community-
 level response was related to differential responses between growth forms.
 Graminoids had higher photosynthetic rates and lower transpiration rates
 and foliar N concentrations than forbs, and consequently maintained
 higher photosynthetic N- and water-use efficiencies. Photosynthetic rates,
 stomatal conductance, and transpiration rates increased significantly only
 in response to N fertilization and only in moist meadow species. The 
 increase in photosynthetic rates was unrelated to variation in foliar N
 concentration, but instead correlated with variation in stomatal 
 conductance. Growth based N-use efficiency was higher in moist meadow 
 graminoids than in moist meadow forbs, but did not differ between the 
 growth forms in the dry meadow. The moist meadow community had higher 
 biomass and N standing crops, but the relative increase in these factors
 in response to N fertilization was greater in the dry meadow. Graminoids
 had a greater relative increase in biomass and N accumulation than forbs
 following N fertilization, but moist meadow graminoids exhibited a 
 greater response than dry meadow graminoids. The difference in the growth
 response between the dry meadow and moist meadow graminoids to N 
 fertilization was correlated with more conservative leaf gas exchange
 responses in dry meadow species, presumably related to a higher frequency
 of soil water deficits in this community. Community-level response to the
 resource additions was therefore mediated by the plant growth form 
 response, corresponding with differences between the growth forms in
 physiological factors related to resource acquisition and use.
$
CL 1248
AU Bowman, W.D.
DT 1994
TI Accumulation and use of nitrogen and phosphorus following fertilization in
 two alpine tundra communities
SO Oikos 70:261-270
DE NWTLTER
; Niwot Ridge
; fertilization
; nutrient use efficiency
; nutrient allocation
; nitrogen
; phosphorus
; nutrient cycling
AB To determine whether there are differences in the relative capacity of
 communities to accumulate nutrients and translate nutrient uptake into growth,
 N and P standing crops and use efficiencies were measured following
 fertilization in two alpine tundra communities. In general, differences in
 nutrient dynamics between the communities corresponded with the type and
 degree of nutrient limitation of production. The N-limited dry meadow had
 greater increases in aboveground N standing crop and tissue N concentration in
 response to N fertilization, higher N-use efficiency, and higher N resorption
 than the wet meadow. Conversely, the N-P co-limited wet meadow had a greater P
 accumulation response to P fertilization and higher P-use efficiency than the
 dry meadow. Differences in the response to the treatments and in nutrient use
 efficiencies were mediated largely by individual plant growth forms. Although
 there was a substantial amount of luxury consumption of N and P, there was
 evidence of co-regulated uptake relative to the availability of these
 nutrients in the soil.
$
CL 1493
AU Bowman, W.D.
; Bahn, L.
; Damm, M.
DT 2003
TI Alpine landscape variation in foliar nitrogen and phosphorus concentrations and the relation to soil nitrogen and phosphorus availability
SO Arctic, Antarctic and Alpine Research v. 35 pp. 144-149
DE NWTLTER
AB None
$
CL 1249
AU Bowman, W.D.
; Conant, R.T.
DT 1994
TI Shoot growth dynamics and photosynthetic response to increased nitrogen
 availability in the alpine willow Salix glauca
SO Oecologia 97:93-99
DE NWTLTER
; Niwot Ridge
; alpine ecosystem
; nitrogen-use efficiency
; photosynthesis
; Salix glauca
AB Plants subjected to increases in the supply of resource(s) limiting growth
 may allocate more of those resources to existing leaves, increasing
 photosynthetic capacity, and/or to production of more leaves, increasing
 whole-plant photosynthesis. The responses of three populations of the alpine
 willow, Salix glauca, growing along an alpine topographic sequence
 representing a gradient in soil moisture and organic matter, and thus
 potential N supply, to N amendments, were measured over two growing seasons,
 to elucidate patterns of leaf versus shoot photosynthetic responses. Leaf-
 (foliar N, photosynthesis rates, photosynthetic N-use efficiency) and shoot-
 (leaf area per shoot, number of leaves per shoot, stem weight, N resorption
 efficiency) level mesurements were made to examine the spatial and temporal
 variation in these potential responses to increased N availability. The
 predominant response of the willows to N fertilization was at the shoot-level,
 by production of greater leaf area per shoot. Greater leaf area occurred due
 to production of larger leaves in both years of the experiment and to
 production of more leaves during the second year of fertilization treatment.
 Significant leaf-level photosynthetic response occurred only during the first
 year of treatment, and only in the dry meadow population. Variation in
 photosynthesis rates was related more to variation in stomatal conductance
 than to foliar N concentration. Stomatal conductance in turn was significantly
 related to N fertilization. Differences among the populations in
 photosynthesis, foliar N, leaf production, and responses to N fertilization
 indicate N availability may be lowest in the dry meadow population, and
 highest in the ridge population. This result is contrary to the hypothesis
 that a gradient of plant available N corresponds with a snowpack/topographic
 gradient.
$
CL 1233
AU Bowman, W.D.
; Theodose, T.A.
; Schardt, J.C.
; Conant, R.T.
DT 1993
TI Constraints of nutrient availability on primary production in two alpine
 tundra communities
SO Ecology 74: 2085-2097
DE NWTLTER
; alpine tundra
; community response to nutrient amendments
; nitrogen
; nutrient limitation
; phosphorus
; photosynthesis
; primary production
AB A nutrient amendment experiment was conducted for two growing seasons in two
 alpine tundra communities to test the hypotheses that: (1) primary production
 is limited by nutrient availability, and (2) physiological and developmental
 constraints act to limit the responses of plants from a nutrient-poor
 community more than plants from a more nutrient-rich community to increases in
 nutrient availability. Experimental treatments consisted of N, P, and N+P
 amendments applied to plots in two physiognomically similar communities, dry
 and wet meadows. Extractable N a
2000
nd P from soils in nonfertilized control plots
 indicated that the wet meadow had higher N and P availability. Photosynthetic,
 nutrient uptake, and growth responses of the dominants in the two communities
 showed little difference in the relative capacity of these plants to respond
 to the nutrient additions. Aboveground production responses of the communities
 to the treatments indicated N availability was limiting to production in the
 dry meadow community while N production response to the N and N+P amendments
 in the dry meadow relative to the wet meadow, despite equivalent functional
 responses of the dominant species of both communities. The greater production
 response in the dry meadow was in part related to changes in community
 structure, with an increase in the proportion of graminoid and forb biomass,
 and a decrease in the proportion of community biomass made up by the dominant
 sedge Kobresia myosuroides. Species richness increased significantly in
 response to the N+P treatment in the dry meadow. Graminoid biomass increased
 significantly in the wet meadow N and N+P plots, while forb biomass decreased
 significantly, suggesting a competitive interaction for light. Thus, the
 difference in community response to nutrient amendments was not the result of
 functional changes at the leaf level of the dominant species, but rather was
 related to changes in community structure in the dry meadow, and to a shift
 from a nutrient to a light limitation of production in the wet meadow.
$ 
CL 1410
AU Bowman. W.D.
DT 2001
TI Introduction: Historical perspective and significance of alpine ecosystem studies
SO In: Bowman, W.D. and T.R. Seastedt (eds). Structure and function of an alpine ecosystem: Niwot Ridge, Colorado. Oxford University Press
DE None 
AB None
$
CL 0111
AU Braun, C.E.
; May, T.A.
DT 1972
TI Colorado alpine tundra avifaunal investigations, 1966-71
SO In: Bowen, S. (ed.), Proceedings 1972 Tundra Biome Symposium, Lake
 Wilderness Center, University of Washington, 3-5 April 1972, U.S. IBP Tundra
 Biome, 165-168
DE Climatology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Birds
AB None
$
CL 0113a
AU Brazel, A.J
; Arnfield, A.J.
; Greenland, D.E.
; Willmott, C.J.
DT 1991
TI Physical and boundary-layer climatology
SO Physical Geography 12(3):189-206
DE article
; climatology
; University of Colorado
; climate- discussion of
; NWTLTER
AB None
$
CL 0115
AU Brazel, A.J.
; Hyers, A.D.
DT 1979
TI Measurements of energy exchange at high altitude: Colorado Front Range
SO AAG Program Abstracts, Philadelphia
DE Abstract
; Climatology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Insolation
; Temperature
; Wind
AB None
$
CL 0114
AU Brazel, A.J.
; Brazel, S.W.
DT 1983
TI Summer diurnal wind patterns at 3000 m surface level, Front Range, Colorado
 U.S.A.
SO Physical Geography, 4:53-61
DE Climatology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Wind
AB None
$
CL 0116
AU Brazel, A.J.
; Hyers, D.
DT 1981
TI Comments on aspects of radiation transfer at high altitudes
SO Geography  Publication No. 1, Department of Geography, Arizona State
 University, Research Papers in Climatology, 1-19
DE Climatology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Insolation
; Temperature
; Wind
AB None
$
CL 0724c
AU Brendecke, C.M.
; Sweeten, J.G.
DT 1985
TI A simulation model of Boulder's alpine water supply
SO In:  Proceedings of the 53rd Annual Western Snow Conference pp. 63-71
DE Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Watershed
; NWTLTER
AB None
$
CL 0119
AU Brendecke, C.M.
; Laiho, D.R.
; Sweeten, J.
TI Management of a municipally owned alpine watershed using continuous
 simulations
DT 1984
SO 1984 International Symposium on Urban Hydrology, Hydraulic sand Sediment
 Control, University of Kentucky, Lexington, KY. July 23-26, 1984, 79-87
DE Model
; Hydrology
; Management
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Watershed
; Water
; Climate - Data Included
; NWTLTER
AB None
$
CL 0117
AU Brendecke, C.M.
; Laiho, D.
; Holden, D.
DT 1984
TI A comparative evaluation of streamflow simulation models in a Colorado
 alpine and subalpine environment
SO Proceedings of the American Geophysical Union, Front Range Branch Hydrology
 Days, April 24-26, 1984. Abstract
DE Abstract
; Model
; Hydrology
; Boulder Watershed and Rainbow Lakes
; Watershed
; Water
; Climate - Data Included
AB None
$
CL 0118
AU Brendecke, C.M.
; Laiho, D.
; Holden, D.
DT 1985
TI Comparison of two daily streamflow simulation models of an alpine watershed
SO Journal of Hydrology, 77:171-186
DE Model
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Watershed
; Water
; Climate - Data Included
; NWTLTER
AB None
$
CL 1342
AU Briggs, J.M.
; Benson, B.J.
; Hartman, M.A.
; Ingersoll, R.C.
DT 1998
TI Data entry
SO Data and information management in the ecological sciences: a resource guide. LTER
 Network Office, University of New Mexico, Albuquerque, NM
DE NWTLTER
; data entry
; data management
; information management
AB None
$
CL 0122
AU Brinkman, W.A.R.
DT 1974
TI Strong downslope winds at Boulder, Colorado
SO Monthly Weather Review, 102:592-602
DE Climatology
; University of Colorado
; C-1 Climate Station
; Altitude
; Wind
AB None
$
CL 0120
AU Brinkman, W.A.R.
DT 1973
TI A climatological study of strong downslope winds in the Boulder area
SO Ph.D. dissertation, University of Colorado, Boulder. 229 pp.
DE Dissertation
; Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Altitude
; Wind
AB None
$
CL 0121
AU Brinkman, W.A.R.
DT 1973
TI A climatological study of strong downslope winds in the Boulder area
SO University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper, 7. 228 p.
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Altitude
; Wind
AB None
$
CL 1511
AU Brooks, P. D. 
; Williams, M.W. 
DT 1999
TI Snowpack controls on nitrogen cycling and export in seasonally snow-covered catchments
SO in Snow Hydrology, the Integration of Physical, Chemical, and Biological Systems, ed. by J. P. Hardy, M. R. Albert, and P. Marsh, pp 2177-2190, Wiley Interscience.
DE NWTLTER
AB None
$
CL 1316
AU Brooks, P.D
; Schmidt, S.K.
; Williams, M.W.
DT 1997
TI Winter production of CO2 and N2O from alpine tundra: environmental
 controls and relationship to inter-system C and N fluxes
SO Oecologia 110: 403-413
DE NWTLTER
; trace gas flux
; carbon dioxide
; nitrous oxide
; snow cover
AB Fluxes of CO2 and N2O were measured from both natural and experimentally
 augmented snowpacks during the winters of 1993 and 1994 on Niwot Ridge in
 the Colorado Front Range. Consistent snow cover insulated the soil surface
 from extreme air temperatures and allowed heterotrophic activity to continue
 through much of the winter. In contrast, soil remained frozen at sites
 with inconsistent snow cover and production did not begin until snowmelt.
 Fluxes were measured when soil temperatures under the snow ranged from -5
 degrees C to 0 degrees C, but there was no significant relationship between
 flux for either gas and temperature within this range. While early developing
 snowpacks resulted in warmer minimum soil temperatures allowing production
 to continue for most of the winter, the highest CO2 fluxes were recorded
 at sites which experienced a hard freeze before a consistent snowpack
 developed. Consequently, the seasonal flux of CO2-C from snow covered soils
 was related both to the severity of freeze and the duration of snow cover.
 Over-winter CO2-C loss ranged from 0.3 g C per meter squared per season at
 sites characterized by inconsistent snow cover to 25.7 g C per meter squared
 per season at sites that experienced a hard freeze followed by an extended
 period of snow cover. In contras
2000
t to the pattern observed with C loss, a
 hard freeze early in the winter did not result in greater N2O-N loss. Both
 mean daily N2O fluxes and the total over-winter N2O-N loss were related to
 the length of time soils were covered by a consistent snowpack. Over-winter
 N2O-N loss ranged from less 0.23 mg N per meter squared from the latest
 developing, short duration snowpacks to 16.90 mg N per meter squared from
 sites with early snow cover. These data suggest that over-winter 
 heterotrophic activity in snow-covered soil has the potential to mineralize
 from less that 1% to greater than 25% of the carbon fixed in ANPP, while
 over-winter N2O fluxes range from less than half to an order of magnitude
 higher than growing season fluxes. The variability in these fluxes suggests
 that small changes in climate which affect the timing of seasonal snow
 cover may have a large effect on C and N cycling in these environments.
$
CL 1271
AU Brooks, P.D.
DT 1995
TI Microbial activity and nitrogen cycling under seasonal snowpacks, 
 Niwot Ridge, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 138 pp.
DE NWTLTER
; microbial activity
; nitrogen cycling
; snow
; Niwot Ridge
; nitrogen mineralization
; nutrient cycling
; trace gas flux
; denitrification
; microbial biomass
; biogeochemistry
AB Process level controls on microbial activity and nitrogen cycling
 during the snow covered season were identified in an alpine 
 ecosystem in the Colorado Front Range. Experiments were conducted
 to identify the controls on, and the spatial distribution of,
 microbial respiration under seasonal snowpacks, to quantify
 atmospheric N inputs, N mineralization, nitrification, 
 denitrification, N immobilization, and hydrologic export of N.
 Continuous snow cover was found to insulate soils from extreme air
 temperatures allowing soils to thaw well before the initiation of
 snowmelt. Soils thawed from the surface resulting in a clearly
 defined zone of microbial activity. Microbial respiration 
 increased as soils warmed and the active microbial population grew
 under the snowpack reaching maximum values of 500 to 600 mg CO2-C
 per m2 per day. Nitrogen mineralization was highest in soils which
 froze early in the year and then exhibited high levels of
 heterotrophic microbial activity under a continuous snowpack.
 Nitrification was significantly higher under shallow snowpacks
 characterized by lower levels of heterotrophic respiration.
 Microbial biomass increased throughout the spring in thawed soils
 reaching seasonal peaks shortly before snowmelt and decreased
 rapidly as sites became snow free. The increase in microbial
 biomass N was more than sufficient to immobilize inorganic N
 inputs from mineralization of soil organic matter. This activity
 is apparently responsible for the observation of no net export of
 N in surface water. Frozen soil below the active layer limited 
 export of N in subsurface flowpaths resulting in only gaseous 
 losses of N from the system. Denitrification N loss ranged from
 trace amounts to 250 ug N2O-N per m2 per day depending on the 
 depth and timing of snowpack accumulation. Together, these data
 suggest that microbial activity in snow covered soils is 
 important in controlling the export of N in surface water, as
 well as potentially providing an N source for vegetation early 
 in the growing season.
$
CL 1293
AU Brooks, P.D.
; Williams, M.W.
; Schmidt, S.K.
DT 1996
TI Microbial activity under alpine snowpacks, Niwot Ridge, Colorado
SO Biogeochemistry 32:93-113
DE NWTLTER
; Niwot Ridge
; alpine
; biogeochemistry
; nitrogen
; nitrogen saturation
; snowmelt
; soils
AB Experiments were conducted during 1993 at Niwot Ridge in the Colorado
 Front Range to determine if the insulating effect of winter snow cover
 allows soil microbial activity to significantly affect nitrogen inputs
 and outputs in alpine systems. Soil surface temperatures under seasonal
 snowpacks warmed from -14 degrees C in January to 0 degrees C by May 4th.
 Snowmelt began in mid-May and the sites were snow free by mid June. 
 Heterotrophic microbial activity in snow-covered soils, measured as CO2
 production was first identified on March 4, 1993. Net CO2 flux increased
 from 55mg CO2-C per meter per day in early March to greater than 824mg
 CO2-C per meter per day by the middle of May. Carbon dioxide production
 decreased in late May as soils became saturated during snowmelt. Soil 
 inorganic N concentrations increased before snowmelt, peaking between
 101 and 276mg per kg of soil in May, and then decreasing as soils became
 saturated with melt water. Net N mineralization for the period of March
 3 to May 4 ranged from 2.23 to 6.63g N per square meter, and were 
 approximately two orders of magnitude greater than snowmelt inputs of 
 50.4mg N per square meter for NH4+ and 97.2mg N per square meter for
 NO3-. Both NO3- and NH4+ concentrations remained at or below detection 
 limits in surface water during snowmelt, indicating the only export of 
 inorganic N from the system was through gaseous losses. Nitrous oxide
 production under snow was first observed in early April. Production 
 increased as soils warmed, peaking at 75 micrograms N2O-N per square
 meter per day in soils saturated with melt water one week before the
 sites were snow free. These data suggest that microbial activity in
 snow-covered soils may play a key role in alpine N cycling before 
 plants become active.
$
CL 1277
AU Brooks, P.D.
; Williams, M.W.
; Walker, D.A.
; Schmidt, S.K.
DT 1995
TI The Niwot Ridge snow fence experiment: Biogeochemical responses to
 changes in the seasonal snowpack
SO Pp. 293-302 In Tonnessen, K. A., M. W. Williams, and M. Tranter (eds.).
 Biogeochemistry of Seasonally Snow Covered Basins. International
 Association of Hydrological Sciences, Wallingford, UK, IAHS-AIHS
 Publication no. 228. 465 pp.
DE NWTLTER
; Saddle
; snow
; soil temperature
; microbial activity
; carbon dioxide
; carbon balance
; biogeochemistry
; Niwot Ridge
; nutrient cycles
AB We have implemented a long-term snow fence experiment at the Niwot 
 Ridge Long-Term Ecological Research site in the Colorado Front Range to 
 assess the effects of climate change on alpine ecology and biogeochemical 
 cycles. During the first winter after construction, the 2.6- x 60-m fence 
 resulted in a snowpack which was significantly deeper than adjacent areas. 
 The average period of continuous snow cover in the main snow fence drift
 (1994) was approximately 115 d longer than at control sites outside the 
 fence drift (1994), and 90 d longer than at the same sites the year before 
 construction of the fence (1993). The deeper and earlier snowpack behind 
 the fence insulated soils from extreme air temperatures resulting in a 9
 degrees Celsius increase in minimum soil surface temperatures, and a 12
 degreees C increase in minimum soil temperatures at a depth of 15 cm, 
 compared to prefence (1993) conditions. Warmer soils allowed microbial 
 activity, measured as carbon dioxide flux through the snowpack, to continue 
 through much of the winter. Carbon dioxide production under the deeper, 
 earlier snowpack after construction of the fence was 55% greater than 
 production before construction of the fence. The loss of CO2 from snow-
 covered soils was approximately 20% of aboveground primary production 
 before and 31% after construction of the fence. Areas with shallower
 snowpacks showed opposite trends with greatly reduced CO2 production. These 
 data suggest that small changes in the timing and depth of snowpack 
 accumulation may have a large effect on carbon balance and associated 
 biogeochemical cycles in alpine ecosystems.
$
CL 1276
AU Brooks, P.D.
; Williams, M.W.
; Schmidt, S.K.
DT 1995
TI Snowpack controls on soil nitrogen dynamics in the Colorado alpine
SO Pp. 283-292 In Tonnessen, K. A., M. W. Williams, and M. Tranter (eds.). 
 Biogeochemistry of Seasonally Snow Covered Basins. International 
 Association of Hydrological Sciences,
2000
 Wallingford, UK, IAHS-AIHS 
 Publication no. 228. 465 pp.
DE NWTLTER
; nitrogen
; biogeochemistry
; Niwot Ridge
; nutrient cycles
; nitrogen mineralization
; nitrification
AB Experiments were conducted before and during spring snowmelt in 1993 and 
 1994 at Niwot Ridge in the Colorado Front Range to assess the degree of 
 interaction between inorganic nitrogen (N) deposited in seasonal snowpacks 
 and soil N pools in alpine environments. Soils typically froze in early 
 winter with minimum soil temperatures inversely related to the depth of 
 early season snowpacks. Minimum soil temperatures under late-accumulating,
 shallow snowpacks reached -10 to -14 degrees Celsius, while soils under 
 deeper, earlier snowpacks reached minimum temperatures of -5 to -6 degrees
 C. Mineralization and nitrification inputs to the soil inorganic N pool
 were an order of magnitude higher than snowmelt inputs and were controlled 
 by the timing and depth of snowpack accumulation. Ion exchange resin bags 
 located at the soil surface indicated that the actual N inputs at any 
 location were highly variable. About 90% of isotopically labelled 15NH4+ 
 applied to the snow surface before melt was recovered in soil pools. 
 Nitrogen mineralization in 1994 was generally higher (1712 - 1960 mg N/m^2) 
 and exhibited relatively little spatial variability (CV 0.04 - 0.26) under 
 deeper, earlier accumulating snowpacks. In contrast, N mineralization under
 shallower, late-accumulating snowpacks was lower (511 - 1440 mg N/m^2) and 
 much more variable (CV 0.42 - 0.83). The lowest nitrification rates were 
 found under deep/early snowpacks (8 - 18% of mineralized N); the highest 
 were found under shallow/late snowpacks (16 - 58% mineralized N). These 
 results indicate the timing and depth of snowpack accumulation plays a key 
 role in nitrogen cycling in alpine ecosystems and may control inorganic
 nitrogen export in surface waters. 
$
CL 1269
AU Brooks, P.D.
; Schmidt, S.K.
; Sommerfeld, R.
; Musselman, R.
DT 1994
TI Distribution and abundance of microbial biomass in Rocky Mountain
 spring snowpacks
SO Pp. 301-306 In: Ferrik, M. (ed.). Proceedings of the Fiftieth Annual
 Eastern and Western Snow Conference, Quebec City, Quebec, Canada, 8-
 10 June 1993. 441 pp.
DE NWTLTER
; Niwot Ridge
; Rocky Mountains
; snowpack
; microbial biomass
; bacteria
; fungi
; nutrient cycling
; biogeochemistry
AB Snowpacks in both Colorado and Wyoming were sampled on 15 dates for
 total microbial biomass, ratio of bacteria to fungi, and major 
 inorganic ions. Levels of viable microbial biomass remained low
 throughout the period, peaking at 0.05 micrograms carbon/ml. 
 Microscopic analyses indicated this biomass was composed primarily of
 bacteria. Fungi were not detected in samples taken at or above 
 treeline. With the exception of one date in early May at the Colorado
 site, bacteria were confined to a band within the snowpack 
 approximately 20 cm above the snow/soil interface. Laboratory
 incubations using two Gram negative, motile rods isolated from this
 layer indicated these organisms were capable of growth from -0.5 to
 0.5 degrees Celsius but had optimum growth temperatures between 20 
 and 37 degrees Celsius. Based on observed population sizes and growth 
 rates it is unlikely these organisms were capable of significantly 
 affecting trace gas emissions or altering the chemical composition of 
 snowmelt.
$ 
CL 1416
AU Brooks, P.D.
; McKnight, D.M.
; Bencala, K.E.
DT 1999
TI The relationship between soil heterotrophic activity, soil dissolved organic carbon (DOC) leachate, and cachment-scale DOC export in headwater catchments
SO Water Resources Research. 35:1895-1902
DE None
AB None
$
CL 1343
AU Brooks, P.D.
; Williams, M.W.
; Schmidt, S.K.
DT 1998
TI Inorganic nitrogen and microbial biomass dynamics before and during spring snowmelt
SO Biogeochemistry 43:1-15
DE NWTLTER
; alpine
; nitrogen cycling
; nitrogen saturation
; snowmelt
; tundra
AB Recent work in seasonally snow covered ecosystems has identified thawed soil and high
 levels of heterotrophic activity throughout the winter under consistent snow cover. We
 performed measurements during the winter of 1994 to determine how the depth and timing
 of seasonal snow cover affect soil microbial populations, surface water NO3- loss during
 snowmelt, and plant N availability early in the growing season. Soil under early accumulating,
 consistent snow cover remained thawed during most of the winter and both microbial biomass
 and soil inorganic N pools gradually increased under the snowpack. At the initiation of
 snowmelt, microbial biomass N pools increased from 3.0 to 5.9 g N per meter squared,
 concurrent with a decrease in soil inorganic N pools. During the latter stages of snowmelt,
 microbial biomass N pools decreased sharply without a concurrent increase in inorganic N pools
 or significant leaching losses. In contrast, soil under inconsistent snow cover remained
 frozen during most of the winter. During snowmelt, microbial biomass initially increased from
 1.7 to 3.1 g M per meter squared and then decreased as sites became snow-free. In contrast to
 smaller pool sizes, NO3- export during snowmelt from the inconsistent snow cover sites of
 1.14 (+/-0.511) g N per meter squared was significantly greater (p<0.001) than the 0.27
 (+/-0.16) g N per meter squared exported from sites with consistent snow cover. These data
 suggest that microbial biomass in consistently snow-covered soil provides a significant
 buffer limiting the export of inorganic N to surface water during snowmelt. However, this
 buffer is very sensitive to changes in snowpack regime. Therefore, interannual variability
 in the timing and depth of snowpack accumulation may explain the year to year variability
 in inorganic N concentrations in surface water in these ecosystems.
$
CL 1365
AU Brooks, P.D.
; Williams, M.W.
DT 1999
TI Snowpack controls on nitrogen cycling and export in seasonally
 snow-covered catchments
SO Hydrological Processes 13:2177-2190
DE NWTLTER
; snow
; nitrogen
; biogeochemistry
; climate
; water chemistry
AB Here we provide an overview of current research activities on nitrogen
 (N) cycling in high-elevation catchments of the Colorado Front Range.
 We then use this information to develop a conceptual model of how snow
 cover controls subnivial (below snowpack) microbial processes and N leachate 
 from the snow-soil interface to surface waters. This model is based on research
 that identifies subnivial processes as a major control on the leaching loss
 of N from soil during snowmelt. These subnivial soil processes are controlled
 by the development of the seasonal snow pack that insulates soil from cold
 air temperatures and allows heterotrophic microbial activity in the soil to 
 immobilize N. In this model the duration of snow-cover is divided into four 
 snowpack regimes; zone 1 is characterized by shallow-short duration snowpacks, 
 zone 2 is characterized by high interannual variability in snow depth and 
 duration, zone 3 is characterized by early developing, continuous snow 
 cover, and zone 4 is characterized by deep, long-duration snow cover 
 verging on perennial snowpacks. In zone 1, soils remain frozen and there is 
 little microvial activity and N leachate is high. In zone 2, total microbial 
 activity is highly variable and the amount of N leachate is highly variable. 
 In zone 3, total microbial activity is high and there is little N leachate. In 
 zone 5, microbial activity is reduced because of carbon limitation and N leachate
 is high. This model suggests that a portion of the spatial and temporal
 variability observed in N export from these seasonally snow-covered systems
 is due to variability in winter snow cover across landscape types and 
 inter-annually within a landscape type.
$
CL 0127
AU Brown, J.
; Liston, N.
; Murphy, D.
; Wats, J.
DT 1983
TI U.S. Tundra Biome Publication List
SO [U.S.Army] CRREL Special Report 83-29.  29 pp.
DE Bibliography
; Ecolo
2000
gy
; U.S. International Biological Programme
; Niwot Ridge
AB None
$
CL 0123
AU Brown, J.
DT 1971
TI The structure and function of the tundra ecosystem
SO U.S International Biological Program, Tundra Biome Report, 71-6. 26 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Community
AB None
$
CL 0124
AU Brown, J. (ed.)
DT 1973
TI 1971 Project and data set abstracts
SO U.S. Tundra Biome Data Report, 73-17. 35 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
AB None
$
CL 0126
AU Brown, J. (ed.)
DT 1973
TI U.S. Tundra Biome 1973 field project reports
SO U.S.Tundra Biome Data Report, 73-31. 57 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
AB None
$
CL 0125
AU Brown, J. (ed.)
DT 1973
TI U.S. Tundra Biome 1972 summer project reports
SO U.S. Tundra Biome Data Report, 73-3. 83 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
AB None
$
CL 0128
AU Brown, R.C.
DT 1983
TI Anatomy of a mesoscale instrumentation system
SO Fifth Symposium on Meteorological Observations and Instrumentation, Toronto,
 Ontario, Canada, April 11-15, 1983. Boston, Massachusetts: American
 Meteorological Society
DE Technique
; Climatology
; NOAA - Profs
AB None
$
CL 0128b
AU Brown, R.N.
; Southwick, C.H.
; Golian, S.C.
DT 1989
TI Male-female spacing, territorial replacement, and the mating system of pikas
 (Ochotona princeps)
SO Journal of Mammalogy 70:622-627
DE article
; biology
; behavior
; Long-Term Ecological Research Program
; Saddle
; lagomorphs
; behavior
; reproduction
; population
; NWTLTER
AB None
$
CL 0128a
AU Brown, R.N.
DT 1986
TI Recruitment, survivorship, and the spacing system of pikas
SO M.A. thesis, University of Colorado, Boulder. 72 pp
DE Thesis
; Ecology
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Lagomorphs
; Behavior
; Population
; Demography
; NWTLTER
AB None
$
CL 1348
AU Bryant, D.M.
; Holland, E.A.
; Seastedt, T.R.
; Walker, M.D.
DT 1998
TI Analysis of litter decomposition in an alpine tundra
SO Canadian Journal of Botany 76:1295-1304
DE NWTLTER
; litter decomposition
; alpine tundra
; nitrogen deposition
; LIDET
; Niwot Ridge
AB Decomposition of plant litter regulates nutrient cycling and transfers of 
 fixed carbon to soil organic matter pools in terrestrial ecosystems. Climate, 
 as well as factors of intrinsic litter chemistry, often govern the rate of 
 decomposition and thus the dynamics of these processes. Initial concentrations 
 of nitrogen and recalcitrant carbon compounds are good predictors of litter 
 decomposition rates in many systems. The effect of exogenous nitrogen availability 
 on decay rates, however, is not well defined. Microclimate factors vary widely 
 within alpine tundra sites, potentially affecting litter decay rates at the local 
 scale. A controlled factorial experiment was performed to assess the influence 
 of landscape position and exogenous nitrogen additions on decomposition of surface 
 foliage and buried root litter in an alpine tundra in the Front Range of the 
 Rocky Mountains in Colorado, U.S.A. Litter bags were place in three communities 
 representing a gradient of soil moisture and temperature. Ammonium nitrate was 
 applied once every 30 days at a rate of 20 g N per square meter during the 3-month 
 growing season. Data, as part of the Long-Term Inter-site Decomposition Experiment 
 Team project, were analyzed to ascertain the effects of intrinsic nitrogen and 
 carbon fraction chemistry on litter decay in alpine systems. Soil moisture was 
 found to be the primary controlling factor in surface litter mass loss. Root 
 litter did not show significant mass loss following first growing season. Nitrogen 
 additions had no effect on nitrogen retention, or decomposition, of surface or 
 buried root litter compared with controls.  The acid-insoluble carbon fraction 
 was a good predictor of mass loss in surface litters, showing a strong negative 
 correlation. Curiously, N concentration appeared to retard root decomposition, 
 although degrees of freedom limit the confidence of this observation. Given the 
 slow rate of decay and N loss from root litter, root biomass appears to be a 
 long-term reservoir for C and N in the alpine tundra.
$
CL 1323
AU Bryant, D.M.
DT 1996
TI  Litter decomposition in an alpine tundra. 
SO M.S. thesis, University of Colorado, Boulder. 51 pp.
DE NWTLTER
; litter
; decomposition
AB None
$
CL 1202
AU Buchanan, L.
DT 1986
TI Generation of a snow depletion curve.
SO Proceedings of the 54th Annual Meeting Western Conference pp. 122-133
DE NWTLTER
; Boulder City Watershed
; snow hydrology
; ablation
; modeling
AB None
$
CL 0129a
AU Buchanan, L.R.
DT 1986
TI A snow depletion curve for modeling runoff in an alpine basin
SO M.S. thesis, University of Colorado, Boulder, 143 pp.
DE thesis
; model
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; snow
; water
; watershed
AB None
$
CL 1445
AU Bugmann, H.
DT 2001
TI A comparative analysis of forest dynamics in the Swiss Alps and the Colorado Front Range
SO Forest Ecology and Management 145: 43-55
DE None
AB None
$
CL 0130a
AU Burkhalter, A.
DT 1988
TI Baeume und Wind, Jahrringbilder und Baumformen in windgestressten
 nadelholzern der subalpinen stufe. Front Range Colorado
SO Diplomarbeit thesis, Universitaet Basel, Basel, Switzerland. 127 pp
DE thesis
; ecology
; Mountain Research Station
; Indian Peaks Region
; conifers
; wind
; tree
; growth
AB None
$
CL 1488
AU Burns, D.A.
DT 2003
TI Atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming- a review and new analysis of past study results
SO Atmospheric Environment v. 37 pp. 921-932
DE NWTLTER
; atmospheric deposition
; nitrogen
; Colorado
; Rock mountains
; nitrogen saturation
AB The Rocky Mountain region of Colorado and southern Wyoming receives as much as 7kg ha(-1) yr(-1) of atmospheric nitrogen (N) deposition. an amount that may have caused changes in aquatic and terrestrial life in otherwise pristine ecosystems. Results from published studies indicate a long-term increase in the rate of atmospheric N deposition during the 20th century, but data from the National Atmospheric Deposition Program and Clean Air Status and Trends Network show no region-wide increase during the past 2 decades. Nitrogen loads in atmospheric wet deposition have increased since the mid-1980s, however, at three high elevation ( > 3000 m) sites east of the Continental Divide in the Front Range. Much of this increase is the result of increased ammonium (NH4+) concentrations in wet deposition. This suggests an increase in contributions from agricultural areas or from vehicles east of the Rocky Mountains and is consistent with the results of previous studies that have suggested a significant eastern source for atmospheric N deposition to the Front Range. The four sites with the highest NH4+ concentrations in wet deposition were among the six easternmost NADP sites, which is also consistent with a source to the east of the Rockies. This analysis found an increase in N loads in wet deposition at Niwot Ridge of only 0.013 kg ha(-1) yr(-1), more than an order of magnitude less than previously reported for this site. This lower rate of increase results from application of the non-parametric Seasonal Kendall trend test to mean monthly data, which failed a test for normality, in contrast to linear regression, which was applied to mean annual data in a previous study. Current upward trends in population growth and energy use in Colorado and throughout the west suggest a need for continued monitoring of atmospheric deposition of N, and may reveal more widespread trends in N deposition in the future.$
CL 1497
AU Burns, D.A.
DT 2004
TI The effects of atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming, USA- a critical review
SO Environmental Pollution v
2000
. 127(2004) pp. 257-269
DE Atmospheric nitrogen deposition
; Colorado
; Rocky Mountains
; Nitrogen saturation
; Lake chemistry
AB The Rocky Mountains of Colorado and southern Wyoming receive atmospheric nitrogen (N) deposition that ranges from 2 to 7 kg ha-1 yr-1, and some previous research indicates pronounced ecosystem effects at the highest rates of deposition.  This paper provides a critical review of previously published studies on the effects of atmospheric N deposition in the region.  Plant community changes have been demonstrated through N fertilization studies, however, N limitation is still widely reported in alpine tundra and subalpine forests of the Front Range, and sensitivity to changes in snow cover alone indicate the importance of climate sensitivity in these ecosystems.  Retention of N in atmospheric wet deposition is < 50% in some watersheds east of the Continental Divide, which reflects low biomass and a short growing season relative to the timing and N load in deposition.  Regional upward temporal trends in surface water NO-3 concentrations have not been demonstrated, and future trend analyses must consider the role of climate as well as N deposition.  Relative high rates of atmospheric N deposition east of the Divide may have altered nutrient limitation of phytoplankton, species composition of diatoms, and amphibian populations, but most of these effects have been inconclusive to date, and additional studies are needed to confirm hypothesized cause and effect relations.  Projected future population growth and energy use in Colorado and the west increase the likelihood that the subtle effects of atmospheric N deposition now evident in the Front Range will become more pronounced and widespread in the future.$
CL 1563
AU Burns, D.A.
DT 2002
TI The Effects of Atmospheric Nitrogen Deposition in the Rocky Mountains of Colorado and Southern Wyoming-a Synthesis and Critical Assessment of Published Results
SO Water-Resources Investigations Report 02-4066.  U.S. Geological Survey. Troy, New York
DE NWTLTER
AB None.
$
CL 0135
AU Burns, S.F.
DT 1980
TI Mapping alpine soils using color positive and color infrared photographs
SO Presented at the 6th Purdue Symposium on Machine Processing of Remotely
 Sensed Data (in conjunction with the International Symposium on Soil
 Information and Remote Sensing), Purdue University, June 2-6, 1980
DE Geomorphology
; Remote sensing
; Soil sciences
; NASA - PY
; Indian Peaks Region
; Soil
AB None
$
CL 0141
AU Burns, S.F.
; Tonkin, P.J.
DT 1982
TI Soil-geomorphic models and the spatial distribution and development of
 alpine soils
SO In: Thorn, C.E. (ed.), Space and Time in Geomorphology, The 'Binghamton'
 Symposia in Geomorphology: International Series, No. 12. London: George Allen
 and Unwin, 25-43
DE Model
; Geomorphology
; Soil sciences
; Soil
AB None
$
CL 0132
AU Burns, S.F.
DT 1980
TI Alpine soil distribution and development, Indian Peaks, Colorado Front Range
SO Ph.D. dissertation, University of Colorado, Boulder. 360 pp.
DE Dissertation
; Geomorphology
; NASA - PY
; Indian Peaks Region
; Soil
; Soil sciences
; Distribution
AB None
$
CL 0134
AU Burns, S.F.
DT 1980
TI A comparison of mountain life zones of the Swiss Alps with the Colorado
 Front Range
SO Journal Colorado-Wyoming Academy of Science, 12(1): 31.Abstract
DE Abstract
; Ecology
; Mountain Research Station - Affiliation
; Altitude
; Climate - Discussion of
; Animals
; Plant
AB None
$
CL 0131
AU Burns, S.F.
DT 1979
TI The northern pocket gopher (Thomomys talpoides): A major geomorphic agent
SO Journal Colorado-Wyoming Academy of Sciences, 11(1):86
DE Abstract
; Ecology
; Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Soil
; Habitat
; Rodents
AB None
$
CL 0133
AU Burns, S.F.
DT 1980
TI Alpine soil factors in disturbance and revegetation
SO Presented at the Fourth High Altitude Revegetation - Recovery Workshop,
 Golden, Co, February 27, 1980
DE Geomorphology
; NASA - PY
; Management
; Soil sciences
; Soil
; Disturbances
; Revegetation
; Plant
AB None
$
CL 0139
AU Burns, S.F.
; Thorn, C.
DT 1984
TI Niwot Ridge soils, weathering and periglacial features
SO Guidebook for Field Trip 4, Eighth Biennial Meeting, American Quaternary
 Association, Boulder, Colorado, August 1984. 28 pp.
DE Guide
; Geomorphology
; Glaciology
; Soil sciences
; Niwot Ridge
; Soil
; Periglacial
AB None
$
CL 0142
AU Bursa, A.S.
DT 1970
TI Dinamoebidium coloradense spec. nov. and Katodinium auratum spec. nov. in
 Como Creek, Boulder County, Colorado
SO Arctic and Alpine Research, 2:145-151
DE Ecology
; Mountain Research Station - Location
; Stream
; Distribution
; Algae
AB None
$
CL 0144a
AU Bushnell, J.H.
; Foster, S.Q.
; Wahle, B.M.
DT 1987
TI Annotated inventory of invertebrate populations of an alpine lake and stream
 chain in Colorado
SO Great Basin Naturalist, 47(3):500-511
DE Ecology
; Taxonomy
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Insects
; Lake
; Stream
; Community
; Distribution
; Trophic
; NWTLTER
AB None
$
CL 0144
AU Bushnell, J.H.
; Butler, N.M.
; Pennak, R.W.
DT 1982
TI Invertebrate communities and dynamics of alpine flowages
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37:124-132
DE Ecology
; Long-Term Ecological Research Program
; Lake
; Stream
; Community
; Invertebrates
; Plankton
; NWTLTER
AB None
$
CL 0143
AU Bushnell, J.H.
; Butler, N.M.
DT 1984
TI Plankton data from the Green Lakes Valley Flowage System
SO University of Colorado Long-Term Ecological Research Data Report, 85/3. 34
 pp.
DE Data report
; Taxonomy & systematics
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Lake
; Stream
; Distribution
; Plankton
AB None
$
CL 0146
AU Bushnell, J.H.
; Haney, B.J.
; Wahle, B.M.
DT 1984
TI Benthos data from the Green Lakes Valley Flowage System
SO University of Colorado Long-Term Ecological Research Data Report, 84/1. 22
 pp.
DE Data report
; Ecology
; Long-Term Ecological Research Program
; Lake
; Stream
; Community
; Invertebrates
; Plankton
AB None
$
CL 0145
AU Bushnell, J.H.
; Haney, B.J.
DT 1983
TI Benthic invertebrate community patterns in an alpine flowage system
SO Journal Colorado-Wyoming Academy of Sciences, 15(1):15-16.Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Lake
; Stream
; Community
; Invertebrates
; Plankton
AB None
$
CL 0146a
AU Busse, S.
DT 1986
TI Bodengeographisch-geookologische Untersuchungen in der subalpinen und
 alpinen Hohenstufe der Colorado Front Range (USA) unter Berucksichtigung des
 aktuellen Problems der sauren Niederschlage
SO Diplomarbeit thesis, Rheinische Friedrich-Wilhelms-Universitaet, Bonn. 147
 pp
DE article
; geoecology
; Mountain Research Station
; Indian Peaks Region
; soil
; altitude
; precipitation
; acid deposition
AB None
$
CL 0147
AU Butler, N.M.
; Kaiser, W.D.
DT 1983
TI Zooplankton communities in an alpine watershed
SO Journal Colorado-Wyoming Academy of Sciences, 15(1): 15 Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Lake
; Stream
; Community
; Invertebrates
; Plankton
AB None
$
CL1468
AU Buttenfield, B.P.
DT 2001
TI Mapping ecological uncertainty
SO Chapter 6 In: Hunsaker, C., Goodchild, M.F., Friedl, M. and Case, T. (eds.) Uncertainty in spatial data for ecological analyses. New York: Springer-Verlag
DE GIS
AB None
$
CL 1430
AU Buttenfield, B.P.
; Tsou, M.
DT 2000
TI Distribution an internet-based GIS to remote college classrooms
SO Proceedings, ESRI user conference, San Diego, California. 
DE none
AB Teachers in many parts of rural Colorado have an interest in adopting GIS technology but lack technical resources and expertise to set up and maintain the application software. This paper re
2000
ports a Colorado University showcase project to implement Internet-based GIS training modules for distance learning. The modules are embedded with online assessment tools, allowing a dual project focus on GIS content and on strategies for automated user assessment. The modules are delivered on an Internet Map Server and will be assessed in lower- and upper-division college classes this spring. The paper will report on the mechanics, the module content and the strategies.    $
CL 1297
AU Caine N.
DT 1995
TI Temporal trends in the quality of streamwater in an alpine environment:
 Green Lakes Valley, Colorado Front Range, U.S.A. 
SO Geografiska Annaler 77A (4):207-220
DE NWTLTER
; alpine hydrology
; stream acidification
; acid neutralizing capacity
; Colorado Front Range
; Green Lakes Valley
AB Green Lakes Valley is a high (3500m elevation), mid-continental
 drainage at relatively low latitude (40 degrees N) which appears to
 have been influenced by a variety of environmental changes in the past
 half-century. Important among these have been increased rates of 
 deposition of strong acid anoins from the atmosphere and a corresponding
 tendency toward acidification of surface waters. In response, a declining
 trend in acid neutralizing capacity (ANC) and in the pH of streamwater
 in the basin has occurred in the past 25 years. This trend is most marked
 at the highest (most alpine) elevations in the basin where there is
 little soil and vegetation cover but remains detectable, if less marked,
 at all elevations down to treeline (3250m). It suggests that acidification
 (defined as a loss of ANC) of surface water will be widespread in the
 basin within a decade.
$
CL 1302
AU Caine N.
DT 1996
TI Streamflow patterns in the alpine environment of North Boulder Creek,
 Colorado Front Range
SO Zeitschrift Geomorphologie 104: 27-42
DE NWTLTER
; streamflow
; North Boulder Creek
; hydrology
; snowmelt
; discharge
AB Streamflows from the Colorado alpine are an important contribution to
 the water resources of the state and are generated almost entirely by 
 melting of the seasonal snow cover. As such, they are remarkably 
 predictable, following the temporal patterns of solar radiation which
 drives snowmelt. Within the 7 square km  Green Lakes Valley, the diurnal 
 flow cycle is most consistently developed in headwater sub-basins and is
 superimposed upon the predominant annual cycle. Together, these
 snowmelt-driven cycles account for up to 90% of the variability in
 streamflow. Summer rainfall, though occasionally intense, has relatively
 little hydrologic influence in this system.
$
CL 0148
AU Caine, J.M.
DT 1982
TI Sources of dissolved humic substances of a subalpine bog in the Boulder
 Watershed, Colorado
SO M.S. thesis, University of Colorado, Boulder. 85 pp.
DE Thesis
; Hydrology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Acid Deposition
; Mining
; Precipitation
; Snow
; Stream
; Watershed
; Water
AB None
$
CL 0153
AU Caine, N.
DT 1984
TI Elevational contrasts in contemporary geomorphic activity in the Colorado
 Front Range
SO Studia Geomorphologica Carpatho-Balcanica, 18:5-31
DE Geomorphology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Altitude
; NWTLTER
AB None
$
CL 0148d
AU Caine, N.
; Thurman, E.M.
DT 1990
TI Temporal and spatial variations in the solute content of an alpine stream,
 Colorado Front Range
SO Geomorphology 4:55-72
DE article
; Hydrology
; Long-Term Ecological Research Program
; Niwot Ridge
; chemistry
; stream
; watershed
; NWTLTER
AB None
$
CL 1268 
AU Caine, N.
DT 1995
TI Snowpack influences on geomorphic processes in Green Lakes Valley, 
 Colorado Front Range
SO Geographical Journal 161:55-68
DE NWTLTER
; Green Lakes Valley
; USA
; Colorado Front Range
; alpine erosion
; snow cover
; geomorphology
AB In the alpine catchment of Green Lakes Valley, the great 
 variability in snow distribution is an important influence on 
 environmental conditions. The snow cover has relatively little direct 
 effect on geomorphic processes: avalanches of wet snow in spring 
 transport small volumes of debris to the valley floor and boulders 
 are shifted locally in small sub-nival pavements. Indirectly, the 
 influence of snow patterns on erosion is much greater. By changing 
 the surface topography, it facilitates sediment transport across the 
 tundra; through its control of hydrologic responses, its meltwater 
 mediates sediment and solute movement; and by controlling the biota, 
 it defines the source areas from which most sediments and solutes are 
 derived.
$
CL 0148b
AU Caine, N.
DT 1989
TI Hydrographic separation in a small alpine basin based on inorganic solute
 concentrations
SO Journal of Hydrology 112:89-101
DE article
; Hydrology
; Long-Term Ecological Research Program
; Niwot Ridge
; chemistry
; snow
; water
; NWTLTER
AB None
$
CL 1222
AU Caine, N.
DT 1992
TI Spatial patterns of geochemical denudation in a Colorado alpine environment
SO Pp. 63-88 In: Dixon, J.C., and A.D. Abrahams (eds.). Periglacial
 Geomorphology. Chichester: John Wiley and Sons Ltd. 354 pp
DE NWTLTER
; geomorphology
; stream water quality
; discharge
; solute yields
; suspended sediment
; Green Lakes Valley
AB Up to ten years of discharge and water quality records from Green Lakes
 Valley, a nonglacierized alpine catchment in the Colorado Front Range, define
 a consistent spatial pattern of geochemical denudation. The solute yields
 suggested by these records are generally low (between 5 and 20 g/m2/yr) but
 exceed by an order of magnitude rates of suspended sediment transport in the
 basin. Geochemical denudation rates vary spatially, being highest in
 subcatchments where winter snow accumulation is greatest. Within these
 subcatchments, spatial variability of at least the same magnitude may be
 predicted from the local water budget and is supported by rock weathering
 studies (e.g., Thorn, C.E. 1975. Influence of late-lying snow on rock-
 weathering rinds. Arctic and Alpine Research 7: 373-378.). These results
 suggest that solute removal from sites of greatest snow accumulation is
 important in maintaining the hollows associated with nivation and similar
 forms in mountain terrain.
$
CL 1220
AU Caine, N.
DT 1992
TI Modulation of the diurnal streamflow response by the seasonal snowcover of
 an alpine basin
SO Journal of Hydrology 137: 245-260
DE NWTLTER
; streamflow
; discharge
; Martinelli Basin
; snowmelt
; hydrology
; hydraulic conductivity
AB A 10-year record of streamflow from the 8-ha Martinelli Basin in the
 Colorado Front Range is dominated by snowmelt- produced flows. During the main
 part of the May-September flow season, the flows develop a marked 24-h cycle
 which often accounts for more than 50% of their variance, after removal of the
 seasonal trend. The amplitude and phase of this cycle vary in a similar
 fashion each year, showing a reduced amplitude and a forward phase shift as
 the summer progresses. These changes are explained by the reduction in the
 area of snow cover and its depth during the season. The phase shift may be
 used to estimate a catchment-scale hydraulic conductivity for a melting snow
 cover, yielding values in the range of 40-80 cm/h. These are consistent with
 other estimates based upon plot and laboratory studies.
$
CL 0153a
AU Caine, N.
DT 1986
TI Sediment movement and storage in the Colorado Rocky Mountains (Niwot Ridge
 site)
SO In: Adams, J.R. (compiler), Sediment Movement at LTER Sites: Mechanics,
 Measurement, and Integration with Hydrology. University of Illinois, Illinois
 State Water Survey Contract Report 387, 39-41
DE Technical Report
; Geomorphology
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Sediment
; Sedimentology
; Water
; Watershed
; NWTLTER
AB None
$   
CL 1432
AU Caine, N.
DT 2001
TI Geomorphic systems of Green Lakes Valley
SO Chapter 4 In: Bowman, W.D. and T.R. Seastedt. (eds.) S
2000
tructure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 0153d
AU Caine, N.
; Caine, J.
; Thurman, E.M.
DT 1987
TI Water quality data from the Green Lakes Valley, 1982-1986
SO University of Colorado Long-Term Ecological Research Data Report 87/5. 46 pp
DE Data Report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Stream
AB None
$
CL 0148c
AU Caine, N.
; Swanson, F.J.
TI Geomorphic coupling of hillside and channel systems in two small mountain
 basins
SO Zeitschrift fuer Geomorphologie 33(2):189-203
DT 1989
DE article
; Hydrology
; Long-Term Ecological Research Program
; Niwot Ridge
; chemistry
; water
; watershed
; NWTLTER
AB None
$
CL 0153b
AU Caine, N.
TI Sediment movement and storage on alpine slopes in the Colorado Rocky
 Mountains
DT 1986
SO In: Abrahams, A.D., (ed.), Hillslope Processes. Binghampton Symposium in
 Geomorphology: International Series No. 16. Boston: Allen and Unwin, 115-137
DE Hydrology
; Sedimentology
; Long-Term Ecological Research Program
; Water
; Boulder Watershed and Rainbow Lakes
; Glacier
; Landslide
; Sediment
; Snow
; Soils
; Stream
; Watershed
; NWTLTER
AB None
$
CL 0154
AU Caine, N.
; Furbish, D.J.
; Harbor, J.M.
DT 1985
TI Interactions between geomorphic processes and vegetation in the alpine
 tundra of the Colorado Rocky Mountains
SO Bulletin of Ecological Society America, 66(2):150 Abstract
DE Abstract
; Ecology
; Geomorphology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Plant
AB None
$
CL 0157
AU Caine, N.
; Thurman, E.M.
; Furbish, D.J.
; Moses, T.A.
DT 1983
TI Water quality data from the Green Lakes Valley, 1981-1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/7. 47
 pp.
DE Data report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Lake
; Stream
; Water
AB None
$
CL1473
AU Caine, N.
DT 2002
TI Declining ice thickness on an alpine lake is generated by increased winter precipitation
SO Climatic Change v. 54 pp. 463-470
DE None
AB None
$
CL 0155
AU Caine, N.
; Furbish, D.J.
; Moses, T.A.
DT 1983
TI Stream-flow data from the Green Lakes Valley, 1981-1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/2. 56
 pp.
DE Data report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Stream
; Water
AB None
$
CL 0153c
AU Caine, N.
; Buchanan, L.
DT 1987
TI Streamflow data from the Green Lakes Valley, 1981-1986
SO University of Colorado Long-Term Ecological Research Data Report 87/4. 31 pp
DE Data Report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Lake
; Stream
; Water
; Watershed
AB None
$
CL 1221
AU Caine, N.
DT 1992
TI Sediment transfer on the floor of Martinelli snowpatch, Colorado Front
 Range, U.S.A.
SO Geografiska Annaler 74A (2-3): 133-144
DE NWTLTER
; sediment yields
; sediment budget
; nivation processes
; alpine denudation
; Colorado Front Range
; Martinelli Basin
; geomorphology
AB The Martinelli snowpatch occupies a shallow hollow on the south side of
 Niwot Ridge, Colorado Front Range. A relatively long-term (up to 10 years)
 record of sediment movement onto and across its floor and of sediment yields
 from its catchment basin is reported here. This record shows sediment fluxes
 which are highly variable in time but which define a spatially consistent
 pattern involving high flux rates (up to 1500/g/m/yr) onto the basin floor at
 its head and slower rates of downslope movement from there. The small stream
 channels in the basin have been stable over the period of study and show an
 approximately balanced budget of silt and clay sized sediments. They, and the
 basin floor, are accumulating coarser sediment at a slow rate (<1 mm/yr) which
 suggests long-term landscape development by a decay model (Thornes, J.B., and
 D. Brunsden. 1977. Geomorphology and time. London: Methuen, 208 pp.). This
 would require that the "nivation hollow" form tends to be removed under
 present conditions, though it does not take solutional processes into account.
$
CL 0148a
AU Caine, N.
DT 1989
TI Diurnal variations in the inorganic solute content of water draining from an
 alpine snowpatch
SO Catena, 16(2):153-162
DE article
; hydrology
; Long-Term Ecological Research
; Boulder City Watershed
; chemistry
; snow
; water
AB None
$
CL 0146b
AU Caine, N.
TI Diurnal variations in the inorganic solute content of water draining from an
 alpine snowpatch
DT 1989
SO Catena, 16(2):153-162
DE article
; hydrology
; Long-Term Ecological Research
; Boulder City Watershed
; chemistry
; snow
; water
; NWTLTER
AB None
$
CL 0156
AU Caine, N. (ed.)
; Swanson, F. (ed.)
DT 1983
TI Report of Long-Term Ecological Research Workshop on disturbance regimes of
 ecosystems
SO University of Colorado Long-term Ecological Research Working Paper, 83/6. 48
 pp.
DE Data report
; Geomorphology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Disturbances
AB None
$
CL 0152
AU Caine, T.N.
DT 1982
TI Water and sediment flows in the Green Lakes Valley, Colorado Front Range
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine.
 University  of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper, 37,13-22
DE Hydrology
; Sedimentology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Snow
; Soil
; Stream
; NWTLTER
AB None
$
CL 0151
AU Caine, T.N.
DT 1980
TI Glaciology and hydrology: overview
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 199-201
DE Glaciology
; Hydrology
; Institute of Arctic and Alpine Research
; Snow
; Soil
; Stream
; Lake
; Watershed
; Climate - Discussion of
AB None
$
CL 0149
AU Caine, T.N.
DT 1974
TI The geomorphic processes of the alpine environment
SO In: Ives, J.D. and Barry, R.G. (eds.), Arctic and Alpine Environments.
 London: Methuen, 721-748
DE Geomorphology
; Institute of Arctic and Alpine Research
; Snow
; Soil
; Stream
; Watershed
; Climate - Discussion of
AB None
$
CL 1519
AU Calanni, J.
; Berg, E.
; Wood, W.
; Mangis, D.
; Boyce, R.
; Weathers, W.
; Sievering, H. 
DT 1999
TI Atmospheric nitrogen deposition at a conifer forest: response of free amino acids in engelmann spruce needles 
SO Environmental Pollution v. 105 pp.79-89
DE NWTLTER
; arginine
; free amino acids
; nitrogen deposition
; Engelmann spruce
AB Recent increases of nitrogen (N) deposition to forest ecosystems have had a variety of effects on plant species including mineral imbalance, growth disturbance and the accumulation of foliar-free amino acids. The purpose of this study was to determine the existence and degree of correlation between variable atmospheric nitrogen deposition and the concentrations of foliar free amino acids in Engelmann spruce (Picea engelmannii). Needle samples were collected during July and August of 1996 from a site iri the Colorado Rocky Mountains that has large diurnal variations in atmospheric nitrogen deposition and receives approximately 4-8 kg N ha(-1) year(-1) total deposition. Amino acid concentrations were quantified with foliar % N also determined. Atmospheric nitrogen concentrations of gaseous HNO3 and NH3, as well as particulate NH4+ and NO3-, were determined simultaneously with needle sampling, and were subsequently converted to atmospheric N flux estimates. Foliar concentrations of arginine (July intensive) and glutamic acid (August intensive) in adult trees showed strong positive correlations with variations in atmospheric N flux, dominated by nitric acid, after a 4 +/- 2 h time delay. The results of this study support previous work that suggest that arginine may serve as an indicator of atmospheric N deposition. More importantly, however, this study has shown that foliar amino acid responses to atmospheri
2000
c N flux (especially arginine) may occur after approximately a 4 +/- 2 h time delay.
$
CL 0160
AU Caldwell, M.
; Tieszen, L.L.
; Fareed, M.
DT 1972
TI Comparative Barrow and Niwot Ridge canopy structure
SO In: Bowen, S. (ed.), Proceedings 1972 Tundra Biome Symposium, Lake
 Wilderness Center, University of Washington, 3-5 April 1972, U.S. IBP Tundra 
 Biome, 22-28
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Community
; Diversity
AB None
$
CL 0159
AU Caldwell, M.M.
; Johnson, D.A.
; Fareed, M.
; Tieszen, L.L.
; Moore, R.T.
; Ehleringer, J.
DT 1973
TI Gas exchange of alpine tundra species
SO U.S. Tundra Biome Data Report, 73-16. 41 pp.
DE Data report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Carbon Dioxide
; Metabolism
; Angiosperms
AB None
$
CL 0161
AU Caldwell, M.M.
; Tieszen, L.L.
; Fareed, M.
DT 1974
TI The canopy structure of tundra plant communities at Barrow, Alaska and Niwot
 Ridge, Colorado
SO Arctic and Alpine Research, 6:151-159. Reprinted in: Ives, J.D. (ed.), 1980,
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 403-411
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Tracheophytes
; Community
; Diversity
AB None
$
CL 0158a
AU Caldwell, M.M.
; Johnson, D.A.
; Fareed, M.
DT 1978
TI Constraints on Tundra Productivity: Photosynthetic Capacity in Relation to
 Solar Radiation Utilization and Water Stress in Arctic and Alpine Tundras
SO In: Tieszen, L.L. (ed.), Vegetation and Production Ecology of an Alaskan
 Arctic Tundra, Ecological Studies 29. New York: Springer-Verlag New York Inc.,
 323-341
DE Biology
; Ecology
; U.S. International Biological Programme
; Saddle (Niwot Ridge)
; Angiosperms
; Insolation
; Water
; Growth (Development)
; Photosynthesis
; Physiological
; Productivity
AB None
$
CL 0158
AU Caldwell, M.M.
DT 1968
TI Solar ultraviolet radiation as an ecological factor for alpine plants
SO Ecological Monographs, 38:243-268
DE Climatology
; Institute of Arctic and Alpine Research
; Ecology
; Niwot Ridge
; Insolation
; Bioenergetics
; Plant
AB None
$
CL 0166
AU Carey, C.
; Hoyt, D.F.
; Bucher, T.L.
; Larson, D.L.
DT 1984
TI Eggshell conductances of avian eggs at different altitudes
SO In: Seymour, R.S., (ed.) Respiration and Metabolism of Embryonic
 Vertebrates. Dordrecht, Nederlands: D.W. Junk Publishers, 259-270
DE Ecology
; Institute of Arctic and Alpine Research
; Mountain Research Station - Location
; Altitude
; Physiological
; Birds
AB None
$
CL 0167
AU Carroll, T.
DT 1974
TI Relative age dating techniques and a late Quaternary chronology, Arikaree
 Cirque, Colorado
SO Geology, 2:321-325. Reprinted in: Ives, J.D. (ed.), 1980: Geoecology of the
 Colorado Front Range. Boulder: Westview Press, 51-55
DE Geomorphology
; Chronology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Glacier
; Growth (Development)
; Lichens
AB None
$
CL 0171a
AU Carroll, T.
; Caine, N.
DT 1974
TI Volume and role of stream discharge from an alpine snowpack
SO In: Lewis, G.D. (compiler), The Eisenhower Consortium for Western
 Environmental Forestry Research: Research Highlights, 1972-1980. Eisenhower
 Consortium Bulletin 8, III-4
DE Abstract
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Snow
; Stream
; Water
; Watershed
AB None
$
CL 0169
AU Carroll, T.
DT 1976
TI Hydrology of an alpine basin in the Colorado Front Range
SO Proceedings 44th Annual Western Snow Conference, Calgary, Alberta, April
 20-22. 12 pp.
DE Hydrology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Lake
; Precipitation
; Snow
; Stream
; Water
AB None
$
CL 0171
AU Carroll, T.
DT 1980
TI An estimate of watershed efficiency for a Colorado alpine basin
SO In: Ives, J.D. (ed.), 1980: Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 229-240
DE Hydrology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Lake
; Precipitation
; Snow
; Stream
; Water
; Watershed
AB None
$
CL 0168
AU Carroll, T.R.
DT 1974
TI The water budget of an alpine catchment in Central Colorado
SO M.A thesis, University of Colorado, Boulder. 124 pp.
DE Thesis
; Hydrology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Lake
; Precipitation
; Snow
; Stream
AB None
$
CL 0170
AU Carroll, T.R.
DT 1977
TI Statistical analysis of the liquid water distribution in a high altitude
 snowpack
SO Ph.D. dissertation, University of Colorado, Boulder. 70 pp.
DE Dissertation
; Technique
; Hydrology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Precipitation
; Snow
; Water
AB None
$
CL 0175
AU Chapin, F.S., III
; Chapin, M.C.
DT 1981
TI Ecotypic differentiation of growth processes in Carex aquatilis along
 latitudinal and local gradients
SO Ecology, 62:1000-1009
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Genetics
; Altitude
; Latitude
; Growth (Development)
AB None
$
CL 0174
AU Chapin, F.S., III
DT 1981
TI Field measurements of growth and phosphate absorption in Carexa quatilis
 along a latitudinal gradient
SO Arctic and Alpine Research, 13:83-94
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Altitude
; Biochemical
; Physiological
; Growth (Development)
; Nutrients
; Angiosperms
AB None
$
CL 0176
AU Chapman, J.E.
DT 1969
TI Ecology of Polycelis coronata in some Colorado habitats
SO Ph.D. dissertation, University of Colorado, Boulder. 157 pp.
DE Dissertation
; Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Mountain Research Station - Location
; Invertebrates
; Lake
; Stream
; Distribution
AB None
$
CL 0177
AU Charles, T.J.
DT 1983
TI Development of a reservoir operations package for inclusion into the
 precipitation-runoff-modeling-system based upon specific site conditions
 within the Boulder Watershed
SO M.S. thesis, University of Colorado, Boulder. 180 pp.
DE Thesis
; Model
; Hydrology
; Management
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Lake
; Precipitation
; Snow
; Stream
; Watershed
; Water
; Climate - Discussion of
; NWTLTER
AB None
$
CL 1357
AU Chase, T.N.
; Pielke. R.A.
; Kittel, T.G.F.
; Baron, J.S.
; Stohlgren, T.J.
DT 1999
TI Potential impacts on Colorado Rocky Mountain weather and climate due to land use
 changes on the adjacent Great Plains
SO Journal of Geophysical Research 104:16673-16690
DE NWTLTER
; meteorology
; temperature
; precipitation
AB Evidence from both meteorological stations and vegetational successional studies 
 suggests that summer temperatures are decreasing in the mountain-plain system 
 in northeast Colorado, particularly since the early 1980s. These trends are 
 coincident with large changes in regional land cover. Trends in global, Northern 
 Hemisphere and continental surface temperatures over the same period are insignificant. 
 These observations suggest that changes in the climate of this mountain-plain system 
 may be, in some part, a result of localized forcing mechanisms. In this study the 
 effects of land use change on the northern Colorado plains, where large regions of 
 grasslands have been transformed into both dry and irrigated agricultural lands, on 
 regional weather is examined in an effort to understand this local deviation from 
 larger-scale trends. We find with high-resolution numerical simulations of a 3-day 
 summer period using a regional atmospheric-land surface model that replacing grasslands
 with irrigated and dry farmland can have impacts on regional weather and therefore 
 climate which are not limited to regions of direct forcing. Higher elevations remote 
 from regions of land use change are affected as well. Specifically, cases with altered 
 landcover had cooler, moister boundary layers, and
2000
 diminished low-level upslope winds 
 over portions of the plains. At higher elevations, temperatures also were lower as 
 was low-level convergence. Precipitation and cloud cover were substantially affected 
 in mountain regions. We advance the hypothesis that observed land use changes may 
 have already had a role in explaining part of the observed climate record in the 
 northern Colorado mountain-plain system.
$
CL 1570
AU Clark, B.R.
; Hartley, S.E.
; Suding, K.N.
; de Mazancourt, C.
DT 2005
TI The effect of recycling on plant competitive hierarchies
SO American Naturalist vol. 165(6) pp. 609-622
DE NWTLTER
; nitrogen
; recycling
; model
; R*
; resource competition
; mineralization
AB Evidence from field studies suggests that some plant species enhance their persistence by reinforcing patterns of N availability through differences in litter quality. Using mathematical models of nutrient flow, we explore whether and how recycling affects plant growth, competition, and coexistence and whether it leads to positive feedbacks. Two mechanisms are considered: the ability of plants to access two forms of soil N, complex ( e. g., organic) and simple (e.g., nitrate), and the effect of density-dependent limitation of growth. Except in the trivial case of limitation by N in one form without density dependence, differences in litter quality can prevent the establishment of competitors. Feedback can, conversely, facilitate the invasion of competitors. At equilibrium, the rate of decomposition does not affect the outcome of competition. Species affect their long-term persistence if they alter the fraction of nitrogen that is returned to the soil and becomes available for plant uptake. Increasing the fraction of N that is recycled favors specialists in complex nitrogen and species that suppress the growth of others at high nitrogen availability. Increasing the rate of microbial decomposition of complex nitrogen favors specialists in simple nitrogen.
$
CL 0180
AU Clark, J.M.
; Marr, J.W.
DT 1966
TI Insolation and other environment factors during 1965 in three ecological
 regions in the Front Range, Colorado
SO Final Report on Contract DA49-092-AR046.
DE Data report
; Climatology
; Mountain Research Station - Affiliation
; A-1 Climate Station
; Insolation
; Climate - Data Included
AB None
$
CL 0182
AU Clark, J.M.
; Wells, C.
DT 1973
TI An interface system for meteorological data using the ERTS data collection
 platform
SO Arctic and Alpine Research, 5:151-154
DE Technique
; Climatology
; Remote sensing
; Mountain Research Station - Affiliation
; Niwot Ridge
AB None
$
CL 0181
AU Clark, J.M.
; Peterson, E.B.
DT 1967
TI Insolation in relation to cloud characteristics in the Colorado Front Range
SO In: Wright, H.E., Jr., and Osburn, W.H. (eds.), Arctic and Alpine
 Environments. Bloomington: Indiana University Press, 3-11
DE Climatology
; Mountain Research Station - Affiliation
; A-1 Climate Station
; Insolation
; Climate - Data Included
AB None
$
CL 1320
AU Cline D.W.
DT 1997
TI Effect of seasonality of snow accumulation and melt on snow surface 
 energy exchanges at a continental alpine site.
SO Journal of Applied Meteorology. 36 (1):22-41.
DE NWTLTER
; snowmelt
; snow accumulation
; net radiation
; heat fluxes
; energy exchange
AB Snow surface energy exchange and snowmelt were measured during
 the 1994 and 1995 snowmelt seasons at an alpine site in the Colorado
 Front Range (3517m MSL, 40 degrees 30 minutes North, 105 degrees
 35 minutes West). Following a maximum accumulation of 0.49m snow
 water equivalence (SWE), the 1994 snowmelt season began on 5 May
 and lasted 32 days until 6 June. In contrast, the 1995 maximum 
 accumulation of 1.31m SWE did not occur until 1 June, and the snowmelt
 season lasted 45 days until July 16. Thus, a nearly threefold larger
 snowpack ablated in only 41% more time in the later 1995 snowmelt
 season. In 1994, net radiation accounted for 75% of the energy available
 to melt, and sensible and latent heat fluxes accounted for the remaining
 25%. During the 1995 snowmelt season the mean air temperature was warmer
 (+1.3 degrees C) and the mean specific humidity was greater (+0.6 g/kg)
 than during the 1994 snowmelt season. As a result, in 1995, sensible and
 latent heat fluxes accounted for 54% of the energy for snowmelt and net
 radiation accounted for only 46%. Midday maximum snowmelt rates were
 approximately equal in 1994 and 1995; the overall more rapid 1995 melt
 rate was due to the frequent occurrence of nocturnal melting, which did
 not occur in 1994. The large differences between these two snowmelt
 seasons provide analogies for understanding regional variability of
 snowmelt processes and for understanding alpine snowmelt response to climate
 variability and change.
$
CL 1321
AU Cline D.W.
DT 1997
TI Snow surface energy exchanges and snowmelt at a continental, midlatitude
 Alpine site. 
SO Water Resources Research. 33 (4):689-701.
DE NWTLTER
; snowmelt
; energy balance
; energy fluxes
; SNTHERM model
AB The objectives of this study were to measure and evaluate the energy
 balance of a continental, midlatitude alpine snowpack during spring
 snowmelt conditions, to relate variations in the energy budget and
 snowmelt to synoptic weather patterns, and to evaluate the performance
 of a point energy and mass balance model of a snow cover (SNTHERM) in
 alpine conditions. The investigation was conducted during the 1994
 snowmelt season at Niwot Ridge (3517m above sea level (asl); 40 degrees
 3 minutes North, 105 degrees 35 minutes West) in the Colorado Front
 Range. Net radiative fluxes and net turbulent fluxes respectively 
 provided 75% and 25% of the total energy available for the snowmelt
 during the season. Sublimation losses were limited to only 4% of the 
 initial snow water equivalence at the site. The largest energy available
 for snowmelt was associated with a ridge in the upper airflow over the
 central and southern Rocky Mountains that permitted warmer air into the
 region. Using measured data from the study site, the SNTHERM model estimated
 the disappearance of the snowpack just 3 days earlier than the observed
 42-day ablation period.
$
CL 1278
AU Cline, D.
DT 1995
TI Snow surface energy exchanges and snowmelt at a continental alpine site
SO Pp. 157-166 In Tonnessen, K. A., M. W. Williams, and M. Tranter (eds.).
 Biogeochemistry of Seasonally Snow Covered Basins. International
 Association of Hydrological Sciences, Wallingford, UK, IAHS-AIHS
 Publication no. 228. 465 pp.
DE NWTLTER
; energy balance
; snow
; snowmelt
; Niwot Ridge
; radiative energy flux
; turbulent energy flux
; soil energy flux
; albedo
; net radiation
; latent heat
; sensible heat
AB The energy balance of an alpine snowpack was studied during the 1994
 snowmelt season at Niwot Ridge (3517 m a.s.l., 40 degrees 03 minutes N,
 105 degrees 35 minutes W), an alpine site in the Colorado Front Range.
 Radiative, turbulent, and soil energy fluxes, and snowmelt were
 measured. Prior to the onset of snowmelt, the high albedo of the snow-
 pack (~ 90%) coupled with nearly constant longwave losses caused the
 daytime maximum net radiation to remain below 100 W/m. As the snow
 albedo decreased with age, the daytime net radiation receipts began to
 increase, and melt began. Little additional snow accumulation 
 occurred following the beginning of snowmelt, so the albedo continued
 to decrease to a seasonal minimum of less than 60%. Consequently, 
 daytime maximum net radiation increased during this period, and a 
 typical diurnal pattern of daytime snowmelt ensued. Net radiative 
 fluxes provided 75% of the total energy available for snowmelt during
 the season. During this period, turbulent fluxes were of small
 magnitude and usually of opposite sign, with latent heat losses and
 slightly larger sensible heat gains. The net energy supplied by 
 turbulent sources was 25% of the seasonal total.
$
CL 1253
AU Cline, D.W.
DT 1992
TI Modeling the redistribution of snow in alpine areas 
2000
using geographic
 information processing techniques
SO M.A. thesis, University of Colorado, Boulder. 206 pp
DE NWTLTER
; Niwot Ridge
; modeling
; snow redistribution
AB None
$
CL 1282
AU Cline, D.W.
DT 1995
TI Studies supporting the development of spatially-distributed, physically 
 based snowmelt models for continental alpine areas
SO Ph.D. dissertation, University of Colorado, Boulder. 186 pp.
DE NWTLTER
; Niwot Ridge
; snowmelt
; modeling
; energy exchange
; climate
AB The principal goal of this research is to improve understanding of the 
 spatial distribution and temporal patterns of alpine snowmelt under the 
 current climate regime. The material contained in this report is intended 
 to support the development of spatially-distributed, physically-based 
 snowmelt modeling for continental alpine regions. The investigation 
 includes 1) a baseline field study of snow surface energy exchanges and 
 boundary layer climate at an alpine site in the Colorado Front Range; 
 2) a systematic analysis of the sources and magnitudes of uncertainty 
 associated with existing process models describing snowpack dynamics; and 
 3) an analysis of the sensitivity of a point energy and mass balance model 
 of a snowpack to such uncertainty. This study has provided important 
 baseline information concerning snow surface energy exchanges and snowmelt 
 at a continental alpine site. A "permanent" energy balance monitoring site 
 has been installed on Niwot Ridge, which with proper maintenance should 
 continue to provide year-round energy balance information for many years.  
 Relationships between energy exchanges at a point and larger scale synoptic 
 weather characteristics were shown, and these results show promising 
 potential for improved understanding of snowmelt at regional scales. These 
 types of measurements and analyses are viewed as critical for future 
 development of spatially-distributed, physically-based snowmelt modeling 
 efforts, but an additional critical factor which is all too often 
 overlooked is the uncertainty that is associated with spatial estimates of
 snowmelt variables and parameters. Therefore this study also examined the 
 sources and magnitudes of uncertainty that might be expected in modeling 
 snowmelt in relatively small alpine basins of modest relief. A Monte Carlo 
 simulation program was developed for SNTHERM.89, a detailed point energy 
 and mass balance model of a snowcover, to explore what effects spatial 
 uncertainty may have on snowmelt estimates. Monte Carlo simulations showed 
 that, without interaction between variables, the effect of introducing 
 uncertainty to a single variable was small. However, uncertainty in 
 modeled snowmelt clearly increases with the duration of the simulation.
$
CL 0189
AU Cockerell, T.D.A.
DT 1915
TI Some plants from the vicinity of the Arapahoe Glacier
SO Torreya, 15(9):202-205
DE Biology
; Taxonomy & systematics
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Plant
; History
AB None
$
CL 0191
AU Cofer, C.
DT 1972
TI Differences in ablation of three adjacent alpine glaciers, Indian Peaks
 region, Front Range, Colorado
SO Arctic and Alpine Research, 4(4):349-353. Reprinted in: Ives, J.D. (ed.),
 1980: Geoecology of the Colorado Front Range. Boulder: Westview Press, 
 224-228
DE Climatology
; Glaciology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Insolation
; Climate - Data Included
; Glacier
AB None
$
CL 1315
AU Colores, G.M.
; Schmidt, S.K.
; Fisk, M.C.
DT 1996
TI Estimating the biomass of microbial functional groups using rates of
 growth-related soil respiration
SO Soil Biology and Biochemistry 28(12):1569-1577
DE NWTLTER
; biomass
; microbes
; soil respiration
; SIGR model
; SIR model
AB We developed a simple method that can be used to estimate the biomass and 
 growth rates of microbial functional groups in soil. The method is derived 
 from basic principles and can be used to estimate the biomass of organisms
 that can mineralize specific substrates added to soil. We adapted the substrate-
 induced growth-response (SIGR) model that was originally used to analyze curves
 of substrate disappearance or cumulative CO2 production. The present model 
 utilizes data describing the rate of CO2 production from substrates added to
 soil. We used two unique systems to demonstrate the applicability of this
 method. In one test of the model we added glucose to alpine tundra soil to 
 estimate the biomass that could respond to a labile carbon source. We also 
 derived biomass estimates from a widely used substrate-induced respiration
 (SIR) model for the same soil. Overall the SIGR method yielded conservative
 biomass estimates (mean = 194 micrograms C per gram of soil) when compared
 to the SIR estimates (mean = 436 micrograms C per gram of soil). In the second
 test we used a soil to which a known biomass of a specific functional group
 (i.e. pentachlorophenol-mineralizers) was added. In this case the SIGR method
 also gave a conservative estimate of 0.05 micro grams C per gram compared to
 a death-rate adjusted value of 0.11 micro grams C per gram for the actual inoculum
 added to the soil. The SIGR model also estimated maximum specific growth rates
 (0.11-0.12 /h) similar to those measured in independent experiments (0.09/h)
 for the Sphingomonas sp. that was added to the soil. Using our model we were able
 to obtain biomass estimates and growth rates for microbial functional groups
 without using calibrations needed for other physiological methods. Overall,
 the SIGR approach gives conservative estimates of the active biomass that
 can mineralize specific carbon substrates added to soil.
$
CL 1421  
AU Colores, G.M.
; Schmidt, S.K.
DT 1999
TI Colonization of contaminated soil by an introduced bacterium: effects of initial peentachlorophenol levels on the survival of Sphingomonas chlorophenolica strain RA2  
SO Journal of Industrial Microbiology and Biotechnology. 31: 1649-1655
DE None
AB None 
$
CL 1387
AU Conley, A.H.
; Holland, E.A.
; Seastedt, T.R.
; Parton, W.J.
DT 2000
TI Simulation of carbon and nitrogen cycling in an alpine tundra
SO Arctic, Antarctic, and Alpine Research. 32: 147-154.
DE None
AB None
$
CL 1374
AU Conley, A.H.
; Holland, E.A.
; Seastedt, T.R.
; Parton, W.J.
DT 2000
TI Simulation of carbon and nitrogen cycling in an alpine tundra
SO Arctic, Antarctic, and Alpine Research 32:147-154
DE NWTLTER
; nitrogen
; carbon
; CENTURY model
AB Simulations of an alpine tundra ecosystem using the CENTURY ecosystem
 model were conducted to test model descriptions of carbon and nitrogen
 cycling and to explore the alpine ecosystem response to physical and chemical
 components of global change. The parameterization of the alpine tundra for
 CENTURY was updated to reflect current knowledge of the site, and sensitivity
 analyses were conducted. Verification of results from a 6-yr fertilization
 experiment in the alpine tested the predictive capabilities of the parameterization.
 Simulations with increased winter precipitation and with the climate predicted
 under doubled atmospheric carbon dioxide concentrations were then conducted.
      Modifications to the parameterization necessary to describe carbon and nitrogen
 cycling included decreasing the C:N ratios of plant tissues, increasing the amount
 of nitrogen retranslocated at the end of the growing season, extending the length
 of the growing season, and lowering the rate of decomposition. The updated 
 parameterization requires 30% greater than observed inputs of net primary productivity
 to simulate observed levels of total soil carbon suggesting that soil carbon
 sequestration is not well represented in the model. Carbon and nitrogen cycling
 showed greatest sensitivity to the length of the growing season and to the
 temperature regulation of decomposition. Simulation of the nitrogen fertilization
 experiment resulted in 11% greater productivity than observed empirically,
 a reasonable verification of the u
2000
pdated parameterization. The major impact
 from increasing winter precipitation was a 30% increase in the amount of
 nitrogen in stream flow. Simulation with the climate predicted for a doubling
 of current carbon dioxide levels reduced production 10% while total soil carbon remained 
 constant. This response was largely controlled by reduced soil moisture during the
 growing season.
$
CL 0192a
AU Conway, T.J.
; Tans, P.
; Waterman, L.S.
; Thoning, K.W.
; Masarie, K.
; Gammon, R.H.
DT 1988
TI Atmospheric carbon dioxide measurements in the remote global troposphere,
 1981-1984.
SO Tellus, 40B:81-115
DE article
; NOAA - Climatic Monitoring and Diagnostics Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; carbon dioxide
AB None
$
CL 1298
AU Cortinas M.R.
; Seastedt T.R.
DT 1996
TI Short- and long-term effects of gophers (Thomomys talpoides) on soil
 organic matter dynamics in alpine tundra
SO Pedobiologia 40:162-170
DE NWTLTER
; alpine
; decomposition
; gophers
; soil carbon
AB Mounding activities of a burrowing rodent, the northern pocket gopher
 (Thomomys talpoides) on litter decomposition and soil carbon storage in 
 alpine tundra were studied in the Front Range of Colorado, USA. Plant 
 litter buried in gopher mounds lost 45% of initial mass during the first
 three months versus only 13% mass loss for surface litter. Surface litter
 decayed more rapidly during the non-growing season, and after 15 months
 values were 58% and 45% loss for buried and surface litter, respectively.
 Cumulative losses were greater for buried litter for all dates. Placement 
 of litter on north- or south-facing slopes did not affect decay rates.
 The long-term impact of chronic gopher disturbance on soil carbon storage
 was assessed by measuring soil carbon amounts beneath undisturbed and
 disturbed vegetation types. Undisturbed vegetation had lower bulk densities, 
 and significantly greater depth of surface horizons. Amounts of soil carbon 
 were not significantly different beneath gopher impacted and non-impacted 
 vegetated areas on modest slopes. However, in areas chronically disturbed 
 by gophers that lacked vegetation, carbon storage in the top 15 cm of soil 
 was reduced from 8.5 kg C per square meter to 5.5 kg C per square meter.
 Thus, chronic, frequent disturbance by gophers appears to lower the carbon 
 content and perhaps the fertility of mesic and xeric alpine meadows.
$
CL 1288
AU Coxwell, C.C.
DT 1992
TI Abiotic and biotic influences on the distribution and abundance of an alpine 
 grasshopper, Aeropedellus clavatus
SO M.S. thesis, University of Colorado, Boulder. 102 pp.
DE NWTLTER
; grasshopper
; population distribution
; population density
; Niwot Ridge
AB None
$
CL 1294
AU Coxwell, C.C.
; Bock, C.E.
DT 1995
TI Spatial variation in diurnal surface temperatures and the distribution
 and abundance of an alpine grasshopper
SO Oecologia 104:433-439
DE NWTLTER
; Niwot Ridge
; Aeropedellus clavatus
; diurnal temperature
; relative growth rate
; ecotherm
; insect distribution 
; insect abundance 
AB We studied the influence of spatial differences in diurnal surface 
 temperatures due to topography on an alpine grasshopper (Aeropedellus 
 clavatus). Temperature measurements on east- and west-facing alpine
 dry meadow slopes on Niwot Ridge in Colorado demonstrated a significant
 difference in diurnal surface temperatures between the two slopes
 throughout the growing season. A. clavatus body temperature was found to 
 be highly correlated with nearby shaded surface temperature, and individual
 grasshoppers enclosed on the two slopes had significantly higher relative
 growth rates on the warmer east slope. Temperature effects were manifest
 at the population level as well. A. clavatus was significantly more 
 abundant on the east-facing that on the west-facing slope, despite similar
 vegetation in both areas. This study contributes to our understanding
 of the myriad of factors governing insect distribution and abundance by
 attempting to integrate the physiological and ecological, abiotic and
 biotic, influences on both individuals and populations.
$
CL 1279
AU Cress, R.G.
; Williams, M.W.
; Sievering, H.
DT 1995
TI Dry depositional loading of nitrogen to an alpine snowpack, Niwot
 Ridge, Colorado
SO Pp. 33-40 In Tonnessen, K. A., M. W. Williams, and M. Tranter (eds.).
 Biogeochemistry of Seasonally Snow Covered Basins. International
 Association of Hydrological Sciences, Wallingford, UK, IAHS-AIHS
 Publication no. 228. 465 pp.
DE NWTLTER
; Niwot Ridge
; dry deposition
; nitrogen
; snow
; nitric acid
; ammonia
; deposition velocities
AB Dry deposition of nitrogen (N) to a wet and draining snowpack was 
 estimated in 1993 at Niwot Ridge in the Colorado Front Range, USA. Nitric 
 acid (HNO3), particulate NO3- (pNO3-) and particulate NH4+ (pNH4+) in the 
 ambient atmosphere were sampled using Teflon and nylon filters. Dry 
 deposition of N to snow was estimated by measuring the changes in 
 concentration and mass of NO3- and NH4+ in buckets filled with snow and 
 installed level with the snow surface; exposure times ranged from 3 to 48 
 h. Estimated deposition velocities for HNO3 ranged from 0.88 to 3.79
 cm/s (mean 1.91 cm/s); pNO3- ranged from 0.34 to 0.59 cm/s (mean 0.48 
 cm/s); and pNH4+ ranged from 0.075 to 0.296 cm/s (mean 0.221 cm/s). 
 Exposure times of 48 h were useful in measuring dry deposition fluxes; 
 shorter duration times were ineffective. Comparison of measured dry 
 deposition velocities to established velocity formulas showed good 
 correlation for HNO3; the empirical models appear to overestimate the 
 surface resistances for particulate N species.
$
CL 0199a
AU Dahms, A.
DT 1984
TI Die naturliche Vermehrung verschiedener Baumarten im oberen Waldfrenzbereich
 der Colorado Front Range in Okologischer sicht
SO Thesis, University of Munster, West Germany
DE thesis
; ecology
; Mountain Research Station
; conifers
; growth
; productivity
; timberline
; tree
AB None
$
CL 0200
AU Dailey, T.V.
DT 1981
TI Composition and quality of mountain goat diets in alpine tundra, Colorado
SO M.S. thesis, Colorado State University, Fort Collins.  116 pp.
DE Thesis
; Ecology
; D-1 Climate Station
; Artiodactyls
; Food Habits
; Nutrition
AB None
$
CL 0201
AU Daly, C.
DT 1984
TI Influence of snow persistence on the regeneration of Engelmann spruce and
 subalpine fir, Colorado Front Range
SO M.A. thesis. University of Colorado, Boulder. 157 pp.
DE Thesis
; Ecology
; University of Colorado
; Niwot Ridge
; Conifers
; Snow
; Seed
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0203
AU Daly, C.
; Shankman, D.
DT 1985
TI Seedling establishment by conifers above tree limit on Niwot Ridge, Front
 Range, Colorado, U.S.A.
SO Arctic and Alpine Research, 17:389-400
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Demography
; Conifers
; Reproduction
; NWTLTER
AB None
$
CL 0202
AU Daly, C.
DT 1984
TI Snow distribution patterns in the alpine krummholz zone
SO Progress in Physical Geogeography, 8:157-175
DE Hydrology
; University of Colorado
; Niwot Ridge
; Snow
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0205
AU Dansereau, P.
DT 1963
TI The barefoot scientist
SO Colorado Quarterly, 12(2):101-115
DE Ecology
; History
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
AB None
$
CL 1250
AU Davies, E.F.
DT 1994
TI Disturbance in alpine tundra ecosystems: The effects of digging by northern
 pocket (Thomomys talpoides)
SO M.S. thesis, Utah State University, Logan. 69 pp.
DE NWTLTER
; Niwot Ridge
; pocket gopher
; disturbance
; Thomomys talpoides
AB None
$
CL 1251
AU Davinroy, T.C.
DT 1994
TI Rates and controls of rock movement through alpine couloirs, Colorado Front
 Range
SO M.S. thesis, University of Colorado, Boulder. 161 pp.
DE NWTLTER
; geomorphology
; precipitation
; temperature
; ablation
; alpine
; Green Lakes Valley
; talus
AB None

2000

$
CL 0209
AU Davis, L.I.
; Hamilton, E.J.
; Niki, H.
; Wang, C.C.
; Weinstock, B.
; Bollinger, M.J.
; Fehsenfeld, F.C.
; Liu, S.C.
DT 1982
TI Fluorescence measurements of OH at Niwot Ridge
SO Proceedings of Second Symposium on the Composition of the Nonurban
 Troposphere. Williamsburg, Virginia, May 25-28, 1982. Boston: American
 Meteorological Society
DE Atmospheric sciences
; C-1 Climate Station
; Atmospheric Chemistry
; Wind
AB None
$
CL 0211
AU Davis, P.T.
; Waterman, S.E.
DT 1979
TI New radiocarbon ages for type Triple Lakes moraines, Arapaho Cirque,
 Colorado Front Range
SO Geological Society of America, Abstracts with Programs, 11(6):270. Abstract
DE Abstract
; Geomorphology
; Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Periglacial
; Dating - Radiocarbon and Other
; Glacier
AB None
$
CL 0210
AU Davis, P.T.
; Upson, S.
; Waterrman, S.E.
DT 1979
TI Lacustrine sediment variation  as an indicator of late Holocene climatic
 fluctuation, Arapahoe Cirque, Colorado Front Range
SO Geological Society of America, Abstracts with Programs, 11:410. Abstract
DE Abstract
; Climatology
; Glaciology
; Sedimentology
; Stratigraphy
; Chronology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Lake
; Sediment
; Climate - Discussion of
AB None
$
CL 0209a
AU Davis, P.T.
DT 1987
TI Late Pleistocene age for type Triple Lakes moraines, Arapaho Cirque,
 Colorado Front Range
SO Geological Society of America, Abstracts with Programs, 19(5)270.
DE abstract
; paleoecology
; Long-Term Ecological Research Program
; Boulder City Watershed
; glacier
; lake
; sediment
AB None
$
CL 0212
AU Davis, T.
; Burns, S.
; Caine, N.
DT 1984
TI Holocene deposits in Arapaho Cirque, Front Range
SO Guidebook for Field Trip 4, Eighth Biennial Meeting, American Quaternary
 Association. Boulder, Colorado, August 1984.  16 pp.
DE Guide
; Chronology
; Glaciology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Sediment
; Glacier
AB None
$
CL 0213
AU Davis, W.M.
DT 1911
TI The Colorado Front Range
SO Annals Association of American Geographers, 1:21-83
DE Geology
; History
AB None
$
CL 1438
AU Dearing, D.
DT 2001
TI Plant-herbivore interactions
SO Chapter 14 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 1331
AU Dearing, M.D.
DT 1997
TI The manipulation of plant toxins by a food-hoarding herbivore,
 Ochotona princeps.
SO Ecology 78: 774-781
DE NWTLTER
; bacterial inhibition
; decomposition
; Ochotona princeps
; phenolics
; pikas
; plant-herbivore interations
; toxin manipulation
AB Generalist mammalian herbivores typically avoid plant species containing high levels of plant
 secondary compounds because generalists are thought to lack the ability to process large quantities
 of these chemicals. Here I propose and test two hypotheses: (1) that food-hoarding herbivores
 behaviorally overcome consumption limits imposed by secondary compounds by storing food until the
 toxins degrade; and (2) that the presence of secondary compounds in cached plant material facilitates 
 the preservation of these items, as well as other cached items that lack such compounds. To evaluate
 these hypotheses, I conducted a number of field and laboratory experiments using the North American
 pika, Ochotona princeps, a generalist herbivore that consumes low-phenolic vegetation for subsequent
 consumption during winter.
$
CL 0214
AU Dene, H.
; Goodman, M.
; McKenna, M.C.
; Romero-Herrera, A.E.
DT 1982
TI Ochotona princeps (pika) myoglobin: An appraisal of lagomorph phylogeny
SO Proceedings Natural Academy of Science, U.S.A., 79:1917-1920
DE Biology
; Taxonomy & systematics
; Genetics
; Mountain Research Station - Affiliation
; Niwot Ridge
; Lagomorphs
; Biochemical
; Physiological
; Blood
AB None
$
CL 0215
AU Denton, G.H.
DT 1975
TI Glaciers of the American Rocky Mountains
SO In: Field, W.O. (ed.), Mountain Glaciers of the Northern Hemisphere.
 Hanover, NH: Cold Regions Research and Engineering Laboratory, Volume 
 1:509-542
DE Glaciology
; Indian Peaks Region
; Glacier
; Overview
AB None
$
CL 0215a
AU Dexter, L.R.
DT 1986
TI Aspect and elevation effects on the structure of the seasonal snow cover in
 Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 228 pp
DE Dissertation
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; altitude
; snow
; seasonal
AB None
$
CL 0216
AU Diaz, H.F.
; Barry, R.G.
; Kiladis, G.
DT 1982
TI Climatic characteristics of Pike's Peak, Colorado (1874-1888) and
 comparisons with other Colorado stations
SO Mountain Research and Development, 2:359-371
DE Climatology
; Long-Term Ecological Research Program
; D-1 Climate Station
; Altitude
; Climate - Data Included
; Climate - Discussion of
; NWTLTER
AB None
$
CL 0217
AU Dieffenbach, W.J.
DT 1966
TI Taxonomy of the cutthroat trout (Salmo clarki Richardson) of the South
 Platte drainage, Colorado
SO Copeia, 1966: 415-424
DE Taxonomy and systematics
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Mountain Research Station - Location
; Fish
; Stream
; Diversity
; Habitat
AB None
$
CL 1344
AU Diggle, P.K.
; Lower, S.S.
; Ranker. T.A.
DT 1998
TI Clonal diversity in alpine populations of Plygonum viviparum
SO International Journal of Plant Sciences 159:606-615
DE NWTLTER
; Plygonum viviparum
; diversity
AB Asexual reproduction is extremely common among arctic and alpine species, and successful sexual
 reproduction may be rare.  In asexual populations, the absence of segregation and recombination
 predicts reduced levels of genetic variation.  Thus, genetic diversity within arctic and alpine 
 plant populations may be quite low.  Allozyme analysis of three alpine populations of Polygonum 
 viviparum, a common herbaceous perennial with no observed sexual reproduction, revealed surprising 
 levels of genetic diversity.  There were 23 unique clones within a sample of 150 ramets.  Few clones 
 were large or distributed among all three sample populations: the majority of clones was rare (n was 
 less than or equal to 5) and unique to a single population.  Genotypic diversity differed among the 
 three sample populations.  The number of clones and measures of diversity and eveness were much lower 
 in the fell-field population than in wet meadow and dry meadow populations.  Overall, genotypic diversity 
 and structure of alpine P. viviparum are similar to other clonal species in which sexual reproduction 
 is rare, and they are similar to the average for clonal species in general.    
$
CL1477
AU Diggle, P.K.
; Meixner, M.A.
; Carroll, A.B.
; Aschwanden, C.F.
DT 2002
TI Barriers to sexual reproduction in Polygonum viviparum: a comparative developmental analysis of P. viviparum and P. bistortoides
SO Annals of Botany 89:145-156
DE None
AB None
$
CL 1317
AU Diggle, P.K.
DT 1997
TI Extreme preformation in alpine Polygonum viviparum: An architectural 
 and developmental analysis.
SO American Journal of Botany. 84:154-169.
DE NWTLTER
; preformation
; abortion
; allocation
; alpine
; architecture
; development
; Polygonum viviparum
; Polygonaceae
AB Preformation, the initiation of organs one or more years prior to
 maturation and function, is reported to be common and crucial for plant
 survival in arctic and alpine environments, yet the phenomenon is
 remarkably little studied.  In order to understand the role of preformation
 in the ecology and evolution of tundra species, this investigation takes a
 developmental and architectural approach to the analysis of plant growth
 and reproduction in the alpine perennial Polygonum viviparum L.  Analyses
 show that the extent and duration of preformation in P. viviparum is
 extraordinary.  Four years are required for each leaf and inflorescence to
 progress from initiation to functional and structural maturity
2000
.  This
 single salient feature of development has profound consequences for basic
 architecture, dynamics of resource allocation, and the timing of plant
 responses to environmental variation.  As a consequence of the protracted
 duration of leaf and inflorescence development, five cohorts of primordia,
 initiated in successive years, are borne simultaneously by an individual
 plant.  In the year prior to maturation leaves reach 30% of their maximum
 size, and the maximum potential reproductive output of each inflorescence
 is determined.  Thus, developmental processes that affect final morphology
 and resource allocation occur at least one year before functional maturity.
  From the developmental and architectural models constructed for P.
 viviparum, a one year delay in measurable plant responses to environmental
 variation is predicted.  The models also apply generally to arctic and
 alpine species and provide a mechanistic explanation for observed patterns
 of productivity at the community and ecosystem scale.
$
CL 0218
AU Dixon, H.N.
DT 1969
TI The growth of lodgepole pine in the Colorado Front Range as related to
 environment
SO Ph.D. dissertation, University of Colorado, Boulder. 108 pp.
DE Dissertation
; Climatology
; Institute of Arctic and Alpine Research
; C-1 Climate Station
; Boulder Watershed and Rainbow Lakes
; Conifers
; Altitude
; Climate - Discussion of
; Growth (Development)
; Tree
AB None
$
CL 0219
AU Dixon, J.C.
DT 1983
TI Chemical weathering of Late Quaternary cirque deposits in the Colorado Front
 Range
SO Ph.D. dissertation, University of Colorado, Boulder. 174 pp.
DE Dissertation
; Geomorphology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Altitude
; Precipitation
; Periglacial
; Climate - Discussion of
; Dating - Radiocarbon and Other
AB None
$
CL 0219a
AU Dixon, J.C.
DT 1986
TI Solute Movement on Hillslopes in the Alpine Environment of the Colorado
 Front Range
SO In: Abrahams, A.D. (ed.), Hillslope Processes. Boston: Allen and Unwin,
 139-159
DE Sedimentology
; Soil Sciences
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Chemistry
; Glacier
; Sediment
; Soils
; Stream
; Watershed
AB None
$
CL 0223
AU Douglass, M.M.
DT 1954
TI Subalpine fir succession on a ridge in Boulder County, Colorado
SO Journal Colorado-Wyoming Academy of Science, 4(6):45-46. Abstract
DE Abstract
; Ecology
; Institute of Arctic and Alpine Research
; C-1 Climate Station
; Climate - Discussion of
; Community
; Succession
; Conifers
AB None
$
CL 0222
AU Douglass, M.M.
DT 1954
TI Ecology of forest succession on a ridge in the subalpine forest of northern
 Colorado
SO M.A. thesis, University of Colorado, Boulder. 134 pp.
DE Thesis
; Ecology
; Institute of Arctic and Alpine Research
; C-1 Climate Station
; Altitude
; Climate - Discussion of
; Community
; Succession
; Conifers
AB None
$
CL 1307
AU Duguay, C.R.
; Walker, D.A.
DT 1996
TI Environmental modeling and monitoring with GIS: Niwot Long-Term Ecoligical
 Research site
SO Pp. 219-223. In Goodchild, M.F., L.T. Steyaert, B.O. Parks, C.A. 
 Johnston, D.R. Maidment, M. Crane, and S. Glendinning (eds.). GIS 
 and Environmental Modeling: Progress and Research Issues. Ft. Collins, 
 CO, GIS World, Inc.
DE NWTLTER
; modeling
; GIS
; geographic information systems
AB Research at the Niwot Ridge Long-term Ecological Research (LTER) site is
 concentrating on the ecological effects of altered snowpack and changes
 in precipitation and temperature regimes on alpine plant and animal 
 communities. This is accomplished through the use of: (1) a hierarchic
 geographic information system (HGIS), (2) a snow-fence experiment to 
 examine altered patterns of snowpack, and (3) analysis of remotely sensed
 data. The HGIS database is helping us study the links between species
 patterns at the level of plots, landscape patterns of plant communities,
 and regional patterns seen on satellite images. In this chapter, an
 overview of ongoing research activities using the HGIS at the plot,
 landscape, and regional scale is given. Results obtained during recent
 satellite remote sensing investigations at the Niwot Ridge LTER are also
 highlighted. These studies consist of: (1) determining the patterns of
 greenness as a function of regional climate, (2) evaluating the potential
 of multiresolution remotely sensed data combined with ancillary topoclimatic
 data to map tundra vegetation, (3) monitoring and modeling the spatial
 distribution and temporal patterns of snow cover, and (4) modeling the
 radiation and energy balance in the alpine.
$
CL 1264
AU Duguay, C.R.
DT 1993
TI Modelling the radiation budget of alpine snowfields with remotely sensed 
 data: Model formulation and validation
SO Annals of Glaciology 17:288-294
DE NWTLTER
; alpine tundra
; shortwave radiation
; longwave radiation
; radiative transfer scheme
; albedo
; Landsat-5 Thematic Mapper
; modelling
; Niwot Ridge
AB A model for estimating the radiation balance of alpine snowfields is
 presented. Shortwave and longwave downward flux densities are computed
 for sloping surfaces using a modified version of the two-stream 
 radiative transfer scheme  of Zdunkowski and others (1982). Surface
 albedo and thermal exitance values are estimated using Landsat-5 
 Thematic Mapper (TM) imagery and digital terrain data. The LOWTRAN7
 radiative transfer code is utilized in order to remove atmospheric
 effects in satellite imagery as well as calculating solar irradiance
 within TM spectral bands, for the determination of near-nadir 
 reflectance of snow. Under a Lambertian assumption, near-nadir
 reflectance measurements obtained from a few TM bands are used to
 calculate the total hemispherical reflectance (albedo) of snow. The 
 net all-wave radiation of snowfields is then simulated for the 
 complete day on the same date as that of the Landsat overflight. The
 model is tested using Landsat TM data acquired in late June 1984, and
 results compared with field measurements acquired on Niwot Ridge, 
 Colorado, U.S.A. Preliminary results are very encouraging but problems
 remain in the estimation of surface albedo from near-nadir satellite
 reflectance measurements of TM. These problems are discussed and 
 recommendations for future model improvements are given.
$
CL 1258
AU Duguay, C.R.
DT 1994
TI Remote sensing of the radiation balance during the growing
 season at the Niwot Ridge Long-Term Ecological Research site,
 Front Range, Colorado, U.S.A.
SO Arctic and Alpine Research 26:393-402
DE NWTLTER
; Niwot Ridge
; Saddle
; remote sensing
; radiation balance
; energy
; modeling
; albedo
; snowpack
; Landsat Thematic Mapper
; aspect
AB This paper examines the use of Landsat Thematic Mapper and digital
 terrain data combined with a radiative transfer model to map the 
 spatial patterns of the radiation balance at the Niwot Ridge Long-
 Term Ecological Research (LTER) site during the 1986 growing season.
 The analysis of maps and profiles of the components of the radiation
 balance for this alpine tundra site show particularly important
 contrasts in solar radiation receipts and longwave exitance between
 north- and south-facing slopes on a given day at the time of the 
 satellite overflights. However, the presence of snow and consequently
 higher albedo in the early part of the growing season is the most
 important factor that explains the difference in radiation balances
 between June and August. Leeward (east-facing) slopes that accumulate
 a deep snowpack during the winter experience the largest decrease in
 surface albedo. Albedo for these slopes decreased from about 0.55 to
 0.15 while remaining nearly the same for west-facing (windward)
 slopes. Finally, the good agreement between estimates of the 
 radiation balance and its components, and surface measurements
 acquired during three summer field seasons on Niwot Ridge suggest
 that the approach is suitable for mapping incoming and outgoing 
 fluxes over mountainous areas 
2000
at the spatial resolution of Landsat
 TM, and potentially at that of higher or lower resolution satellite
 sensors.
$
CL 1426
AU Duguay, C.R.
; LeDrew, E.F.
DT 1992
TI Estimating Surface Reflectance and Albedo from Landsat-5 Thematic Mapper over Rugged Terrain 
SO Photogrammetric Engineering & Remote Sensing. 58: 551-558
DE None
AB A model for estimating surface reflectance and albedo from satellite radiance measurements over rugged terrain is presented. Using a two-stream radiative transfer model, direct and diffuse sky irradiance as well as path radiance and atmospheric transmission are calculated for a horizontally homogenous atmosphere. A digital elevation model is use to estimate these parameters for surface of varying elevation, slope, and aspect.  The satellite- derived, corrected reflectance measurements obtained from Landsat Thematic Mapper Bands 2, 4, and 7 are integrated into a measure of albedo by the use of a weighted average scheme which takes into account the spectral reflectivity of the surface of interest as well as the spectral distribution of total shortwave irradiance.  The model is then tested over an area in the east slope of Colorado Front Range. Estimated values of albedo for selected surfaces in the alpine tundra are in substantial agreement with published data fro comparable surfaces and field measurements in the region.
$
CL 1520
AU Duguay, C.R. 
DT 1995
TI An approach to the estimation of surface net radiation in mountain areas using remotely sensed and digital terrain data
SO Theoretical and Applied Climatology.  v. 52 no. 1-2 pp. 55-68
DE NWTLTER
; LANDSAT THEMATIC MAPPER
; ALPINE TUNDRA
; FRONT RANGE
; ALBEDO
; COLORADO
; TEMPERATURE
; SATELLITE
; SEASON
; USA
AB An approach is proposed to estimate the net radiation load at the surface in mountain areas. The components of the radiation balance are derived using a radiative transfer :model combined with remotely sensed and digital terrain data. Integrated shortwave (0.28-6.00 mu m) and longwave irradiances (3.00-100.00 mu m) are computed using a modified version of the Practical Improved Flux Method (PIFM) of Zdunkowski et al. (1982) which makes use of digital topographic data in order to account for slope, aspect, and shading effects. Surface albedo and thermal exitance estimates are obtained using Landsat Thematic Mapper (TM) and digital terrain data combined with the LOWTRAN 7 atmospheric model (Kneizys et al., 1988). LOWTRAN 7 is utilized together with a set of terrain modeling programs to compute direct and diffuse sky irradiance for selected TM bands, and to remove atmospheric effects within the visible, near-infrared, mid-infrared, and thermal infrared bands of Landsat TM. Model testing in the Colorado alpine show a generally good correspondence between estimated values and field measurements obtained over comparable tundra surfaces during several field campaigns. The method is finally used to produce 1) maps of the components of the radiation balance at the time of Landsat TM overnight and 2) maps of daily totals of shortwave irradiance and net shortwave radiation on a typical summer day in the Colorado Rocky Mountains (i.e. including cloud cover effects). The results indicate that the proposed approach is particularly suitable for obtaining estimates of net radiation at the surface from the toposcale to the regional scale.$
CL 0226
AU Dyson, J.L.
DT 1937
TI Snowslide striations
SO Journal of Geology, 45:549-557
DE Hydrology
; Boulder Watershed and Rainbow Lakes
; Hazards
; Snow
; Avalanche
AB None
$
CL 0227
AU Dyson, J.L.
DT 1938
TI Snowslide erosion
SO Science, 87:365-366
DE Hydrology
; Boulder Watershed and Rainbow Lakes
; Hazards
; Snow
; Avalanche
AB None
$
CL 0228
AU Dyson, J.L.
DT 1952
TI Glaciers of the American Rocky Mountains
SO Triennial Report, Subcommittee on Glaciers, Section of Hydrology, AGU,
 American Geographic Society, New York, 37 pp.
DE Glaciology
; Indian Peaks Region
; Glacier
AB None
$
CL 1485
AU Ebersole, J.J.
DT 2002 
TI Recovery of alpine vegetation on small, denuded plots, Niwot Ridge, Colorado, U.S.A
SO Arctic, Antarctic, and Alpine Research. v. 34 no. 4 pp. 389-397
DE NWTLTER
; SEEDLING ESTABLISHMENT
; DISTURBANCE TYPE
; SOIL-MOISTURE
; LONG-TERM
; TUNDRA
; COMMUNITY
; DYNAMICS
; RESTORATION
; SWITZERLAND
; ECOSYSTEMS
AB Small plots (0.25 to 1.0 m(2)) denuded 13 and 31 yr previously were studied to investigate vegetation recovery at the alpine site of the Long-Term Ecological Research network. Recovery was slow, probably due to poor seedling survival. Covers of vascular plants and lichens were much lower on denuded plots than on controls except in late-melting snowbanks where natural disturbance by pocket gophers may have selected for disturbance-adapted species. Moister communities generally regained cover faster than drier communities. Vegetative expansion from plot edges provided most cover, although some colonizers originated from seed. Kobresia myosuroides, previously unknown to reproduce sexually in the Southern Rocky Mountains, occasionally colonized by seed. Essentially all vascular species acted as both colonizers and components of mature vegetation, and the vast majority of species are present in similar relative frequencies in control and disturbed plots. Previously studied alpine sites show either a similar lack of differentiation of early- and late-successional species or higher relative abundance of grasses in disturbed sites. In contrast to vegetation recovery in most temperate ecosystems, in these small plots on Niwot Ridge sequential replacement of species after disturbance does not occur.
$
CL 0229
AU Ebert, D.C.
DT 1972
TI Primary productivity as a function of vegetation composition in an alpine
 tundra environment
SO Journal Colorado-Wyoming Academy of Science, 7(2):27-28. Abstract
DE Abstract
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Community
; Productivity
AB None
$
CL 0232
AU Edmondson, C.H.
DT 1912
TI Protozoa of high mountain lakes in Colorado
SO University of Colorado Studies, 9:65-74
DE History
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Mount Evans and Guanella Pass Region
; James Peak
; Taxonomy & systematics
; Lake
; Invertebrates
AB None
$
CL 0233
AU Edwards, S.
DT 1972
TI Soil invertebrates in North American arctic and alpine tundra
SO In: Bowen, S. (ed.), Proceedings 1972 Tundra Biome Symposium, Lake
 Wilderness Center, University of Washington, 3-5 April, 1972, U.S. IBP Tundra
 Biome, 139-143
DE Biology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Insects
; Soil
; Distribution
; Taxonomy & systematics
AB None
$
CL 0238
AU Egeberg, R., Jr.
DT 1963
TI Inherent variations in the response of aspen to frost damage
SO Ecology, 44:153-156
DE Ecology
; Genetics
; Conifers
; Frost
; Morphological
; Physiological
; Tree
; Mountain Research Station - Location
; Mountain Research Station - Affiliation
AB None
$
CL 0239
AU Ehleringer, J.R.
DT 1973
TI Water relations in alpine tundra, Niwot Ridge, Colorado
SO M.S. thesis, California State University, San Diego. 111 pp.
DE Thesis
; Ecology
; Mountain Research Station - Affiliation
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Precipitation
; Snow
; Climate - Data Included
; Water
; Climate - Discussion of
; Bioenergetics
; Physiological
; Evapotranspiration
AB None
$
CL 0241
AU Ehleringer, J.R.
; Miller, P.C.
DT 1975
TI Water relations of selected plant species in the alpine tundra, Colorado
SO Ecology, 56:370-380
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Precipitation
; Snow
; Water
; Climate - Discussion of
; Bioenergetics
; Physiological
; Evapotranspiration
; U.S. International Biological Programme
AB None
$
CL 0240
AU Ehleringer, J.R.
; Miller, P.C.
DT 1975
TI A simulation model of plant water relations and production in the alpine
 tundra, Colorado
SO Oecologia, 19:177-
2000
193
DE Model
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Precipitation
; Snow
; Water
; Climate - Data Included
; Climate - Discussion of
; Bioenergetics
; Physiological
; Evapotranspiration
; Productivity
; U.S. International Biological Programme
AB None
$
CL 0244
AU Elgmork, K.
; Saether, O.R.
DT 1970
TI Distribution of invertebrates in a high mountain brook in the Colorado Rocky
 Mountains
SO University of Colorado Series in Biology, 31:3-58
DE Fauna
; Taxonomy & systematics
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Insects
; Lake
; Stream
; Distribution
; Plankton
; Invertebrates
AB None
$
CL 1328
AU Elias S.A.
DT 1995
TI Packrat middens, archives of desert biotic history
SO Encyclopedia of Environmental Biology 3:19-35
DE NWTLTER
; packrat
; woodrat
; middens
; paleoecology
AB Packrat middens are caches of objects, including edible plants, cactus spines,
 insect and vertebrate remains, small pebbles, and feces, brought to the den site
 for a variety of reasons, including food, curiosity, and den protection; then they
 are cemented into black tarry masses by packrat urine. Once dried, the exterior of
 the midden hardens into a protective coating that can preserve a paleoecological
 record for thousands of years in dry rock shelters of the arid West. The study of
 fossil records derived from middens is expanding our knowledge of the paleoecology 
 of this region by providing factual data on the nautre and timing of biotic 
 responses to environmental changes. Midden data are being used to test biogeographic,
 ecological, paleoclimatic, archaeological, and evolutionary hypotheses.
$
CL 0244a
AU Elias, S.
DT 1991
TI Insects and climate change: fossil evidence from the Rocky Mountains
SO BioScience 41(8):552-559
DE article
; Paleoecology
; Long-Term Ecological Research Program
; Rocky Mountain National Park
; Indian Peaks Region
; Insects
; climate - discussion of
; radiocarbon dating
; temperature
; glacier
; community
; distribution
; diversity
; forest-tundra ecotone
; pollen
; succession
; NWTLTER
AB None
$
CL 1318
AU Elias, S.A.
DT 1997
TI Ice Age History of Southwestern National Parks.
SO Smithsonian Institution Press. 200 pp.
DE NWTLTER
; paleoecology
; ice-age
; Canyonlands
; Grand Canyon
; Mesa Verde
; Chaco Canyon
; Big Bend
AB During the last ice age, the American Southwest was transformed from an
 arid landscape dominated by deserts to a very different landscape
 dominated by woodlands and forests.  Recreating the vegetation, animal
 life, and archaeology of this region during the last 100,000 years,
 this guidebook describes the little-known ecological history of the
 Southwest, focusing on five national parks and monuments: Canyonlands,
 Grand Canyon, Mesa Verde, Chaco Canyon, and Big Bend. Scott Elias
 describes the climatic forces that changed the face of the Southwest
 during the last glaciation. Shifts in atmospheric circulation brought
 moisture to now-arid regions throughout the Southwest. A menagerie of
 large Pleistocene animals roamed these regions, leaving behind
 fascinating clues about their lives in a surprisingly abundant fossil
 record preserved in dry caves. Packrat middens preserve the record of
 Southwestern vegetation and insect life through the last 40,000 years.
 Most of the large mammals became extinct, just after human hunters
 appeared in the Southwest, about 11,000 years ago. Elias explores the
 mystery of this massive extinction event, and its possible causes.
 Along with its companion books on the ice-age history of national parks
 in Alaska and the Rocky Mountains, this book explains the kind of
 evidence used to reconstruct past environments and ecosystems,
 including evidence gathered from geology, paleontology, and
 archaeology. Elias introduces paleoecology - the interactions among
 ancient plants, animals, and environments - to hikers, tourists, and
 armchair travelers.
$
CL 1245
AU Elias, S.A.
DT 1994
TI Quaternary insects and their environments
SO Washington, D.C.: Smithsonian Institution Press. 284 pp.
DE NWTLTER
; insects
; fossils
; Quaternary
; paleoenvironments
; climate change
AB None
$
CL 0245
AU Elias, S.A.
DT 1983
TI Paleoenvironmental interpretations of Holocene insect fossil assemblages
 from the La Poudre Pass site, northern Colorado Front Range
SO Palaeogeography, Palaeoclimatology, Palaeoecology, 41:87-102
DE Climatology
; Paleoecology
; Chronology
; Long-Term Ecological Research Program
; Insects
; Climate - Discussion of
; Distribution
; NWTLTER
AB None
$
CL 1290
AU Elias, S.A.
DT 1996
TI The ice-age history of National Parks in the Rocky Mountains
SO Washington, D.C.: Smithsonian Institution Press. 150 pp.
DE NWTLTER
; fossils
; paleoecology
; paleoclimate
; Rocky Mountains
; ice-age
; glaciers
AB During the last ice age, glaciers formed high in the Rocky Mountains
 and carved out the peaks and valleys visible today. Recreating the
 landscape and life forms of this era of the last great glaciations (from
 10,000 to 125,000 years ago), this guidebook describes a little-known
 yet pivotal period in the ecological history of four western national
 parks: Glacier, Yellowstone, Grand Teton, and Rocky Mountain. Scott A.
 Elias describes how great sheets of ice spread over and changed the
 shape of the land, forming the steep-walled valleys and braided rivers
 of Glacier National Park, the chain of so-called "pater noster" lakes in
 the lower Rockies, and the end moraines that dammed Jenny, Bradley,
 Taggart, and Phelps lakes in the Grand Teton park. Drawing on fossil
 evidence, he also introduces the large animals that thrived 21,000 years
 ago: dire wolves, short-faced bears, American cheetahs, and mammoths;
 these animals and others abruptly died off at the end of the last
 glaciation. He recounts the coming of humans to the region, and
 ascendance of the ecosystems we see today, and the lasting features
 (plant, animal, and topographical) of the last ice age. This
 guidebook along with its companion on the ice-age history of Alaskan
 national parks, relates as well the kinds of evidence and methods
 scientists use to reconstruct past environments. Covering geology,
 climate, ancient plant and animal life, and human presence, Elias
 introduces paleoecology - the interactions among plants, animals, and
 the prehistoric ecosystems - to hikers, tourists, and armchair
 travelers.
$
CL 0248a
AU Elias, S.A.
; Pollak, O.
TI Photographic atlas and key to windblown seeds of alpine plants from Niwot
 Ridge, Front Range, Colorado, USA
DT 1987
SO University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper 45.  28 pp
DE Technique
; Ecology
; Niwot Ridge
; Plants
; Wind
; Taxonomy
; NWTLTER
AB None
$
CL 0246
AU Elias, S.A.
DT 1984
TI Holocene paleoecology of Lake Isabelle, Colorado Front Range, based on
 insect fossils
SO Bulletin of Ecological Society of America, 65(2):168. Abstract
DE Thesis
; Paleoecology
; Chronology
; Long-Term Ecological Research Program
; Indian Peaks Region
; Insects
; Climate - Discussion of
; Distribution
AB None
$
CL 1285
AU Elias, S.A.
DT 1995
TI The ice-age history of Alaskan National Parks
SO Washington, D.C.: Smithsonian Institution Press. 150 pp.
DE NWTLTER
; fossils
; paleoecology
; Quaternary 
; paleoclimate
; Denali
; Kenai Fjords
; Glacier Bay
; Bering Land Bridge
AB Focusing on more than 30,000 years of Alaskan prehistory, The Ice 
 Age History of Alaskan National Parks vividly describes the geology, 
 climate, ancient plant and animal life, and human presence in four of 
 Alaska's national parks and preserves: Denali, Kenai Fjords, Glacier Bay, 
 and Bering Land Bridge. Scott A. Elias uncovers a time when glaciers shaped 
 the landscape, gouging out valleys, carving cirques and peaks, and leaving 
 moraines that blocked rivers and formed lakes. Using fossils as "witnesses" 
 of past environments, he recreates the bogs and steppe tund
2000
ra where caribou, 
 moose, large horned bison, and mammoths reigned 35,000 years ago. This 
 guidebook presents a unique perspective for the modern traveler. Geared 
 toward the general reader, it is the first in a series that will also survey 
 the prehistory of the Rocky Mountain and Southwest national parks. 
$
CL 0247
AU Elias, S.A.
DT 1984
TI Holocene tree limit positions and paleoenvironments of the Colorado Front
 Range, based on insect fossil assemblages from five high altitude sites
SO American Quaternary Association Eighth Biennial Meeting, Program and
 Abstracts, University of Colorado, Boulder, 36 Abstract
DE Thesis
; Paleoecology
; Chronology
; Long-Term Ecological Research Program
; Insects
; Climatology
; Climate - Discussion of
; Distribution
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0248b
AU Elias, S.A.
; Short, S.K.
; Clark, P.U.
TI Paleoenvironmental interpretations of the Late Holocene, Rocky Mountain
 National Park, Colorado, U.S.A.
DT 1986
SO Revue de Paleobiologie 5:127-142
DE Paleoecology
; Long-Term Ecological Research Program
; Rocky Mountain National Park - Location
; Insects
; Dating - Radiocarbon and Other
; Distribution
; Habitat
; Forest Tundra Ecotone (Timberline)
; Climate - Discussion of
; Pollen
; NWTLTER
AB None
$
CL 0248aa
AU Elias, S.A.
; Halfpenny, J.C.
DT 1991
TI Fox scat evidence of heavy predation on beetles on the alpine tundra, Front
 Range, Colorado
SO The Coleopterists Bulletin 45(2):189-190
DE article
; biology
; Long-Term Ecological Research Program
; Saddle
; insects
; carnivore
; bioenergetics
; food habits
; predation
; NWTLTER
AB None
$
CL 0248
AU Elias, S.A.
DT 1985
TI Paleoenvironmental interpretation of Holocene insect fossil assemblages from
 four high altitude sites in the Front Range, Colorado
SO U.S.A. Arctic and Alpine Research, 17:31-48
DE Paleoecology
; Chronology
; Long-Term Ecological Research Program
; Insects
; Climatology
; Climate - Discussion of
; Distribution
; NWTLTER
AB None
$
CL 1439
AU Elias, S.A.
DT 2001
TI Paleoecology and late quaternary environments of the Colorado Rockies
SO Chapter 15 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 1311
AU Elias, S.A.
DT 1996
TI Late pleistocene and holocene seasonal temperatures reconstructed from
 fossil beetle assemblages in the Rocky Mountains
SO Quaternary research 46:311-318
DE NWTLTER
; beetle assemblages
; paleoclimate
; Pleistocene
; Holocene
AB Mutual Climatic Range (MRC) analysis was applied to 20 fossil beetle
 assemblages from 11 sites dating from 14,500 to 400 yr B.P. The fossil 
 sites represent a transect of the Rocky Mountain region from northern 
 Montana to central Colorado. The analyses yielded estimates of mean July 
 and mean January temperatures. The oldest assemblage (14,500 yr B.P.) 
 yielded mean July values of 10-11 degrees C colder than present. 
 Postglacial summer warming was rapid, as indicated by an assemblage 
 dating 13,200 yr B.P., with mean July values only 3-4 degrees C cooler 
 than modern. By 10,000 yr B.P., several assemblages indicate 
 warmer-that-modern mean summer and winter values. By 9000 yr B.P. MCR 
 reconstructions indicate that both summer and winter temperatures were 
 already declining from an early Holocene peak. Mean July values remained 
 above modern levels and mean January values remained below modern levels 
 until 3000 yr B.P. A series of small-scale oscillations followed.
$
CL 0248ba
AU Elliott, P.F.
DT 1988
TI Foraging behavior of a central-place forager: field tests of theoretical
 predictions
SO American Naturalist, 131:159-174
DE article
; ecology
; Mountain Research Station
; C-1
; conifers
; rodents
; food habits
; competition
; tree
AB None
$
CL 0248c
AU Elliott, P.F.
DT 1988
TI The influence of population density and body size on the behavioral ecology
 of the pine squirrel (Tamiasciurus hudsonicus)
SO - Mountain Research Station, University of Colorado Natural History Paper 1,
 5 pp
DE Technical Report
; Ecology
; Mountain Research Station - Affiliation
; Rodents
; Population
; Growth (Development)
; Behavior
AB None
$
CL 0249
AU Ellsworth, P.M.
DT 1978
TI Ecology of zooplankton in high-altitude glacial moraine ponds
SO Ph.D. dissertation, University of Colorado, Boulder 221 pp.
DE Dissertation
; Ecology
; Geomorphology
; University of Colorado
; Niwot Ridge
; Invertebrates
; Altitude
; Lake
; Water
; Chemistry
; Distribution
; Diversity
; Trophic
; Plankton
AB None
$
CL 0251
AU Emerick, J.C.
; Webber, P.J.
DT 1982
TI The effects of augmented winter snow cover on the canopy structure of alpine
 vegetation
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37:63-72
DE Ecology
; U.S. International Biological Programme
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Snow
; Soil
; Temperature
; Climate - Data Included
; Community
; Morphological
; Productivity
; NWTLTER
AB None
$
CL 0250
AU Emerick, J.C.
DT 1976
TI Effects of artificially increased winter snow cover on plant canopy
 architecture and primary production in selected areas of Colorado alpine
 tundra
SO Ph.D. dissertation, University of Colorado, Boulder. 192 pp.
DE Dissertation
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Snow
; Soil
; Temperature
; Climate - Data Included
; Community
; Morphological
; Productivity
AB None
$
CL 0251a
AU Ennis, G.
; Sievering, H.
DT 1988
TI Seasonal comparison of soil-derived elemental air concentrations over the
 Niwot Ridge area
SO University of Colorado Long-Term Ecological Research Data Report 88/4. 12 pp
DE Data Report
; Atmospheric Sciences
; Long-Term Ecological Research Program
; Niwot Ridge
; Soils
; Wind
; Phenological (Seasonal)
AB None
$
CL 1514
AU Erickson, T.
; Williams, M.W.
; Tomaszewski, M.
DT 2001
TI Landscape controls on snow accumulation in an alpine catchments
SO Proceedings of the 69th Western Snow Conference, Sun Valley, Idaho, 2001
DE NWTLTER
AB None
$
CL 1420  
AU Erickson, T.A.
; Williams, M.W. 
; Sommerfeld, R.A. 
DT 2000
TI Spatial statistics of snowmelt
SO In: Bentley, L.R., J.F. Sykes, C.A. Gray and G.F. Pinder. Proceedings of the XIII International Conference on Computational Methods in Water Resources, Calgary, Canada, June 2000. A.A. Balkema publishers, Rottendam. 2: 1147-1152. Rottendam
DE None
AB None
$
CL 1571
AU Erickson, T.A.
; Williams, M.W.
; Winstral, A.
DT 2005
TI Persistence of topographic controls on the spatial distribution of snow in rugged mountain terrain, Colorado, United States
SO Water Resources Research vol. 41(4)
DE NWTLTER
AB We model the spatial distribution of snow depth across a wind-dominated alpine basin using a geostatistical approach with a complex variable mean. Snow depth surveys were conducted at maximum accumulation from 1997 through 2003 in the 2.3 km(2) Green Lakes Valley watershed in Colorado. We model snow depth as a random function that can be decomposed into a deterministic trend and a stochastic residual. Three snow depth trends were considered, differing in how they model the effect of terrain parameters on snow depth. The terrain parameters considered were elevation, slope, potential radiation, an index of wind sheltering, and an index of wind drifting. When nonlinear interactions between the terrain parameters were included and a multiyear data set was analyzed, all five terrain parameters were found to be statistically significant in predicting snow depth, yet only potential radiation and the index of wind sheltering were found to be statistically significant for all individual years. Of the five terrain parameters considered, the index of wind sheltering was found to have the greatest effect on predicted snow depth. The methodology presented in this p
2000
aper allows for the characterization of the spatial correlation of model residuals for a variable mean model, incorporates the spatial correlation into the optimization of the deterministic trend, and produces smooth estimate maps that may extrapolate above and below measured values. 
$
CL 1569
AU Ernest, S.K.M
DT 2005
TI Energy flow, body size, and community structure in small mammal communities
SO Ecology vol. 86 pp. 1407-1413
DE body size distribution
; body size-energy distribution
; community structure
; energetic equivalence
; macroecology
; small mammals
AB Body size has long been hypothesized to play a major role in community structure and dynamics. Two general hypotheses exist for how resources are distributed among body sizes: (1) resources are equally available and uniformly utilized across body sizes and (2) resources are differentially available to organisms of different body sizes, resulting in a nonuniform or modal distribution. It has also been predicted that the distribution of body sizes of species in a community should reflect the underlying availability of resources, with the emergence of aggregations of species around specific body sizes. I examined the relationship between energy utilization, body size, and community structure in nine small-mammal communities in North America. In all communities, energy use across body sizes was significantly different from uniform. In contrast, none of the nine species-level body size distributions were significantly different from uniform. Cross-site comparisons showed that, while the species-level body size distribution did not vary significantly among sites, the utilization of energy across body sizes did. These results suggest that uniform energy utilization does not occur in small-mammal communities and that the species-level body size distribution of a community is not determined by resource utilization.
$
CL 1406
AU Estey, T.B.
DT 1999
TI Krummholz vegetation and nutrient content are spatially distributed: 
   results from two alpine sites in Colorado
SO Senior Honor's Thesis. Department of Biological Sciences, University of 
   Denver. Denver, CO.
DE None 
AB None
$
CL 0254
AU Fahey, B.D.
DT 1973
TI An analysis of diurnal freeze-thaw and frost heave cycles in the Indian
 Peaks region of the Colorado Front Range
SO Arctic and Alpine Research, 5:269-281. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 151-163
DE Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Frost
; Soil
; Temperature
; Periglacial
; Climate - Data Included
; Water
; Climate - Discussion of
AB None
$
CL 0256
AU Fahey, B.D.
DT 1975
TI Nonsorted circle development in a Colorado alpine location
SO Geografiska Annaler, 57A:153-164
DE Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Frost
; Soil
; Temperature
; Periglacial
; Water
; Climate - Discussion of
AB None
$
CL 0253
AU Fahey, B.D.
DT 1971
TI A quantitative analysis of freeze-thaw cycles, frost-heave cycles and frost
 penetration in the Front Range of the Rocky Mountains, Boulder County,
 Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 305 pp.
DE Dissertation
; Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Frost
; Soil
; Temperature
; Periglacial
; Climate - Data Included
; Water
; Climate - Discussion of
AB None
$
CL 0255
AU Fahey, B.D.
DT 1974
TI Seasonal frost heave and frost penetration measurements in the Indian Peaks
 region of the Colorado Front Range
SO Arctic and Alpine Research, 6:63-70
DE Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Frost
; Soil
; Temperature
; Periglacial
; Climate - Data Included
; Water
; Climate - Discussion of
AB None
$
CL 0256a
AU Fahey, D.W.
; Hubler, G.
; Parrish, D.D.
; Williams, E.J.
; Norton, R.B.
; Ridley, B.A.
; Singh, H.B.
; Liu, S.C.
; Fehsenfeld, F.C.
DT 1986
TI Reactive nitrogen species in the troposphere: Measurements of NO, NO2, HNO3,
 particulate nitrate, peroxyacetl nitrate (PAN), O3, and total reactive odd
 nitrogen (NOy) at Niwot Ridge, Colorado
SO Journal of Geophysical Research 91:9781-9793
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
AB None
$
CL 0258
AU Fareed, M.
DT 1973
TI Canopy structure and phenology of alpine tundra vegetation
SO M.S. thesis, Utah State University, Logan. 43 pp.
DE Thesis
; Ecology
; Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Community
; Morphological
; Phenological (seasonal)
AB None
$
CL 0259
AU Fareed, M.
; Caldwell, M.M.
DT 1975
TI Phenological patterns of two alpine tundra plant populations, Niwot Ridge,
 Colorado
SO Northwest Science, 49:17-23
DE Ecology
; Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Phenological (seasonal)
AB None
$
CL 0261
AU Fehsenfeld, F.C.
; Goldan, P.D.
; Phillips, M.P.
; Sievers, R.E.
DT 1981
TI Selective electron capture sensitization
SO Chapter 4. In: Zlatkis, A. and Poole, C.F. (eds.), Electron Capture Theory
 and Practice in Chromatography. New York: Elsevier, 69-90
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; Atmospheric Chemistry
; C-1 Climate Station
AB None
$
CL 0260a
AU Fehsenfeld, F.C.
; Bollinger, M.J.
; Liu, S.C.
; Parrish, D.D.
; McFarland, M.
; Trainer, M.
; Kley, D.
; Murphy, P.C.
; Albritton, D.L.
; Lenschow, D.H.
DT 1983
TI A study of ozone in the Colorado mountains
SO Journal of Atmospheric Chemistry, 1:87-105
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; ozone
AB None
$
CL 1491
AU Fenn, M.E.
; Baron, J.S.
; Allen, E.B.
; Rueth, H.M.
; Nydick, K.R.
; Geiser, L.
; Bowman, W.D.
; Sickman, J.O.
; Meixner, T.
; Johnson, D.W.
; Neitlich, P.
DT 2003
TI Ecological Effects of Nitrogen Deposition in the Western United States
SO BioScience v. 53 pp. 404-420
DE NWTLTER
; nitrogen saturation
; streamwater nitrate
; eutrophication
; lichens
; biotic communities
AB In the western United States vast acreages of land are exposed to low levels of atmospheric nitrogen (N) deposition, with interspersed hotspots of elevated N deposition downwind of large, expanding metropolitan centers or large agricultural operations. Biological response studies in western North America demonstrate that some aquatic and terrestrial plant and microbial communities are significantly altered by N deposition. Greater plant productivity is counterbalanced by biotic community changes and deleterious effects on sensitive organisms (lichens and phytoplankton) that respond to low inputs of N (3 to 8 kilograms N per hectare per year). Streamwater nitrate concentrations are elevated in high-elevation catchments in Colorado and are unusually high in southern California and in some chaparral catchments in the southwestern Sierra Nevada. Chronic N deposition in the West is implicated in increased fire frequency in some areas and habitat alteration for threatened species. Between hotspots, N deposition is too low to cause noticeable effects or has not been studied.
$
CL 0262
AU Fenneman, N.N.
DT 1902
TI The Arapahoe Glacier in 1902
SO Journal of Geology, 10:839-851
DE Glaciology
; History
; Glacier
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 1341
AU Fisk, M.C
; Schmidt, S.K.
; Seastedt, T.R.
DT 1998
TI Topographic patterns of above- and belowground production and nitrogen cycling in alpine tundra
SO Ecology 79:2253-2266
DE NWTLTER
; alpine tundra
; microbial activity
; net primary production
; nitrogen cycling
; nitrogen transformations
; root production
; topographic gradient
AB Topography controls snowpack accumulation and hence growing-season length,
 soil water availability, and the distribution of plant communities in the
 Colorado Front Range alpine. Nutrient cycles in such an environment are 
 likely to be regulated by interactions between topographically determined
 climate and plant species composition. We investigated variation
2000
 in plant
 and soil components of internal N cycling across topographic gradients of 
 dry, moist, and wet alpine tundra meadows at Niwot Ridge, Colorado. We expected
 that plant production and N cycling would increase from dry to wet alpine
 tundra meadows, but we hypothesized that variation in N turnover would span
 a proportionately greater range than productivity, because of feedbacks between
 plants and soil microbial processes that determine N availability. Plant production
 of foliage and roots increased over topographic sequences from 280 grams per
 meter squared per year in dry meadows to 600 grams per meter squared per year
 in wet meadows and was significantly correlated to soil moisture. Contrary to
 our expectation, plant N uptake for production increased to a lesser degree,
 from 3.9 grams N per meter squared per year in dry meadows to 6.8 grams N
 per meter squared per year in wet meadows. In all communities, the belowground
 component accounted for the majority of biomass, production, and N use for
 production. Allocation belowground also differed among communities, accounting
 for 70% of total production and 80% of N use for production in dry meadows 
 compared to 55% of production and 65% of N use for production in moist meadows.
 Variation in microbial processes was highly related to soil moisture, and we
 found very consistent relationships among microbial respiration, gross N
 mineralization, and N immobilization among communities. These results indicate
 that the topographic soil moisture gradient is in fundamental control of
 the patterns of N turnover among communities and that differences in plant
 species do not appear to be as important.
$
CL 1304
AU Fisk, M.C.
; Schmidt, S.K.
DT 1996
TI Microbial response to nitrogen addition in alpine tundra soils.
SO Soil Biology and Biochemistry 28: 751-755
DE NWTLTER
; nitrogen
; microbes
; soil
AB Soil nitrogen transformations were measured the year following nitrogen 
 fertilization of alpine Kobresia myosuroides meadows to determine the influence
 of greater plant production and N content on net N mineralization and the
 microbial N pool. Previously fertilized soils contained substantially greater
 amounts of organic N than control soils. The average increase in soil organic
 N accounted for 75% of total added N and, although variable, this quantity
 suggests a large capacity for retention of added N in these soils. Nitrogen
 transformations and more active pools also responded to fertilization. Net
 N mineralization, nitrification and soil inorganic N concentrations clearly
 were higher in fertilized than in control plots through out the snow-free
 season. The most pronounced increase in mineralization in fertilized relative
 to control soils occurred during the second half of the snow-free period
 (mid-July-October), primarily after the short alpine growing season (June-mid-
 August). Although the soil microbial N pool was not affected by fertilization
 during the growing season, microbial N did increase in the fall in fertilized
 compared to control soils, coinciding with the time of greatest N mineralization.
 The late season net uptake of N into the microbial pool exceeded by several
 times present rates of anthropogenic N inputs to these soils, and the microbial
 biomass may act as an increasingly important short-term sink for available N
 if N deposition to these areas continues to increase.
$
CL 1286
AU Fisk, M.C.
; Schmidt, S.K.
DT 1995
TI Nitrogen mineralization and microbial biomass nitrogen dynamics in 
 three alpine communities
SO Soil Science Society of America Journal, 59:1036-1043
DE NWTLTER
; nitrogen
; nitrogen mineralization
; microbial biomass
; nitrification
; Niwot Ridge
; biogeochemistry
; nutrient cycles
AB The alpine tundra of the Colorado Front Range supports a variety
 of plant communities whose distribution corresponds to their topographic
 position. Our objectives were to: (i) determine patterns in net N 
 mineralization and microbial N pools among three communities, Kobresia,
 Acomastylis, and Carex meadows, that span a topographic gradient and 
 (ii) relate any patterns to soil microclimate differences among these
 communities. Average yearly net N mineralization rate, measured with
 an in situ core incubation technique, were 1.2 g N m^-2 in 1991 and 
 1.0 g N m^-2 in 1992. No differences were detected in yearly N 
 mineralization rates among the three communities; however, net 
 nitrification and other soil properties were found to differ among
 communities. Net N mineralization rates and microbial N showed strong
 temporal variation, and this variation was related to different 
 variables for each community. Seasonal variation in N mineralization
 was related to soil water and microbial N in Kobresia meadows, to
 soil temperature and microbial N in Acomastylis meadows, and to 
 soil water and temperature in Carex meadows. Seasonal changes in
 microbial N were related to soil water in Kobresia and Acomastylis 
 meadows. Large fluctuations in microbial N indicate that periodic
 losses from the microbial pool may be important to N availability
 in this alpine tundra site.
$
CL 1272
AU Fisk, M.C.
DT 1995
TI Nitrogen dynamics in an alpine landscape
SO Ph.D. dissertation, University of Colorado, Boulder. 114 pp.
DE NWTLTER
; microbial processes
; nitrogen cycling
; Niwot Ridge
; nitrogen mineralization
; nutrient cycling
; nitrogen immobilization
; microbial biomass
; biogeochemistry
AB The plant and soil components of the alpine nitrogen (N) cycle
 were investigated in three dominant plant communities on Niwot
 Ridge, a tundra site in the Colorado Front Range. The communities 
 generally occur across a landscape gradient, from dry and 
 windblown in the dry meadow to wet meadow sites that receive 
 snowmelt through much of the growing season. This assessment of 
 alpine N cycling had three basic goals: first, to quantify the N 
 pools and annual fluxes through the plant and soil fractions 
 across the toposequence of plant communities; second, to 
 investigate in more detail the microbial processes contributing 
 to N turnover, and finally, to determine the impacts of enhanced 
 N availability on these microbial processes. N pools in the major 
 plant (above- and belowground) and soil (detritus and soil 
 organic matter) fractions increased across the toposequence, from 
 lowest in dry meadows to the highest in wet meadows. Similarly, 
 annual N uptake by both the above- and belowground plant 
 components was lowest in dry meadows and highest in wet meadows. 
 Annual estimates of net N mineralization did not account for 
 plant N requirements, nor did they correspond to the topographic 
 pattern of plant N uptake. In contrast, laboratory incubations of 
 soil at several times throughout the snow-free season did exhibit 
 rates of total N release from organic matter (gross 
 mineralization) that were lowest in dry meadows and highest in 
 wet meadows, in agreement with the patterns of plant N uptake. 
 Results of soil incubations also revealed that microbial uptake 
 of N (immobilization) occurred at the same or greater rates than
 gross mineralization of N, indicating a very rapid or tight
 recycling of N through the microbial pools in all communities.
 The close relationships between gross N mineralization and
 immobilization suggests that substrate controls were not likely
 a factor in N turnover differences among communities, however
 the balance between gross N mineralization and immobilization
 was considerably altered by the additions of N to dry meadow
 soils. Lower growth efficiency of the microbial biomass in 
 fertilized compared to control soils was paralleled by a lower
 N requirement, hence acting as a positive feedback to N
 availability in fertilized soils.
$
CL 1419
AU Fisk, M.C.
; Brooks, P.D.
; Schmidt, S.K.
DT 2001
TI Nitrogen cycling in an alpine ecosystem
SO In: Alpine Dynamics: The structure and function of an alpine ecosystem. W. Bowman and T.R. Seastedt. (eds.) Oxford Un
2000
iversity Press
DE None
AB None
$
CL 0265
AU Fjellberg, A.
DT 1984
TI Collembola from the Colorado Front Range, U.S.A.
SO Arctic and Alpine Research, 16:193-208
DE Fauna
; Taxonomy & systematics
; Long-Term Ecological Research Program
; Altitude
; Distribution
; Insects
; NWTLTER
AB None
$
CL 0266
AU Flock, J.W.
DT 1976
TI The influence of snow cover and soil moisture on bryophyte and lichen
 distribution, Niwot Ridge, Boulder County, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 168 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Lichens
; Bryophytes
; Snow
; Soil
; Water
; Community
; Distribution
AB None
$
CL 0267
AU Flock, J.W.
DT 1978
TI Lichen-bryophyte distribution along a snow-cover soil-moisture gradient,
 Niwot Ridge, Colorado
SO Arctic and Alpine Research, 10:31-47. Abstract reprinted in: Ives, J.D.
 (ed.), 1980: Geoecology of the Colorado Front Range. Boulder: Westview Press,
 395.  Abstract
DE Abstract
; Ecology
; University of Colorado
; Niwot Ridge
; Lichens
; Bryophytes
; Snow
; Soil
; Water
; Community
; Distribution
AB None
$
CL 0268
AU Flock, J.W.
DT 1983
TI Changes in alpine plant communities
SO Journal Colorado-Wyoming Academy of Sciences, 15(1):37. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Community
; Diversity
AB None
$
CL 0269
AU Flock, J.W.
DT 1983
TI Changes in plant communities between 1972 and 1982 on Niwot Ridge
SO University of Colorado Long-Term Ecological Research Data Report, 83/6 38
 pp.
DE Data report
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Community
; Diversity
AB None
$
CL 0270
AU Flock, J.W.
DT 1985
TI Changes in plant communities between 1973 and 1983 on Niwot Ridge
SO University of Colorado Long-Term Ecological Research Data Report, 85/5. 67
 pp.
DE Data report
; Ecology
; Long Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Community
; Diversity
AB None
$
CL 1518
AU Forbis, T.A.
; Larmore, J.
; Addis, E. 
DT 2004
TI Temporal patterns in seedling establishment on pocket gopher disturbances
SO Oecologia v. 138 pp. 112-121
DE NWTLTER
; demography
; germination
; gopher mound
; seed bank
; survival analysis
AB Disturbances often facilitate seedling establishment, and can change the species composition of a community by increasing recruitment of disturbance-adapted species. To understand the effects of pocket gopher disturbances on alpine seedling dynamics, we examined the gopher disturbances' effects on seedling emergence and survival on gopher disturbances 0 to 5 years old. In contrast to results from most other ecosystems, these recently created gopher mounds had lower seedling emergence and survival rates than undisturbed areas. A lack of correlation between species' abundances on gopher mounds and undisturbed sites in one of the two communities studied suggested that a suite of disturbance-adapted species recruited onto the mounds. To explain low seedling emergence on recent gopher mounds, we quantified gopher mound seed banks and studied recruitment in a site with mounds that ranged from 0 to >20 years old. Seed numbers in first-year gopher mound soils were extremely low relative to undisturbed soils, and this pattern was mirrored in seedling establishment patterns over the long term. Gopher disturbance depressed seedling emergence density for the first 5 years. Subsequently, emergence density increased until at least 20 years following the disturbance. Emergence on disturbances more than 20 years old was higher than on undisturbed sites. Therefore, gopher disturbances probably facilitate seedling establishment in alpine dry and moist meadow; however, this process takes place over decades.
$
CL 1561
AU Forbis, T.A.
; Doak, D.F.
DT 2004
TI Seedling establishment and life history trade-offs in alpine plants
SO American Journal of Botany vol. 91 (7) pp. 1147-1153
DE NWTLTER
; demography
; elasticity
; life history
; longevity
; matrix model
; perennial
; seedling
; trade-off
; POPULATION-DYNAMICS
; DEMOGRAPHY
; HERB
; REPRODUCTION
; PATTERNS
; GROWTH
; CONSEQUENCES
; ELASTICITY
; VIABILITY 
AB Seedling establishment is central to population maintenance for nonclonal plant species. Plants with low recruitment rates are expected to have high survival rates, and life history theory indicates there should be a single curve for the trade-off between recruitment and mortality that applies to most or all plant species. Alpine perennials are thought to have extraordinarily low recruitment rates because of the harsh environment, but the importance of recruitment in the life history of these plants is unknown. Two alpine cushion plant species, Minuartia obtusiloba and Paronychia pulvinata, were used to (1) determine the role of recruitment in population maintenance and (2) determine whether the fecundity/mortality trade-off for these alpine plants falls on or off of the curve for other perennial plant species. Using size-based population projection matrices, we determined that the life history of Minuartia and Paronychia emphasizes recruitment less than that of any other nonclonal species in a literature survey. Estimated maximum life spans of these two species are 200 and 324 yr, respectively, and a regression with other perennial species from the literature indicated that the relationship between fecundity and mortality in these alpine species is consistent with the predicted trade-off curve for perennial species from other environments.
$
CL1456
AU Forbis, T.A.
; Diggle, P.K.
DT 2001
TI Subnivean enbryo development in the alpine herb Caltha leptosepala (Ranunculaceae)
SO Canadian Journal of Botany. v.79 pp 635-642
DE NWTLTER
AB None
$
CL 1496
AU Forbis, T.A.
DT 2003
TI Seedling Demography in an Alpine Ecosystem
SO American Journal of Botany v. 90(8) pp. 1197-1206
DE Colorado Rocky Mountains
; demography
; germination
; plant community
; recruitment
; survival analysis
; tundra
AB Seedling establishemt has long been believed to be rare on alpine tundra because of predicted life history trade-offs, the clonality of alpine species, and harshness of the alpine climate.  Contrary to the idea that seedlings are rare on alpine tundra, a 4-yr demographic study of seedlings at Niwot Ridge, Colorado, USA, found seedlings at high densities, particularly in wetter plant communities.  Higher germination densities were associated with higher soil moistures both across communities and across time.  Mortality of seedlings was highest in the first year and decreased in subsequent years.  Species' abundances differed between seedling and adult populations.  Many forbs that lacked vegetative reproduction were significantly more abundant amond seedling populations, and many monocots and clonal forbs were more abundant among adult populations.  In a comparison with published demographic rates, seedling recruitment and mortality rates  of Niwot Ridge species fell above or within rates for a wide range of perennial species.  Therefore, germination and seedling establishment stages are no more limiting to sexual reproduction in alpine plants than in other perennial plants.
$
CL 0272
AU Foreman, M.F.
DT 1971
TI Growth, flowering, and vivipary in arctic and alpine populations of
 Deschampsia caespitosa (L.) Beauv., Poa alpina L., and Trisetum spicatum (L.)
 Richt
SO Ph.D. dissertation, University of Colorado. 336 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Rollins Pass and Tolland
; Angiosperms
; Climate - Discussion of
; Phenological (seasonal)
; Germination (Dormancy)
; Growth (Development)
; Reproduction
AB None
$
CL 0273
AU Forsyth, J.K.
DT 1980
TI Principal components analysis of subalpine vegetation on the east slope of
 the Colorado Rocky Mountains
SO Ph.D. dissertation, University of Colorado, Boulder. 101 pp.
DE Dissertation
; Ecology
; University of Colorado
; Angiosperms
; Conifers
; Altitude
; Distribution
; Boulder Watershed and Rainbow Lakes

2000
; Climate - Data Included
AB None
$
CL 0274
AU Foss, F.
; Hinkelman, J.W., Jr.
DT 1984
TI Denver ARTCC evaluation of PROFS mesoscale weather products
SO A Joint Report of the Program for Regional Observing and Forecasting
 Services (325 Broadway, Boulder, Colorado 80303) and the Denver Air Route 
 Traffic Control Center (Longmont, Colorado 80501). 23 pp. plus appendices
DE Technique
; Climatology
; NOAA - Profs
; C-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0277
AU Foster, S.Q.
; Windell, J.T.
DT 1982
TI Ecological characteristics of an alpine-subalpine second order stream
SO Journal Colorado-Wyoming Academy of Sciences, 14(1):14. Abstract
DE Abstract
; Ecology
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Mountain Research Station - Location
; Altitude
; Stream
AB None
$
CL 0278
AU Foster, S.Q.
; Windell, J.T.
DT 1984
TI The intermediate-disturbance hypothesis and elevational trends in
 macroinvertebrate species diversity
SO Bulletin of Ecological Society of America, 65(2):131. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Mountain Research Station - Location
; Insects
; Altitude
; Stream
; Community
; Distribution
AB None
$
CL 0276
AU Foster, S.Q.
DT 1984
TI The intermediate-disturbance hypothesis and elevational trends in
 macroinvertebrate species diversity
SO Journal Colorado-Wyoming Academy of Sciences, 16(1):6. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Mountain Research Station - Location
; Insects
; Altitude
; Stream
; Community
; Distribution
AB None
$
CL 0275
AU Foster, S.Q.
DT 1984
TI Elevational trends in macroinvertebrate species diversity, biotic condition,
 and functional group condition in three Colorado Front Range streams
SO M.A. thesis, University of Colorado, Boulder. 110 pp.
DE Thesis
; Ecology
; Long-Term Ecological Research Program
; Mountain Research Station - Location
; Insects
; Altitude
; Stream
; Community
; Distribution
; Boulder Watershed and Rainbow Lakes
; NWTLTER
AB None
$
CL1452
AU Fourment, T.
; Emerling, D (illus).
DT 2002
TI My Water Comes from the Mountains
SO Roberts Rinehart Publishers,Rowman and Littlefield Publishing Group
DE Book, NWTLTER, children's book
AB None
$
CL 1405
AU Fox, A.M.
DT 1999
TI Equivalent permeability of continental, alpine snowpack
SO M.S. Thesis. University of Colorado, Boulder. 116 pp.
DE None
AB None
$
CL 0278a
AU Francoeur, A.
; Elias, S.A.
DT 1985
TI Dolichoderus taschenbergi Mayr (Hymenoptera: Formicidae) from an early
 Holocene fossil insect assemblage in the Colorado Front Range.
SO Psyche, 92(2-3):303-307
DE Paleoecology
; Taxonomy
; Long-Term Ecological Research Program
; Indian Peaks Region
; Insects
; Dating - Radiocarbon and Other
; Lake
; Distribution
; Forest Tundra Ecotone (Timberline)
; NWTLTER
AB None
$
CL 0278b
AU Frank,T.D.
; Isard, S.A.
DT 1986
TI Alpine vegetation classification using high resolution aerial imagery and
 topoclimatic index values
SO Photogrammetric Engineering and Remote Sensing, 52(3):381-388
DE Remote Sensing
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Climate - Discussion of
; Topography
; Community
; Physiographic
AB None
$
CL 1257
AU French, N.R.
DT 1990
TI The utility of models in the study of mountain development and
 transformation 
SO Mountain Research and Development 10: 141-149
DE NWTLTER
; modeling
AB None
$
CL 0280
AU French, N.R.
DT 1951
TI The effect of altitude on the migration of birds in the vicinity of Boulder,
 Colorado
SO M.A. thesis, University of Colorado, Boulder. 58 pp.
DE Thesis
; Ecology
; Long-Term Ecological Research Program
; Birds
; Altitude
; Movement
AB None
$
CL 0280b
AU French, N.R.
TI Hierarchical conceptual model of the alpine geosystem
DT 1986
SO Arctic and Alpine Research, 18(2):133-146
DE Journal
; Model
; Overview
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Plants
; Animals
; Climate - Discussion of
; Dating - Radiocarbon and Other
; Community
; Ecosystem
; Scale
; Hierarchy
; NWTLTER
AB None
$
CL 0280a
AU French, N.R.
DT 1985
TI Hierarchical conceptual model of the alpine geosystem
SO University of Colorado Long-Term Ecological Research Working Paper 85/1. 28
 pp
DE Data Report
; Model
; Overview
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Plants
; Animals
; Climate - Discussion of
; Dating - Radiocarbon and Other
; Community
; Ecosystem
; Scale
; Hierarchy
AB None
$
CL 1214
AU Fry, B.
DT 1991
TI Stable isotope diagrams of freshwater food webs
SO Ecology 72: 2293-2297
DE NWTLTER
; carbon isotopes
; nitrogen isotopes
; food webs
; organic matter
; Niwot Ridge
; litter
; soil
AB None
$
CL 0285aa
AU Funk, D.
; Bonde, E.K.
DT 1989
TI Fertilizing effects of artificial sulfuric-acid mists on Bistorta vivipara
 plants in alpine tundra
SO Arctic and Alpine Research, 21(2):169-174
DE article
; ecology
; Long-Term Ecological Research Program
; Saddle
; angiosperms
; acid deposition
; fertilizer
; growth
; nutrients
; NWTLTER
AB None
$
CL 0283a
AU Funk, D.W.
; Bonde, E.K.
DT 1989
TI Abortion of floral buds in Acomastylis rossii plants exposed to artificial
 acid mists in alpine tundra
SO American Journal of Botany 76:878-883
DE article
; biology
; Long-Term Ecological Research Program
; Saddle
; Angiosperms
; acid deposition
; disease
; germination
; nutrients
; NWTLTER
AB None
$
CL 0285
AU Funk, D.W.
; Bonde, E.K.
DT 1984
TI Effects of artificial acid mist on two species of alpine plants
SO New Mexico Journal of Science, 24(1):46. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Acid Deposition
; Precipitation
; Growth (Development)
; Reproduction
AB None
$
CL 0284
AU Funk, D.W.
; Bonde, E.K.
DT 1983
TI Effects of simulated precipitation on growth and reproduction of two alpine
 plant species, Acomastylis rossii and Bistorta vivipara
SO Journal Colorado-Wyoming Academy of Sciences, 15(1):37. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Acid Deposition
; Precipitation
; Growth (Development)
; Reproduction
AB None
$
CL 1200
AU Funk, D.W.
DT 1987
TI Differential sensitivity of two Colorado alpine plant species to artificial
 acid mists
SO Ph.D. dissertation, University of Colorado, Boulder. 179 pp.
DE NWTLTER
; acid deposition
; plant physiology
AB None
$
CL 0283
AU Funk, D.W.
DT 1983
TI Effects of simulated acid precipitation on growth and reproduction of two
 alpine plant species, Acomastylis rossii (R.Br.) E.Greene and Bistorta
 vivipara L., in the field
SO M.A. thesis. University of Colorado, Boulder. 80 pp.
DE Thesis
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Acid Deposition
; Precipitation
; Growth (Development)
; Reproduction
; NWTLTER
AB None
$
CL 0285a
AU Funk, D.W.
; Bonde, E.K.
DT 1986
TI Effects of artificial acid mist on growth and reproduction of two alpine
 plant species in the field
SO American Journal of Botany, 73(4):524-528
DE Ecology
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Angiosperms
; Acid Deposition
; Community
; Germination (Dormancy)
; Nitrogen
; Nutrients
; Phenology
; Pollution
; Reproduction
; NWTLTER
AB None
$
CL 0285c
AU Furbish, D.J.
DT 1988
TI A test of recent convolution-integral models describing the migration of
 river meanders
SO International Association of Hydraulic Research, Proceedings of the
 International Conference on Fluvial Hydraulics. Budapest, Hungary, 1988,
 298-303
DE Model
; Hydrology
; Geomorphology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Stream
; Water
; NWTLTER
AB None
$
CL 0285ab
AU Furbish, D.J.
DT 1987
TI Conditions for geometric
2000
 similarity of coarse stream-bed roughness
SO Mathematical Geology 19:291-307
DE article
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; stream
; NWTLTER
AB None
$
CL 0285b
AU Furbish, D.J.
DT 1988
TI River-bend curvature and migration: how are they related?
SO Geology, 16:752-755
DE Hydrology
; Geomorphology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Stream
; Water
; NWTLTER
AB None
$
CL 0285ca
AU Furbish, D.J.
DT 1988
TI Variation in pivot angles of coarse sediment particles: the influence on
 particle mobility in steep streams
SO Transactions, American Geophysical Union, 69(44):1218. Abstract
DE article
; geomorphology
; Long-Term Ecological Research Program
; Boulder City Watershed
; stream
; sediment
; stream
AB None
$
CL 1234
AU Furbish, D.J.
DT 1993
TI Flow structure in a bouldery mountain stream with complex bed topography
SO Water Resources Research 29: 2249-2263
DE NWTLTER
; geomorphology
; North Boulder Creek
; hydrology
AB Bouldery, mountain streams often possess highly irregular banks and beds
 composed of bedrock outcrops and immobile casts mingled with alluvial bed
 forms. This complex morphology can induce locally strong flow accelerations
 and distortions of the water surface. Despite the complexity of flow at a
 scale of one or two channel widths and smaller, it is possible to identify a
 filament of high streamwise velocity that exhibits a near-oscillatory
 structure, albeit noisy, as it threads back and forth across the channel over
 tens of channel widths; and transverse water surface slopes locally mimic
 transverse bed slopes. These features are responses to shoaling of flow over
 an irregular, nearly random, bed topography. To clarify the mechanisms leading
 to this structure, linearized forms of the depth-averaged equations of
 momentum and continuity are solved in the wavenumber domain, for the case of a
 straight channel with uniform width, using a doubly periodic description of
 bed topography as a forcing term. Systematic changes in the strength and phase
 of velocity and water surface responses with varying wavenumber of bed
 undulations reflect mutual interaction of streamwise and transverse flow
 accelerations and transverse water surface slopes. These results are cast in
 terms of spectral responses to a bed composed of many superimposed waveforms.
 Then the shapes of spectra describing transverse water surface slopes and the
 transverse coordinate of the high-velocity filament, as measured from 100
 equally spaced sections along North Boulder Creek, Colorado, are predicted by
 the analysis. The levels of the spectra are underestimated, however, due to
 factors not taken into account by linear analysis, notably variations in
 width, and form drag associated with coarse roughness.
$
CL 0285ba
AU Furbish, D.J.
DT 1985
TI The stochastic structure of a high mountain stream
SO Ph.D. dissertation, University of Colorado, Boulder, 365 pp
DE dissertation
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; stream
; NWTLTER
AB None
$
CL 1215
AU Furbish, D.J.
DT 1991
TI Spatial autoregressive structure of meander evolution
SO Geological Society of America Bulletin 103: 1576-1589.
DE NWTLTER
; hydrology
; bend migration
; bend erodibility
; convolution structure
; North Boulder Creek
AB None
$
CL 0286
AU Furbish, D.J.
; Brendecke, C.M.
; Caine, N.
; Moses, T.A.
DT 1983
TI Ablation, evaporation, and evapotranspiration in the Green Lakes Valley,
 1981-1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/3. 16
 pp.
DE Data report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Precipitation
; Snow
; Evapotranspiration
AB None
$
CL1463
AU Furbish, D.J.
; Thorne, S.D.
; Byrd, T.C. 
; Warburton, J
; Cudney, J.J.
; Handel, R.W.
DT 1998
TI Irregular bed forms in steep, rough channels-2. Field obervations
SO Water Resources Research 34:3649-3659
DE NWTLTER
AB None
$
CL 0291
AU Gates, D.M.
; Janke, R.
DT 1966
TI The energy environment of the alpine tundra
SO Oecologia Plantarum, 1:39-62
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Insolation
; Climate - Discussion of
; Bioenergetics
AB None
$
CL 0290
AU Gates, D.M.
DT 1980
TI Biophysical Ecology
SO New York: Springer-Verlag. 611 pp.
DE Ecology
; Niwot Ridge
; Insolation
; Climate - Discussion of
; Bioenergetics
AB None
$
CL 0295
AU Giesen, K.M.
; Braun, C.E.
; May. T.A.
DT 1980
TI Reproduction and nest-site selection by white-tailed ptarmigan in Colorado
SO Wilson Bulletin, 92(2):188-199
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Birds
; Reproduction
; Habitat
AB None
$
CL 0299
AU Gillette, D.A.
; Steele, A.T.
DT 1983
TI Selection of CO2 concentration data from whole-air sampling at three
 locations between 1968 and 1974
SO Journal of Geophysical Research, 88(C2):1349-1359
DE Atmospheric sciences
; NOAA GMCC
; C-1 Climate Station
; Atmospheric Chemistry
; Carbon Dioxide
AB None
$
CL 0297
AU Gillette, D.A.
DT 1983
TI Decomposition of annual patterns of atmospheric carbon dioxide
 concentrations: a preliminary interpretation of one year of data at 13
 globally distributed locations
SO Atmospheric Environment, 16:2537-2542
DE Atmospheric sciences
; NOAA GMCC
; C-1 Climate Station
; Atmospheric Chemistry
; Carbon Dioxide
AB None
$
CL 0298
AU Gillette, D.A.
; Hansen, K.J.
DT 1983
TI Sampling strategy to obtain data used in models of global annual CO2
 increase and global carbon cycle
SO Journal of Geophysical Research, 88(C2):1345-1348
DE Model
; Technique
; Atmospheric sciences
; NOAA GMCC
; C-1 Climate Station
; Atmospheric Chemistry
; Carbon Dioxide
AB None
$
CL 0299a
AU Gleason, K.J.
; Krantz, W.B.
; Caine, N.
; George, J.H.
; Gunn, R.D.
DT 1986
TI Geometrical aspects of sorted patterned ground in recurrently frozen soil
SO Science, 232:216-220
DE article
; geomorphology
; soil sciences
; Boulder City Watershed
; periglacial
; soil
; frost
; permafrost
AB None
$
CL 0302
AU Goldan, P.D.
; Kuster, W.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
; Connell, P.S.
; Norton, R.B.
; Huebert, B.J.
DT 1983
TI Calibration and tests of the filter-collection method for measuring
 clean-air, ambient levels of nitric acid
SO Atmospheric Environment, 17:1355-1364
DE Technique
; Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Nitrogen
AB None
$
CL 0306
AU Golian, S.C.
; Whitworth, M.R.
DT 1985
TI Growth of pikas (Ochotona princeps) in Colorado
SO Journal of Mammalogy, 66:367-371
DE Biology
; Long-Term Ecological Research Program
; Niwot Ridge
; Lagomorphs
; Growth (Development)
; NWTLTER
AB None
$
CL 0305
AU Golian, S.C.
; Southwick, C.H.
; Halfpenny, J.C.
DT 1984
TI Population dynamics of pikas: effects of snowpack and vegetation
SO Journal Colorado-Wyoming Academy of Sciences, 16(1):10. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Lagomorphs
; Snow
; Demography
; Reproduction
; Habitat
AB None
$
CL 0303
AU Golian, S.C.
; Southwick, C.H.
DT 1985
TI Population dynamics of pikas: Effects of snowpack and vegetation
SO In: Fuller, W.A., Nietfield, M.T., and Harris, M.A. (eds.), Abstracts of
 Papers and Posters, Fourth International Theriological Congress, Edmonton,
 13-20 August, 1985. Abstract No. 240, Session W08. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Plant
; Lagomorphs
; Snow
; Demography
; Food Habits
; Nutrition
; Reproduction
AB None
$
CL 0304
AU Golian, S.C.
; Southwick, C.H.
; Halfpenny, J.C.
DT 1984
TI Effects of snowpack and vegetation on the population dynamics of pikas
 (Ochotona princeps)
SO Bulletin of Ecological Society of America, 65(2):95 Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
;
2000
 Lagomorphs
; Snow
; Demography
; Reproduction
; Habitat
AB None
$
CL 0302a
AU Golian, S.C.
DT 1985
TI Population dynamics of pikas: effects of snowpack and vegetation
SO Ph.D. dissertation, University of Colorado, Boulder, 78 pp
DE dissertation
; ecology
; Long-Term Ecological Research Program
; Saddle
; lagomorphs
; snow
; population
; nutrition
; NWTLTER
AB None
$
CL 1386   
AU Gonzalez, G.
; Seastedt, T.R
DT 2000
TI Comparison of the abundance and composition of soil fauna in tropical and subalpine forests
SO Pedobiologia 44: 545-555.
DE None
AB None
$
CL 1441
AU Gonzalez, G.
; Seastedt, T.R.
DT 2001
TI Soil fauna and plant litter decomposition in tropical and subalpine forests
SO Ecology 82: 955-964
DE None
AB None
$
CL1552
AU Gonzalez, G.
; Seastedt, T.R.
; Donato, Z.
DT 2003
TI Earthworms, arthropods and pland litter decomposition in aspen (Populus tremuloides) and lodgepole pine (Pinus contorta) forsests in Colorado, USA
SO Pedobiologia vol. 47 pp 863-869
DE NWLTER
; undergraduate
; decomposition
; aspen
; lodgepole pine
; earthworms
; microarthropods
; subalpine forest
AB We compared the abundance and community composition of earthworms, soil macroarthropods, and litter microarthropods to test faunal effects on plant litter decomposition rates in two forests in the subalpine in Colorado, USA. Litterbags containing recently senesced litter of Populus tremuloides (aspen) and Pinus contorta (lodgepole pine) were placed in aspen and pine forests to monitor their decay rates and quantify litter microarthropod abundance. Earthworms and macroarthropods were collected by hand from the soil. Three species of earthworms were found in the aspen forest: Octolasion cyaneum, an anecic worm; Dendrobaena octaedra, an epigeic worm and Aporrectodea trapezoides, an endogeic worm. We found a higher density and fresh biomass of earthworms in the aspen (40 worms m^-2 and 4.4 g m^-2 ) than in the pine forest (0.8 worms m^-2 and 0.6 g m^-2 ). The lodgepole pine contained only earthworm species, D. octaedra. Macroarthropod density did not differ between the forests. Total density of microarthropods in the aspen and lodgepole pine forests was 6.40 and 5.24 individuals g^-1 of dry litter, respectively and did not significantly differ between forests.  The percent of mass remaining was different between litter species (r^-2 = 0.73, P < 0.01). Aspen litter decayed significantly faster than pine regardless of location. The percent of mass remaining of aspen and lodgepole pine were significantly correlated with the density of earthworms in both forests (P < 0.01). In the pine forests, the percent mass remaining of aspen and lodgepole pine litter was also significantly correlated with the density of mites (Acarina) (P = 0.03), prostigmatid mites (P = 0.02) and the total abundance of litter fauna (P = 0.02). Our results suggest that introduced earthworms play an important role on litter decomposition in the aspen forest, and that litter decomposition in these subalpine sites might be influenced differentially by various groups of soil and litter fauna.$
CL1447
AU Gonzalez, G.
; Ley, R.E.
; Schmidt, S.K.
; Zou, X.
; Seastedt, T.R.
DT 2001
TI Soil ecological interactions: comparisons between tropical and subalpine forests
SO Oecologia vol.128. pp.549-556
DE Soil fauna
; Tropics
; Subalpine
; Napthalene
; Substrate induced growth responce
AB Soil fauna can influence soil processes through interactions with the microbial community. Due to the complexity of the functional roles of fauna and their effects on microbes, little consensus has been reached on the extent to which soil fauna can regulate microbial activities. We quantified soil microbial biomass and maximum growth rates in control and fauna-excluded treatments in dry and wet tropical forests and north- and south-facing subalpine forests to test whether soil fauna effects on microbes are different in tropical and subalpine forests. Exclusion of fauna was established by physically removing the soil macrofauna and applying naphthalene. The effect of naphthalene application on the biomass of microbes that mineralize salicylate was quantified using the substrate induced growth response method. We found that: (1) the exclusion of soil fauna resulted in a higher total microbial biomass and lower maximum growth rate in the subalpine forests, (2) soil fauna exclusion did not affect the microbial biomass and growth rate in the tropical forests, and (3) the microbial biomass of salicylate mineralizers was significantly enhanced in the fauna-exclusion treatment in the tropical wet and the south-facing subalpine forests. We conclude that non-target effects of naphthalene on the microbial community alone cannot explain the large differences in total microbial biomass found between control and fauna-excluded treatments in the subalpine forests. Soil fauna have relatively larger effects on the microbial activities in the subalpine forests than in tropical dry and wet forests.$
CL 0307a
AU Goodin, D.G.
; Isard, S.A.
TI Magnitude and sources of variation in albedo within an alpine tundra
DT 1989
SO Theoretical and Applied Climatology 40:61-66
DE article
; climatology
; Mountain Research Station
; climate - discussion of
; insolation
; snow
; NWTLTER
AB None
$
CL 1382
AU Gough, L.
; Osenberg C.W.
; Gross, K.L.
; Collins, S.L.
DT 2000
TI Fertilization effects on species density and primary productivity in herbaceous 
 plant communities across latitudinal gradient
SO Oikos
DE NWTLTER
; fertilization
; species density
; species productivity
AB Fertilization experiments in plant communities are often interpreted in the 
 context of a hump-shaped relationship between species richness and productivity.  
 We analyze results of fertilization experiments from sven terrestrial plant 
 communities representing a productivity gradient (arctic and alpine tundra, 
 two old-field habitats, desert, short- and tall-grass prairie) to determine 
 the response of species richness to experimentally increased productivity is 
 consistent with the hump-shaped curve. In this analysis, we compared ratios of 
 the mean response in nitrogen-fertilized plots to the mean in control plots for 
 aboveground net primary productivity (ANPP) and species density (D; number of 
 species per plot of fixed unit area).  In general, ANPP increased and plant 
 species density decreased following nitrogen addition, although considerable 
 variation characterized the magnitude of response. 
 We also analyzed a subset of data limited to the longest running studies at 
 each site (> or equal to 4 yr), and found that adding 9 to 13 N m-2 yr-1 
 (the cosistent amount used at all sites) increased ANPP in all communities 
 by approximately 30%.  The magnitude of response of ANPP and species density 
 to fertilization was independent of initial community productivity.  There 
 was as much variation in the magnitude of response among communities within 
 sites as among sites, suggesting community-specific mechanisms of response.  
 Based on these results, we argue that even long-term fertilization experiments 
 are not good predictors of the relatively small-scale perturbations whereas 
 the pattern of species richness over natural productivity gradients is 
 influenced by long-term ecological and evolutionary processes.  
$
CL 0308
AU Graf, W.L.
DT 1976
TI Cirques as glacier locations
SO Arctic and Alpine Research, 8:79-90
DE Glaciology
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Glacier
AB None
$
CL 0309
AU Graham, J.R.
DT 1934
TI Tertiary igneous intrusions of Green Lakes and Isabelle Lake Valleys,
 Boulder County, Colorado
SO M.S. thesis, University of Colorado, Boulder. 54 pp.
DE Thesis
; Geology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0313
AU Grant, M.C.
; Mitton, J.B.
; Linhart, Y.B.
DT 1982
TI Ecological and evolutionary studies of forest trees in Colorado
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. U
2000
niversity of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37, 96-100
DE Ecology
; Genetics
; History
; Long-Term Ecological Research Program
; Conifers
; Angiosperms
; Tree
; NWTLTER
AB None
$
CL 0311
AU Grant, M.C.
; Mitton, J.B.
DT 1977
TI Genetic differentiation among growth forms of Engelmann spruce and subalpine
 fir at treeline
SO Arctic and Alpine Research, 9:259-263. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 359-363
DE Genetics
; University of Colorado
; Niwot Ridge
; Conifers
; Morphological
; Growth (Development)
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0310
AU Grant, M.C.
; Lewis, W.M., Jr.
DT 1982
TI Chemical loading rates from precipitation in the Colorado Rockies
SO Tellus, 34:74-88
DE Atmospheric sciences
; Climatology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Atmospheric Chemistry
; Acid Deposition
; Precipitation
; Stream
AB None
$
CL 0309c
AU Grant, M.C.
; Lewis, W.M.
DT 1978
TI Nutrient movement in a mountain watershed supporting light residential
 development
SO In: Lewis, G.D. (compiler), The Eisenhower Consortium for Western
 Environmental Forestry Research: Research Highlights, 1972-1980. Eisenhower
 Consortium Bulletin 8, II-17
DE Abstract
; Hydrology
; Management
; University of Colorado
; Mountain Research Station - Location
; Atmospheric Chemistry
; Chemistry
; Stream
; Water
; Biochemical
AB None
$
CL 0309b
AU Grant, M.C.
; Lewis, W.M.
DT 1977
TI Nutrient movement in a mountain watershed supporting light residential
 development
SO In: Lewis, G.D. (compiler), The Eisenhower Consortium for Western
 Environmental Forestry Research: Research Highlights, 1972-1980. Eisenhower
 Consortium Bulletin 8, II-16
DE Abstract
; Hydrology
; Management
; University of Colorado
; Mountain Research Station - Location
; Atmospheric Chemistry
; Chemistry
; Stream
; Water
; Biochemical
AB None
$
CL 0309a
AU Grant, M.C.
; Lewis, W.M.
TI Nutrient movement in a mountain watershed supporting light residential
 development
DT 1976
SO In:  Lewis, G.D. (compiler), The Eisenhower Consortium for Western
 Environmental Forestry Research: Research Highlights, 1972-1980. Eisenhower
 Consortium Bulletin 8, II-15
DE Hydrology
; Management
; University of Colorado
; Mountain Research Station - Location
; Atmospheric Chemistry
; Chemistry
; Stream
; Water
; Biochemical
AB None
$
CL 0309aa
AU Grant, W.E.
; French, N.R.
DT 1990
TI Response of alpine tundra to a changing climate: A hierarchical simulation
 model
SO Ecological Modelling 49:205-227.
DE article
; model
; ecology
; Long-Term Ecological Research Program
; Saddle
; Tracheophytes
; altitude
; climate - discussion of
; temperature
; biomass
; community
; diversity
; forest-tundra ecotone
; productivity
; NWTLTER
AB None
$
CL 0326
AU Greenland, D.
; Burbank, J.
; Key, J.
; Klinger, L.
; Moorhouse, J.
; Oaks, S.
; Shankman, D.
DT 1985
TI The bioclimates of the Colorado Front Range
SO Mountain Research and Development, 5:251-262
DE Climatology
; Ecology
; Long-Term Ecological Research Program
; Climate - Discussion of
; Distribution
; NWTLTER
AB None
$
CL 1266
AU Greenland, D.
DT 1995
TI Extreme precipitation during 1921 in the area of the Niwot Ridge
 Long-Term Ecological Research site, Front Range, Colorado, U.S.A.
SO Arctic and Alpine Research 27: 19-28
DE NWTLTER
; meteorology
; synoptic climatology
; precipitation
; world-record snowfall
; Silver Lake
; ecological effects
; alpine
; subalpine
AB An unusually high amount of precipitation, including a world record
 24-h snowfall, was recorded in 1921 at Silver Lake, Colorado, near the
 Niwot Ridge alpine tundra Long-Term Ecological Research (LTER) site.
 There was 68.3 in (1735 mm) total annual precipitation which was over
 five standard deviations above the 1914-1992 mean and the April snowfall
 produced 76 in (1.93 m) of snow in 24 h. An investigation of these
 phenomenaa brings to light the following points. The precipitation at
 Silver Lake, and presumably the Niwot Ridge LTER site, during 1921 was
 exceptionally high. The precipitation was highly localized. There are
 no obvious causes for the high precipitation to be found in the synoptic
 climatology for that year. However, moisture sources from the west in
 the winter and spring and from the south in the summer do seem to have
 been available. Despite well-marked, but temporary, impacts on humans
 and possibly other higher mammals, there is no evidence of any major
 or long-lasting impacts to the alpine tundra or subalpine forest 
 ecosystems. Higher temperatures and persistent drought, as might be
 found with global climatic warming, are proposed as potentially more
 important disturbance factors to these systems.
$
CL 0323
AU Greenland, D.
DT 1984
TI Bioclimates
SO In: Taylor, J.A. (ed.), Themes in Biogeography. London: Croom Helm, 234-253
DE Climatology
; Long-Term Ecological Research Program
; Climate - Discussion of
; Distribution
; NWTLTER
AB None
$
CL 0316a
AU Greenland, D.
DT 1986
TI Mountain climates--upland
SO In: Oliver, J.E. and Fairbridge, R.W. (eds.), The Encyclopedia of
 Climatology. New York: Van Nostrand Reinhold, 594-601
DE article
; climatology
; University of Colorado
; Long-Term Ecological Research Program
; climate - discussion of
AB None
$
CL 1209
AU Greenland, D.
DT 1989
TI The climate of Niwot Ridge, Front Range, Colorado, USA
SO Arctic and Alpine Research 21(4): 380-391
DE NWTLTER
; Niwot Ridge
; climatology
; C-1
; D-1
; precipitation
; temperature
; Silver Lake
AB None
$
CL 1211
AU Greenland, D.
; Swift, L.W., Jr. (eds.)
DT 1990
TI Climate variability and ecosystem response: Proceedings of a Long-Term
 Ecological Research Workshop. 21-23 August 1988; Boulder, CO. General
 Technical Report SE-65. Asheville, NC: USDA Forest Service, Southeastern
 Forest Experiment Station. 90 pp.
DE NWTLTER
; LTER
; climate variability
; ecosystem response
AB None
$
CL 1499
AU Greenland, D.
; Goodin, D.
; Smith, R.
DT 2003
TI Climate Variability and Ecosystem Response
SO Oxford University Press. New York. 459 pp
DE NWTLTER
AB None
$
CL 0317aa
AU Greenland, D.
DT 1986
TI Standardized meteorological measurements for Long-Term Ecological Research
 sites
SO Bulletin of the Ecological Society of America, 67:275-277
DE article
; technique
; climatology
; Long-Term Ecological Research Program
; climate - discussion of
; NWTLTER
AB None
$
CL 1213
AU Greenland, D.
; Swift, L.W., Jr.
DT 1990
TI Overview of climate variability and ecosystem response
SO Pp. 85-90 In: Greenland, D., and L.W. Swift (eds.). Climate Variability and
 Ecosystem Response: Proceedings of a Long-Term Ecological Research Workshop.
 21-23 August 1988; Boulder, CO. General Technical Report SE-65. Asheville, NC:
 USDA Forest Service, Southeastern Forest Experiment Station. 90 pp
DE NWTLTER
; LTER
; climate variability
; ecosystem response
AB None
$
CL 1217
AU Greenland, D.
; Drozdov, D.E.
DT 1991
TI Monitoring environmental change 2. Surface measurements and field studies
SO Pp. 199-217 In: Mather, J.R., and G.V. Sdasyuk (eds.). Global Change:
 Geographical Approaches. Tucson: University of Arizona Press. 289 pp
DE NWTLTER
; global change
; climate change
; data storage
; data analysis
; GIS
AB None
$
CL 1236
AU Greenland, D.
DT 1993
TI Spatial energy budgets in alpine tundra
SO Theoretical and Applied Climatology 46: 229-239
DE NWTLTER
; modelling
; GIS
; surface heat
; energy budget
; Niwot Ridge Saddle
; albedo
; soil heat flux
; latent heat flux
AB Modelling and geographic information system (GIS) technology are employed in
 order to extend spatially, estimated and observed growing season values of the
 components of the surface heat energy budget for an area of alpine tundra in
 the Colorado Front Range. A surface equilibrium temperature model is
 calibrated for
2000
 one sub-class of vegetation surface and is used to model
 surface heat energy budget component values for other sub-classes of
 vegetation. The model values compare favorably with values independently
 estimated or observed. The data are spatially displayed using the Idrisi GIS.
 At the microclimatic scale the presence of different sub-classes of vegetation
 plays a large role in controlling the actual values of the surface heat budget
 components. This is in contrast to the larger scale at which climatic
 variables such as air temperature control the overall vegetation type found in
 the area.
$
CL 1486
AU Greenland, D.
; Hayden, B.P.
; Magnuson, J.J.
; Ollinger, S.V.
; Pielke Sr., R.A.
; Smith, R.C.
DT 2003
TI Long-Term Research on Biosphere-Atmosphere Interactions
SO Bioscience v. 53 no. 1 pp. 33-45
DE NWTLTER
; atmosphere
; climate
; biosphere
; ice
; land use
AB Selected findings from the Long Term Ecological Research (LTER) program are described in the field of biosphere-atmosphere interactions. The Palmer, Antarctic, site contributes evidence to the debate on the ecological effects of increased ultraviolet-B radiation; the ecological response to a warming trend over the past half-century has been clearly documented there. The North Temperate Lakes site in Wisconsin was the principal LTER site for an international study to document a 100-year trend of change in freeze and thaw dates of boreal lakes. A multidisciplinary approach to soil warming studies benefited from observations over decades and demonstrated the importance of initial conditions. The LTER Network permits investigation of atmosphere-ecosystem interactions over a long period encompassing storm events and quasi-periodic climate variability. LTER studies show that ecosystem dynamics often cannot be decoupled from atmospheric processes. Atmospheric processes are an integral component of the ecosystem and vice versa. Finally, we provide an example of how regionalization studies, often grounded in atmospheric data, add a spatial context to LTER sites and identify controls on ecological processes across broader environmental gradients.
$
CL 1504
AU Greenland, D.
; Goodin, D.G.
; Smith, R.C.
; Swanson, F.J.
DT 2003
TI Climate variability and ecosystem response - Synthesis
SO Climate Variability and Ecosystem Response. Greenland, D., D. Goodin, and R. Smith (Eds). Oxford University Press. New York
DE NWTLTER
AB None
$
CL 1500
AU Greenland, D.
; Goodin, D.
; Smith, R.
DT 2003
TI An introduction to climate variability and ecosystem response.
SO Climate Variability and Ecosystem Response. Greenland, D., D. Goodin, and R. Smith (Eds). Oxford University Press. New York
DE NWTLTER
AB None
$
CL 1501
AU Greenland, D.
DT 2003
TI Short-Term climate events- Synthesis
SO Climate Variability and Ecosystem Response. Greenland, D., D. Goodin, and R. Smith (Eds). Oxford University Press. New York
DE NWTLTER
AB None
$
CL1480
AU Greenland, D.
; Kittel, T.G.F.
DT 2002
TI Temporal variability of climate at the US Long-Term Ecological Research (LTER) sites
SO Climate Research v. 19 pp. 213-231
DE NWTLTER
; climate variability
; climatic trends
; LTER
; United States
; Puerto Rico
; Antarctica
AB We examine the temporal climate variability of 18 Long-Term Ecological Research (LTER) sites in the United States including Puerto Rico and Antarctica. Annual and seasonal means of air temperature and totals of precipitation were collected from sites for the period 1957-1990 and, for some sites, for longer periods ranging up to a century, Fourteen of the sites show a positive trend in annual mean temperature during the 1957-1990 period, while 4 show a negative trend. Statistical evidence exists at some groups of sites for a step function in temperature and precipitation occurring in the 14 yr either side of 1976. Comparisons suggest that with respect to changes in time, the climates of sites in the North Central part of the US tend to act in concert as one group while the climates of sites near the East Coast tend to act together as a separate group. The climates of the Antarctic sites also seem to act in a coherent manner, There is less coherence among the climates of other LTER sites. These patterns are shown in the variations of the detrended standardized 5 yr moving averages of temperature and precipitation at the sites. The patterns are associated with variations in the values of teleconnective indices, particularly the North Atlantic Oscillation index for the North Central and East Coast LTER sites and the Pacific North American index for the Alaskan and Pacific Northwest group of LTER sites. The climates of some sites, such as those in the center of the country, show some evidence of 'cyclicity' but the record length is too short to make definitive statements about this. We review the variability of some ecological effects that have been documented at LTER sites as this variability relates to the described climate.$
CL 1235
AU Greenland, D.
DT 1993
TI Climate studies in the Long-Term Ecological program
SO Pp 5-11 In: Redmond, K.T., and V.L. Tharp (eds.) Proceedings of the Ninth
 Annual Pacific Climate (PACLIM) Workshop. Technical Report 34 of the
 Interagency Ecological Studies Program for the Sacramento-San Joaquin Estuary.
 Sacramento: California Department of Water Resources. 194 pp
DE NWTLTER
; climatology
; LTER
; meteorology
; climate variability
; ecosystem response
AB Since the inception of the LTER Program in 1980, climate has been studied at
 individual LTER sites and a LTER Climate Committee has been responsible for
 inter-site activities. At individual sites, climate studies support ecological
 research, emphasize intra-site heterogeneity, and often relate to other
 national monitoring and research programs. In inter-site work, the Climate
 Committee has produced protocols for meteorological observations, described
 and compared climates of the first 11 sites, and raised important issues
 regarding climate variability and ecosystem response.
$
CL 0315b
AU Greenland, D.
DT 1986
TI Energy budget climatology
SO In: Oliver, J.E. and Fairbridge, R.W. (eds.), The Encyclopedia of
 Climatology. New York: Van Nostrand Reinhold, 414-421
DE article
; climatology
; University of Colorado
; Long-Term Ecological Research Program
; energy budget
; climate - discussion of
AB None
$
CL 1431
AU Greenland, D.
; Losleben, M.V.
DT 2001
TI Climate
SO Chapter 2 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 0329
AU Greenland, D.
; Daly, C.
DT 1985
TI Microclimate data from the Saddle, Niwot Ridge, Summer - 1984
SO University of Colorado Long-Term Ecological Research Data Report, 85/4. 82
 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Climate - Discussion of
; Climate - Data Included
AB None
$
CL 1216
AU Greenland, D.
; Swift, L.W., Jr.
DT 1991
TI Climate variability and ecosystem response: Opportunities for the LTER
 Network
SO Bulletin of the Ecological Society of America 72(2): 118- 126
DE NWTLTER
; air mass
; climate change
; LTER
; scale
AB None
$
CL 1210
AU Greenland, D.
DT 1990
TI Climate variability at Niwot Ridge in the twentieth century
SO Pp. 59-66 In: Greenland, D., and L.W. Swift (eds.). Climate Variability and
 Ecosystem Response: Proceedings of a Long-Term Ecological Research Workshop.
 21-23 August 1988; Boulder, CO. General Technical Report SE- 65. Asheville,
 NC: USDA Forest Service, Southeastern Forest Experiment Station. 90 pp
DE NWTLTER
; Niwot Ridge
; C-1
; D-1
; Silver Lake
; climate change
; climate analysis
; LTER
; ecosystem response
AB None
$
CL 0317b
AU Greenland, D.
DT 1991
TI Surface energy budgets over alpine tundra in summer
SO Mountain Research and Development 11(4):339-351
DE article
; climatology
; Long-Term Ecological Research Program
; Saddle
; climate - data
; insolation
; energy budget
; NWTLTER
AB None
$
CL 1203
AU Greenland, D.
DT 1986
TI Preliminary r
2000
esults of NADP sampling on Niwot Ridge, Colorado
SO In: Pielke, R.A. (ed.), Proceedings of Symposium on acid deposition in
 Colorado - a potential or current problem; Local versus long-distance
 transport in the state.  Colorado State University, Pingree Park Campus,
 August 13-15, 1986.  Fort Collins, Colorado: Cooperative Institute for
 Research in Atmospheric Sciences, 75-102
DE NWTLTER
; acid deposition
; NADP
; Niwot Ridge
AB None
$
CL 0320
AU Greenland, D.
DT 1983
TI Summer microclimatic observations over alpine tundra
SO Journal of the Colorado-Wyoming Academy of Sciences. 15(1):37. Abstract
DE Abstract
; Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Climate - Discussion of
AB None
$
CL 1498
AU Greenland, D.
DT 2002
TI Climate variability and ecosystem response at Long-Term Ecological Research sites
SO Proceedings of the 15th Conference on Biometeorology and Aerobiology joint with the 16th International Conference on Biometeorology. 27 October - 1 November, 2002. Kansas City MO. American Meteorological Society, Boston, MA. pp. 317-318
DE NWTLTER
AB none 
$
CL 1503
AU Greenland, D.
DT 2003
TI Introductory overview (to climate variability and ecosystem response at selected LTER sites at multiple timescales)
SO Climate Variability and Ecosystem Response. Greenland, D., D. Goodin, and R. Smith (Eds). Oxford University Press. New York
DE NWTLTER
AB None
$
CL 1380
AU Greenland, D.
DT 1999
TI ENSO-related phenomena at long-term ecological reasearch sites
SO Physical Geography 20:491-507.
DE NWTLTER
; El Nino-Southern Oscillation even
; ENSO
; climate variability
; La-Nina
AB I outline a framework for investigating and discussing climate variability 
 and ecosystem response.  The example of an El Nino-Southern Oscillation (ENSO) 
 event is a relatively simple one for operationalizing this framework.  I review 
 some of the earlier findings related to El Ninos and Long-Term Ecological Research 
 (LTER) sites.  Then I perform an analysis for the period 1957 to 1990 investigating 
 the response of monthly mean temperature and monthly total precipitation standardized 
 anomaly values to El Nino and La Nina events as indicated by the Southern Oscillation 
 Index (SOI).  Different LTER sites manifest strong, detectable, and weak or no climatic 
 signals to El Nino and La Nina events.  Some of the effects of the ENSO-related climate 
 variability on selected ecosystems are discussed.  A statistically significant climate 
 signal at an LTER site does not necessarily mean there will be an ecologically significant 
 response.  El Nino signals in the temperature series at the Andrews Forest, Oregon, the 
 Luquillo Rain Forest, Puerto Rico, and the Palmer, Antarctic (PAL), sites are found to 
 be statistically the strongest.  Of these, only the signal at the PAL site has an important 
 ecological effect.  Somewhat less statistically strong ENSO signals at the Northern 
 Temperate Lakes, Wisconsin, and the Sevilleta, New Mexico, sites have important 
 ecological effects.  An analysis of the climatic response to the 1982/1983 "super El Nino" 
 compared to more normal size warm events is equivocal.  The results of the correlation 
 analysis are discussed within the climate variability/ecosystem response framework 
 previously outlined.  The timing of the ENSO event and the identification of an 
 ecosystem coupling mechanism are critical for this particular form of climate 
 variability to have an effect.  
$
CL 0316b
AU Greenland, D.
DT 1987
TI The radiation balance
SO In: Gregory, K.J. and Walling, D.E. (eds.), Human Activity and Environmental
 Processes. New York: John Wiley, 15-30.
DE article
; climatology
; Long-Term Ecological Research Program
; anthropogenic
; insolation
; energy budget
; insolation
; climate - discussion of
AB None
$
CL 1212
AU Greenland, D.
; Swift, L.W., Jr.
DT 1990
TI Introduction
SO Pp. 1-2 In: Greenland, D., and L.W. Swift (eds.). Climate Variability and
 Ecosystem Response: Proceedings of a Long-Term Ecological Research Workshop.
 21-23 August 1988; Boulder, CO. General Technical Report SE-65. Asheville, NC:
 USDA Forest Service, Southeastern Forest Experiment Station. 90 pp
DE NWTLTER
; LTER
; climate variability
; ecosystem response
AB None
$
CL 0327
AU Greenland, D.
; Caine, N.
; Pollak, O.
DT 1984
TI The summer water budget and its importance in the alpine tundra of Colorado
SO Physical Geography, 5:221-239
DE Climatology
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Spermopsida
; Water
; Evapotranspiration
; NWTLTER
AB None
$
CL 1502
AU Greenland, D.
DT 2003
TI An LTER Network overview and introduction to El Nino-Southern Oscillation (ENSO) climatic signal and response
SO Climate Variability and Ecosystem Response. Greenland, D., D. Goodin, and R. Smith (Eds). Oxford University Press. New York
DE NWTLTER
AB None
$
CL 0329a
AU Greenland, D. (ed.)
; Swift, L.W. Jr. (ed.)
DT 1990
TI Response of alpine tundra to a changing climate: a hierarchical simulation
 model
SO Ecological Modelling 49:205-227
DE article
; model
; ecology
; Long-Term Ecological Research Program
; climate - discussion of
; climate change
AB None
$
CL 0315a
AU Greenland, D. (ed.)
DT 1987
TI The climates of the Long-Term Ecological Research sites
SO University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper 44. 81 pp
DE article
; climatology
; Long-Term Ecological Research Program
; Niwot Ridge
; climate - discussion of
; NWTLTER
AB None
$
CL 0317a
AU Greenland, D.E.
DT 1980
TI Atmospheric dispersion in a mountain valley
SO Annals of the Association of American Geographers, 70(2):199-205
DE Atmospheric Sciences
; Climatology
; Model
; Mountain Research Station - Location
; Wind
AB None
$
CL 0328
AU Greenland, D.E.
; Daly C.
DT 1983
TI Microclimate data from the Saddle Area, Niwot Ridge, Summer - 1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/8. 36
 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0316
AU Greenland, D.E.
DT 1977
TI Living on the 700 mb surface: The Mountain Research Station of the Institute
 of Arctic and Alpine Research
SO Weatherwise, 30(6):232-238
DE Climatology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0325A
AU Greenland, D.E.
DT 1987
TI The climate of Niwot Ridge
SO University of Colorado Long-Term Ecological Research Data Report 87/7. 57 pp
DE Data Report
; Climatology
; Long-Term Ecological Research Program
; D-1 Climate Station
; C-1 Climate Station
; Saddle (Niwot Ridge)
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0318
AU Greenland, D.E.
DT 1982
TI Air quality and surface energy budget
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37, 23-25
DE Overview
; Atmospheric sciences
; Climatology
; Long-Term Ecological Research Program
; Atmospheric Chemistry
; Insolation
; NWTLTER
AB None
$
CL 0319
AU Greenland, D.E.
DT 1983
TI Energy balance instrumentation
SO University of Colorado Long-Term Ecological Research Working Paper, 83/1. 18
 pp.
DE Data report
; Technique
; Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Insolation
AB None
$
CL 0322
AU Greenland, D.E.
DT 1983
TI The theoretical basis for energy budget measurements on Niwot Ridge
SO University of Colorado Long-Term Ecological Research Working Paper, 83/2. 23
 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Insolation
; Climate - Discussion of
AB None
$
CL 0324
AU Greenland, D.E.
DT 1984
TI Energy budgets over a moisture gradient in alpine tundra
SO Paper presented to ann
2000
ual meeting of the Association of American
 Geographers. Washington, D.C., April 22-25, 1984
DE Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Climate - Data Included
; Water
; Climate - Discussion of
AB None
$
CL 0325
AU Greenland, D.E.
DT 1984
TI The use of the water budget to specify ecological conditions in the alpine
 tundra of Colorado
SO Paper presented at the 25th International Geographical Congress. Paris,
 France. August 25-31, 1984
DE Climatology
; Ecology
; Hydrology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Water
AB None
$
CL 0321
AU Greenland, D.E.
DT 1983
TI Summer microclimate observations over alpine tundra
SO University of Colorado Long-Term Research Working Paper, 83/5. 18 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0317
AU Greenland, D.E.
DT 1978
TI Spatial distribution of radiation in the Colorado Front Range
SO Climatological Bulletin, 24:1-14. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 302-315
DE Climatology
; Mountain Research Station - Affiliation
; A-1 Climate Station
; Insolation
AB None
$
CL 0331
AU Greenstein, L.A.
DT 1983
TI An investigation of midlatitude alpine permafrost on Niwot Ridge, Colorado
 Rocky Mountains, USA
SO Permafrost Fourth International Conference Proceedings, Fairbanks, July
 17-22, 1983. Washington, DC: National Academy Press, 380-383
DE Climatology
; Geomorphology
; Mountain Research Station - Affiliation
; Saddle, Niwot Ridge
; Permafrost
; Climate - Discussion of
AB None
$
CL 0330
AU Greenstein, L.A.
DT 1983
TI Alpine permafrost on Niwot Ridge based on indirect locational techniques
SO M.A. thesis, University of Colorado, Boulder. 103 pp.
DE Thesis
; Technique
; Climatology
; Geomorphology
; Mountain Research Station - Affiliation
; Saddle, Niwot Ridge
; Permafrost
; Climate - Discussion of
AB None
$
CL 0335
AU Greller, A.M.
DT 1974
TI Vegetation of roadcut slopes in the tundra of Rocky Mountain National Park,
 Colorado
SO Biological Conservation, 6(2):84-93
DE Ecology
; Management
; Mountain Research Station - Affiliation
; Rocky Mountain National Park - Location
; Angiosperms
; Distribution
; Disturbances
; Succession
; Revegetation
AB None
$
CL 0336
AU Greller, A.M.
; Goldstein, M.
; Marcus, L.
DT 1974
TI Snowmobile impact on three alpine tundra plant communities
SO Environmental Conservation, 1(2):101-110
DE Ecology
; Management
; Niwot Ridge
; Angiosperms
; Community
; Disturbances
AB None
$
CL 0340
AU Groeneveld, D.P.
; Krebs, P.V.
DT 1974
TI Forest cover-type mapping using color infrared aerial photography
SO Journal Colorado-Wyoming Academy of Science, 7(5):46. Abstract
DE Abstract
; Map
; Ecology
; Remote sensing
; NASA - PY
; Niwot Ridge
; Distribution
; Conifers
AB None
$
CL 1358
AU Groffman, P.M.
; Holland, E.A.
; Myrold, D.D.
; Robertson, G.P.
DT 1999
TI Denitrification
SO In Robertson, G.P. et al. (eds.) Standard Soil Methods for Long-Term Ecological Research.
 Oxford Press. Pp. 272-290
DE NWTLTER
; denitrification
; soil
AB None
$
CL 1373
AU Gross, K.L.
; Willig, M.R.
; Gough, L.
; Inouye R.
; Cox, S.B.
DT 2000
TI Patterns of species density and productivity at different spatial
 scales in herbaceous communitites
SO Oikos 89:417-427
DE NWTLTER
; species density
; species productivity
; species richness
; plant community
AB A major challenge in evaluating patterns of species richness and productivity 
 involves acquiring data to examine these relationships empirically across a 
 range of ecologically significant spatial scales. In this paper, we use data 
 from herb-dominated plant communities at six Long-Term Ecological Research 
 (LTER) sites to examine how the relationship between plant species density and
 above-ground net primary productivity (ANPP) differs when the spatial scale of 
 analysis is changed. We quantified this relationship at different spatial scales 
 in which we varied the focus and extent of analysis: (1) among fields within 
 communities, (2) among fields within biomes or biogeographic regions, and (3) 
 among communities within biomes or biogeographic regions. We used species density 
 (D=number of species per square meter) as our measure of diversity to have a comparable
 index across all sites and scales. Although we expected unimodal relationships at 
 all spatial scales, we found that spatial scale influenced the form of the relationship. 
 At the scale of fields within different grassland communities, we detected a significant 
 relationship at only one site (Minnesota old-fields), and it was negative linear. When 
 we expanded the extent of analyses to biogeographic regions (grasslands or North America),
 we found significant unimodal relationships in both cases. However, when we combined 
 data to examine patterns among community types within different biogeographic regions 
 (grassland, alpine tundra, arctic tundra, or North America), we did not detect significant 
 relationships between species density and ANPP for any region. The results of our 
 analyses demonstrate that the spatial scale of analysis - how data are aggregated and 
 patterns examined - can influence the form of the relationship between species density 
 and productivity. It also demonstrates the need for data sets from a broad spectrum 
 of sites sampled over a range of scales for examining challenging and controversial 
 ecological hypotheses.
$
CL 0341
AU Grulke, N.E.
DT 1978
TI Vegetational regeneration fifty years after fire in the Front Range,
 Colorado
SO B.S. thesis, Department of Botany, Trinity College of Duke University. 65
 pp.
DE Thesis
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Conifers
; Angiosperms
; Fire
; Revegetation
AB None
$
CL 0342
AU Gurnell, J.
DT 1984
TI Home range, territoriality, caching behaviour and food supply of the red
 squirrel (Tamiasciurus hudsonicus fremonti) in a subalpine lodgepole pine
 forest
SO Animal Behavior, 32:1119-1131
DE Behavior
; Ecology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Mammals
; Conifers
; Food Habits
AB None
$
CL 0343
AU Gustafson, D.
DT 1965
TI The geology of the Lake Isabelle area, Boulder County, Colorado
SO M.S. thesis, University of Colorado, Boulder. 100 pp.
DE Thesis
; Geology
; University of Colorado
; Indian Peaks Region
AB None
$
CL 0344
AU Haase, R.
DT 1983
TI Verbreitungsmuster und Standorte der Aplinen Vegetation in der Indian Peaks
 Area, Colorado Front Range, U.S.A.
SO Ph.D. dissertation, University of Munster, West Germany
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Angiosperms
; Distribution
AB None
$
CL 0344a
AU Haase, R.
DT 1987
TI An alpine vegetation map of Caribou Lake Valley and Fourth of July Valley,
 Front Range, Colorado, USA
SO Arctic and Alpine Research, 19(1):1-10
DE Ecology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Map
; Snow
; Topography
; Wind
; Community
; Distribution
; Phytosociology
; Plants
; Forest Tundra Ecotone (Timberline)
AB None
$
CL 0346
AU Hadley, N.F.
DT 1969
TI Microenvironmental factors influencing the nesting sites of some subalpine
 fringillid birds in Colorado
SO Arctic and Alpine Research, 1:121-126
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mountain Research Station - Location
; Birds
; Climate - Discussion of
; Habitat
AB None
$
CL 0345
AU Hadley, N.F.
DT 1966
TI Microenvironmental factors influencing the nesting sites of some Colorado
 subalpine Fringillidae
SO Ph.D. dissertation, University of Colorado, Boulder. 86 pp.
DE Dissertation
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Birds
; Mountain Research Station - Location
; Habitat
; Climate - Discussion of
AB None
$
CL 0347
AU H
2000
aefner, B.D.
DT 1974
TI Glacial valley morphometry in the Front Range of Colorado
SO M.A. thesis, University of Colorado, Boulder. 103 pp.
DE Thesis
; Geomorphology
; Institute of Arctic and Alpine Research
; Glacier
AB None
$
CL 0348
AU Halford, M.K.
DT 1983
TI Analysis of the structure of herbaceous communities along an elevational
 gradient in the Colorado Front Range
SO M.A. thesis, University of Colorado, Boulder. 145 pp.
DE Thesis
; Ecology
; Mountain Research Station - Affiliation
; A-1 Climate Station
; Angiosperms
; Altitude
; Community
AB None
$
CL 1223
AU Halfpenny, J.C.
DT 1992
TI Environmental impacts of powdertracking using fluorescent pigments
SO Journal of Mammalogy 73: 680-682
DE NWTLTER
; fluorescent pigments
; environmental contamination
; Niwot Ridge
AB Tests revealed long-term persistence of pigments and the potential for
 environmental contamination. Primary persistence of pigments falling from
 animals lasted through the melting of 3-m-deep snowpacks, summer rains, and
 winds for at least 2 years. Secondary persistence included transfer of
 pigments to non-test animals, and concentration and incorporation into scat
 and woodrat middens. Feces persist in middens extending potential
 contamination up to 40,000 years. Since the potential for long-term,
 environmental contamination exists, researchers should carefully consider
 initial application techniques, clean up methods, and residual visual and
 ultraviolet visual contamination.
$
CL 0351
AU Halfpenny, J.C.
DT 1982
TI Introduction: The University of Colorado Long-Term Ecological Program
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37, ix-xiii
DE Overview
; Ecology
; Long-Term Ecological Research Program
; NWTLTER
AB None
$
CL 0361
AU Halfpenny, J.C.
; Pollak, O.
; Heffernan, M.W.
DT 1984
TI Snowpack patterns in the alpine tundra, Niwot Ridge, Colorado
SO Proceedings International Snow Science Workshop: A Merging of Theory and
 Practice. Aspen, Colorado, October 24-27, 1984, 155-160
DE Ecology
; Hydrology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Snow
; Distribution
; Angiosperms
AB None
$
CL 0356
AU Halfpenny, J.C.
; Ingraham, K.P.
; Adams, J.A.
; Pekar, H.
DT 1983
TI Mountain Research Station: Its Environment and Research
SO University of Colorado, Institute of Arctic and Alpine Research. 20 pp.
DE Guide
; Climatology
; Ecology
; Geology
; History
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
AB None
$
CL 0351a
AU Halfpenny, J.C.
; Clark, J.
DT 1988
TI Climate calendars
SO BioScience, 38:399-405
DE Journal
; Climatology
; Data Management
; Long-Term Ecological Research Program
; A-1 to D-1 Climate Stations
; Niwot Ridge
; Climate - Discussion of
; Temperature
; NWTLTER
AB None
$
CL 0353
AU Halfpenny, J.C.
; Ingraham, K.P.
DT 1983
TI Growth and development of heather voles
SO Growth, 47:437-445
DE Biology
; Long-Term Ecological Research Program
; Niwot Ridge
; Rodents
; Growth (Development)
; NWTLTER
AB None
$
CL 0357
AU Halfpenny, J.C.
; Ingraham, K.
; Southwick, C.H.
; Golian, S.C.
; Hause, H.L.
; Meany, C.
DT 1984
TI Ecological data on small mammal herbivores from the Colorado alpine tundra,
 1981 - 1983
SO University of Colorado Long-Term Ecological Research Data Report, 84/7. 63
 pp.
DE Data report
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Lagomorphs
; Rodents
; Distribution
; Demography
; Biomass
; Reproduction
AB None
$
CL 0364
AU Halfpenny, J.C.
; Pollak, O.D.
; Ingraham, K.P.
; Rink, L.P.
; Heffernan, M.W.
DT 1984
TI Summer and winter phenologies for alpine tundra
SO Journal Colorado-Wyoming Academy of Sciences, 16(1):10. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Insects
; Birds
; Mammals
; Climate - Data Included
; Climate - Discussion of
; Phenological (seasonal)
AB None
$
CL 1224
AU Halfpenny, J.C.
; Heffernan, M.
DT 1992
TI Nutrient input to an alpine tundra: An aeolian insect component
SO The Southwestern Naturalist 37: 247-251
DE NWTLTER
; windblown insects
; Loxstege cerareoles
; nutrient input
; phosphorus
; potassium
; nitrogen
; fertilizer
; Niwot Ridge
AB Large quantities of non-alpine insects are blown episodically onto some
 alpine tundras. These events may have return intervals as short as 3 years in
 Colorado. Windblown depositions of a moth (Loxstege cerareoles, Pyralidae)
 from one episodic event were analyzed to determine the possible influx of
 soluble nutrients to the alpine tundra. Ten chemicals were identified in or on
 the insect bodies. Significant external additions of soluble phosphorus and
 potassium occurred to the alpine, but additions of soluble nitrogen were
 probably not significant. Phosphorus additions may represent a relatively new
 input source emanating from contamination by fertilizers used on alfalfa crops
 on the Great Plains. Potassium inputs may originate in the soils of the Great
 Plains and may increase buffering capacity in the poorly buffered tundra soils
 of the Colorado Front Range.
$
CL 0362
AU Halfpenny, J.C.
; Pollak, O.D.
; Hibbard, K.A.
; Rink, L.P.
; Heffernan, M.W.
DT 1984
TI An ecosystem phenology for alpine tundra, Niwot Ridge, Colorado
SO New Mexico Journal of Science, 24(1):45-46. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Insects
; Birds
; Mammals
; Climate - Data Included
; Climate - Discussion of
; Phenological (seasonal)
AB None
$
CL 0358
AU Halfpenny, J.C.
; Pollak, O.
DT 1983
TI Snow survey data from the Saddle, Niwot Ridge, Colorado, 1981-1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/9. 53
 pp.
DE Data report
; Hydrology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Snow
AB None
$
CL 0366
AU Halfpenny, J.C.
; Southwick, C.H.
; Golian, S.
; Meaney, C.
; Ingraham, K.
; Hause, H.
DT 1983
TI Mammalian herbivore biomass in the Colorado alpine tundra
SO Journal Colorado-Wyoming Academy of Sciences, 15(1):50. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Mammals
; Climate - Discussion of
; Biomass
AB None
$
CL 0359
AU Halfpenny, J.C.
; Pollak, O.
; Heffernan, M.W.
DT 1984
TI Snowpack patterns in the alpine tundra, Niwot Ridge, Colorado
SO Pp 155-160 In Proceedings of the International Snow Science 
 Workshop: A Merging of Theory and Practice, Aspen, CO, 24-27 October 
 1984
DE Hydrology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Snow
; NWTLTER
AB None
$
CL 0349
AU Halfpenny, J.C.
DT 1980
TI Reproductive strategies: Intra- and inter-specific comparison within the
 genus Peromyscus
SO Ph.D. dissertation, University of Colorado, Boulder. 160 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Rodents
; Altitude
; Demography
; Reproduction
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0365
AU Halfpenny, J.C.
; Southwick, C.H.
DT 1982
TI Small mammal herbivores of the Colorado alpine tundra
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37, 111-123
DE Overview
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Rodents
; Lagomorphs
; Demography
; Distribution
; Food Habits
; Reproduction
; NWTLTER
AB None
$
CL 0355
AU Halfpenny, J.C.
; Ingraham, K.P.
; Adams, J.A.
DT 1983
TI Working atlas for the Saddle, Niwot Ridge, Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Data Report, 83/1. 24
 pp.
DE Data report
; Map
; 
2000
Ecology
; Management
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Distribution
AB None
$
CL 0356a
AU Halfpenny, J.C.
; Ingraham, K.P.
; Mattysse, J.
; Lehr, P.J.
DT 1985
TI Bibliography for alpine and subalpine areas of the Colorado Front Range
SO University of Colorado Long-Term Ecological Research Working Paper 85/2. 68
 pp
DE Data Report
; Bibliography
; Geoecology
; Ecology
; Long-Term Ecological Research Program
AB None
$
CL 0356b
AU Halfpenny, J.C.
; Ingraham, K.P.
; Mattysse, J.
; Lehr, P.C.
DT 1986
TI Bibliography of alpine and subalpine areas of the Front Range, Colorado
SO Institute of Arctic and Alpine Research Occasional Paper 43. University of
 Colorado, Boulder, 114 pp.
DE bibliography
; overview
; Long-Term Ecological Research Program
; NWTLTER
AB None
$
CL 0363
AU Halfpenny, J.C.
; Pollak, O.D.
; Hibbard, K.A.
; Rink, L.P.
; Ingraham, K.P.
; Heffernan, M.W.
DT 1984
TI Ecosystem phenology for alpine tundra, Front Range, Colorado
SO Bulletin of Ecological Society of America, 65(2):247
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Insects
; Birds
; Mammals
; Climate - Data Included
; Climate - Discussion of
; Phenological (seasonal)
AB None
$
CL 0364a
AU Halfpenny, J.C.
; Schmitt, M.
; Warburton, J.
; Heffernan, M.W.
; Auerbach, N.A.
DT 1986
TI Topographic and three dimensional relief maps for the Saddle, Niwot Ridge,
 Colorado
SO University of Colorado Long-Term Ecological Research Data Report 86/4. 16 pp
DE Data Report
; Geology
; Geographic Information Systems
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Altitude
; Map
AB None
$
CL 0352
AU Halfpenny, J.C.
; Heffernan, M.W.
DT 1985
TI Summer temperature analysis for the Saddle, Niwot Ridge, Colorado. Front
 Range - 1981-1984
SO University of Colorado Long-Term Ecological Research Data Report, 85/1. 21
 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; D-1 Climate Station
; Saddle, Niwot Ridge
; Temperature
AB None
$
CL 0354
AU Halfpenny, J.C. (ed.)
; Ingraham, K.P. (ed.)
DT 1984
TI Long-Term Ecological Research in the United States: A Network of Research
 Sites. 28 pp.
DE Overview
; Guide
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
AB None
$
CL 0350
AU Halfpenny, J.C. (ed.)
DT 1982
TI Ecological Studies in the Colorado Alpine: A Festschrift to John W. Marr
SO University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper 37. 147 pp.
DE Overview
; Ecology
; Long-Term Ecological Research Program
; NWTLTER
AB None
$
CL 0367
AU Halleck, D.K.
DT 1974
TI Environmental and hormonal control of flowering in Sedum lanceolatum Torr.
 (Crassulaceae)
SO Ph.D. dissertation, University of Colorado, Boulder. 221 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Climate - Discussion of
; Physiological
; Phenological (seasonal)
; Angiosperms
AB None
$
CL 0368
AU Halleck, D.K.
; Wiens, D.
DT 1966
TI Taxonomic status of Claytonia rosea and C. lanceolata (Portulacaceae)
SO Annals, Missouri Botanical Garden, 53(2):205-212
DE Taxonomy and systematics
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
AB None
$
CL 1403
AU Hamann, H.B.
DT 1998
TI Snowcover controls on alpine soil surface temperature patters, Niwot Ridg   e, Colorado, USA
SO M.S. Thesis, University of Colorado, Boulder 170 pp.
DE NWTLTER 
AB None
$
CL 0370
AU Hansen, K.J.
DT 1978
TI Forest-tundra ecotone, Niwot Ridge, Colorado
SO Association of American Geographers Program Abstracts. New Orleans. Abstract
DE Abstract
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Conifers
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0372
AU Hansen-Bristow, K.
DT 1979
TI The instability of the conifer species within the forest-alpine tundra
 ecotone, Niwot Ridge, Colorado
SO Proceedings of the Second Conference on Scientific Research in the National
 Parks, San Francisco. Abstract
DE Abstract
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Conifers
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0374
AU Hansen-Bristow, K.J.
DT 1981
TI Environmental controls and physiological responses of the forest-alpine
 tundra ecotone, Front Range, Colorado
SO Association of American Geographers National Convention Abstracts, Los
 Angeles, 51-52
DE Abstract
; Ecology
; NASA - PY
; Niwot Ridge
; Conifers
; Altitude
; Climate - Discussion of
; Physiological
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0376
AU Hansen-Bristow, K.J.
; Ives, J.D.
DT 1984
TI Changes in the forest alpine tundra ecotone: Colorado Front Range
SO Physical Geography, 5:186-187
DE Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Conifers
; Altitude
; Climate - Discussion of
; Physiological
; Succession
; Tree
; Forest-Tundra Ecotone (Timberline)
; NWTLTER
AB None
$
CL 0375a
AU Hansen-Bristow, K.J.
DT 1985
TI Growth responses of lodgepole pine and quaking aspen to sewage effluent
 application
SO Proceedings of the Montana Academy of Science, (45):19-25
DE Ecology
; Management
; Mountain Research Station - Location
; Angiosperms
; Conifers
; Growth (Development)
; Fertilizers
; Pollution
AB None
$
CL 0373
AU Hansen-Bristow, K.J.
DT 1981
TI Environmental controls influencing the altitude and form of the
 forest-alpine tundra ecotone, Colorado Front Range
SO Ph.D. dissertation, University of Colorado, Boulder. 245 pp.
DE Dissertation
; Ecology
; NASA - PY
; Niwot Ridge
; Conifers
; Altitude
; Climate - Discussion of
; Physiological
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0375
AU Hansen-Bristow, K.J.
DT 1982
TI Environmental factors influencing growth within the forest-alpine tundra
 ecotone, Colorado Front Range
SO Association of American Geographers National Convention Abstracts, San
 Antonio, 80
DE Abstract
; Ecology
; NASA - PY
; Niwot Ridge
; Conifers
; Altitude
; Climate - Discussion of
; Physiological
; Tree
; Forest-Tundra Ecotone (Timberline)
; Growth (Development)
AB None
$
CL 0376b
AU Hansen-Bristow, K.J.
; Ives, J.D.
; Wilson, J.P.
DT 1988
TI Climatic variability and tree response within the forest-alpine tundra
 ecotone
SO Annals of the Association of American Geographers, 78(3):505-519
DE Journal
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Conifers
; Forest-Tundra Ecotone (Timberline)
; Forest Tundra Ecotone (Timberline)
; Climate - Discussion of
; Growth (Development)
; Stratigraphy
; NWTLTER
AB None
$
CL 0376a
AU Hansen-Bristow, K.J.
; Ives, J.D.
DT 1985
TI Composition, form, and distribution of the forest-alpine tundra ecotone,
 Indian Peaks, Colorado, USA
SO Erdkunde, 39:286-295
DE Ecology
; Long-Term Ecological Research Program
; NASA - PY
; Indian Peaks Region
; Conifers
; Angiosperms
; Altitude
; periglacial
; Snow
; Temperature
; Community
; Distribution
; Forest - Tundra Ecotone (Timberline)
; Morphological
; Tree
; NWTLTER
AB None
$
CL 0375b
AU Hansen-Bristow, K.J.
DT 1986
TI Influence of increasing elevation on growth characteristics at timberline
SO Canadian Journal of Botany, 64:2517-2523
DE Biology
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Conifers
; Altitude
; Climate - Discussion of
; Soils
; Temperature
; Forest - Tundra Ecotone (Timberline)
; Growth (Development)
; Phenological (Seasonal)
; NASA - PY
; Tree
; NWTLTER
AB None
$
CL 0377
AU Hara, Y.
; Thorn, C.E.
DT 1982
TI Preliminary quantitative study of alpine subnival boulder pavements,
 Colorado Front Range, U.S.A.
SO Arctic and Alpine Research, 13:361-367
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Snow
AB None
$
CL 0378
AU Harbor, J.M.
DT 1984
TI Terrestrial and lacustrine evidence for Holocene climatic/
2000
geomorphic change
 in the Blue Lake and Green Lakes Valleys of the Colorado Front Range
SO M.A. thesis, University of Colorado, Boulder. 205 pp.
DE Thesis
; Geomorphology
; Paleoecology
; Sedimentology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Lake
; Stream
; Periglacial
; Sediment
; NWTLTER
AB None
$
CL 0378a
AU Harbor, J.M.
DT 1985
TI Problems with the interpretation and comparison of Holocene terrestrial and
 lacustrine deposits: an example from the Colorado Front Range, USA
SO Zeitschrift fur Gletscherkunde und Glazialgeologie, 21:17-24
DE Geomorphology
; Climatology
; Sedimentology
; Long-Term Ecological Research Program
; Model
; Boulder Watershed and Rainbow Lakes
; Climate - Discussion of
; Dating - Radiocarbon and Other
; Lake
; Watershed
; NWTLTER
AB None
$
CL 0381
AU Harris, S.A.
DT 1968
TI Till fabrics and speed of movement of the Arapahoe Glacier, Colorado
SO The Professional Geographer, 20:195-198
DE Geomorphology
; Soil sciences
; Boulder Watershed and Rainbow Lakes
; Sediment
; Glacier
AB None
$
CL 1324
AU Hartz, A.A.
DT 1997
TI Simulation of carbon and nitrogen cycling in an alpine tundra system. 
SO M.S. thesis, University of Colorado, Boulder. 71 pp.
DE NWTLTER
; carbon
; nitrogen
AB None
$
CL1454
AU Hazen, J.H.
; Williams, M.W.
; Stover, B.
; Wireman, M.
DT 2002
TI Characterisation of Acid Mine Drainage using a Combination of Hydrometric, Chemical and Isotropic Analyses, Mary Murphy Mine, Colorado
SO Environmental Geochemistry and Health. v.24 pp 1-22
DE NWTLTER
; acid mine drainage
; hydrochemistry
; isotope hydrology
; zinc
AB None
$
CL 0383
AU Heffernan, M.W.
; Halfpenny, J.C.
DT 1984
TI Snow and plant community distribution in the alpine tundra, Front Range,
 Colorado
SO New Mexico Journal of Science, 24(1):48. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Snow
; Community
; Distribution
AB None
$
CL 0388
AU Henderson, J.
DT 1905
TI Extinct glaciers of Colorado
SO University of Colorado Studies, 3:39-44
DE Glaciology
; University of Colorado
; Indian Peaks Region
; Glacier
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0389
AU Henderson, J.
DT 1909
TI An annotated list of the birds of Boulder County, Colorado
SO University of Colorado Studies, 6:219-242
DE Fauna
; History
; Taxonomy & systematics
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Birds
; Distribution
AB None
$
CL 0387
AU Henderson, J.
DT 1904
TI Arapaho Glacier in 1903
SO Journal of Geology, 12:30-33
DE Glaciology
; Boulder Watershed and Rainbow Lakes
; Glacier
; History
AB None
$
CL 0391
AU Henderson, J.
DT 1921
TI Water works storage system
SO Report on the Boulder Watershed, available at University of Colorado
 Archives
DE History
; Hydrology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Water
AB None
$
CL 0390
AU Henderson, J.
DT 1910
TI Extinct and existing glaciers of Colorado
SO University of Colorado Studies, 8:33-76
DE Glaciology
; History
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Glacier
AB None
$
CL 0394
AU Hess, D.W.
DT 1959
TI Background gamma radiation of sites in the Rocky Mountain Front Range west
 of Boulder, Colorado
SO Attachment to Technical Progress Report to the United States Atomic Energy
 Commission, Contract No. AT(11-1)435. 14 pp. Mimeographed
DE Dissertation
; Radioecology
; Atomic Energy Commission
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0395
AU Hess, D.W.
DT 1959
TI Ecological studies of the growth of Ponderosa Pine on the East Slope of the
 Rocky Mountain Front Range in Boulder County, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 100 pp.
DE Dissertation
; Ecology
; University of Colorado
; A-1 Climate Station
; Conifers
; Climate - Discussion of
; Distribution
AB None
$
CL 1284
AU Hess, T.F.
; Schmidt, S.K.
DT 1995
TI Improved procedure for obtaining statistically valid parameter estimates
 from soil respiration data
SO Soil Biology and Biochemistry 27:19-28
DE NWTLTER
; carbon dioxide 
; microbial activity
; soil respiration
AB A method to obtain statistically reliable estimates of parameters of
 microbial activity in soil is presented. Most traditional methods of 
 measuring soil respiration involve the analysis of curves of CO2
 evolution obtained by accumulating discrete measurements of the CO2 over 
 time. Such analyses can be misleading because they do not provide a
 statistically valid way of estimating error and result in non-random,
 autocorrelated residuals. We have developed a method that uses non-linear
 regression analysis of discrete, non-accumulated data, thus alleviating 
 most of the problems associated with the analysis of cumulative data.
$
CL1461
AU Heuer, K.
; Tonnessen, K.A.
; Ingersoll, G.P.
DT 2000
TI Comparison of precipitation chemistry in the Central Rocky Mountains, Colorado, USA.
SO Atmospheric Environment 34:1713-1722
DE NWTLTER
AB None
$
CL 0396
AU Hibbard, K.A.
DT 1984
TI Tundra avian breeding phenology, Niwot Ridge, Colorado
SO New Mexico Journal of Science 24(1):47. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Birds
; Phenological (seasonal)
AB None
$
CL 0397
AU Hickman, T.J.
; Miller, D.L.
DT 1977
TI A report on the Greenback Cutthroat Trout Inventory program, July to
 October, 1977
SO Report prepared for the Colorado Division of Wildlife. 22 pp.
DE Data report
; Ecology
; Management
; Mountain Research Station - Location
; Fish
; Lake
; Stream
; Demography
AB None
$
CL 1483
AU Hobbie, J.E.
; Carpenter, S.R.
; Grimm, N.B.
; Gosz, J.R.
; Seastedt, T.R.
DT 2003
TI The US Long Term Ecological Research Program
SO BioScience v. 53 no. 1 pp. 21-32
DE LTER Network
; long-term ecological research
; LTER Accomplishments
; LTER History
; LTER Description
AB The 24 projects of the National Science Foundation s Long Term Ecological Research Network, whose sites range from the poles to the Tropics, from rain forests to tundras and deserts, and from offshore marine to estuarine and freshwater habitats, address fundamental and applied ecological issues that can be understood only through a long-term approach. Each project addresses different ecological questions; even the scale of research differs across sites. Projects in the network are linked by the requirement for some research at each site on five core areas, including primary production, decomposition, and trophic dynamics, and by cross-site comparisons, which are aided by the universally available databases.Many species and environmental variables are studied, and a wide range of synthetic results have been generated.$
CL 0399A
AU Hoffman, K.
; Caine, J.
; Caine, N.
DT 1985
TI Surface water quality in the Green Lakes Valley prior to peak flow 1985
SO University of Colorado Long-Term Ecological Research Data Report 85/7. 18 pp
DE Data Report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Map
; Watershed
AB None
$
CL 0399aa
AU Hoffman, K.L.
DT 1987
TI A geography of dissolved organic carbon in alpine snowmelt waters--the Green
 Lakes valleys of the Colorado Front Range.
SO M.A. thesis, University of Colorado Boulder, 165 pp.
DE thesis
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; precipitation
; snow
; water
; carbon
; nutrients
; NWTLTER
AB None
$
CL 0405
AU Holden, D.C.
TI A comparative study of two precipitation runoff models applied to a
 subalpine watershed
DT 1984
SO M.S. thesis, University of Colorado, Boulder. 65 pp.
DE Abstract
; Model
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Precipitation
; Watershed
; Lake
; Stream
; Water
; NWTLTER
AB None
$
CL 1225
AU Holland, E.A.
; Parton, W.J
2000
.
; Detling, J.K.
; Coppock, D.L.
DT 1992
TI Physiological responses of plant populations to herbivory and their
 consequences for ecosystem nutrient flow
SO American Naturalist 140: 685-706.
DE NWTLTER
; nutrient cycling
; carbon allocation
; nitrogen allocation
; herbivory
; CENTURY
; modeling
; nitrogen availability
AB We explored how responses of two populations variable in grazing tolerance
 provide feedbacks to nutrient supply by controlling carbon supply to soil
 heterotrophs. The study focused on differences in production and carbon and
 nitrogen allocation patterns between the two populations. The grazing-tolerant
 population, or on-colony population, is found on intensively grazed prairie
 dog colonies, and a grazing-intolerant population, the off-colony population,
 is found in uncolonized grasslands. Equations describing the production and
 allocation responses to defoliation for the two ecotypes described were
 incorporated into CENTURY, a nutrient-cycling simulation model. Simulations
 showed an increase in plant production that paralleled increases in net
 nitrogen mineralization. Production was greater with grazing and was
 maintained at higher grazing intensities for the on-colony than the off-colony
 population. Differences between the populations provided important controls
 over nitrogen losses. Feedbacks between plant responses to grazing and
 nitrogen cycling accounted for increased nitrogen availability with grazing.
 These feedbacks were more important determinants of ecosystem function than
 were fertilization effects of urine and feces deposition. The simulation
 results suggest that ecosystem function may be sensitive to physiological
 differences in population responses to periodic disturbances like herbivory.
$
CL 1359
AU Holland, E.A.
; Robertson, G.P.
; Greenberg, A.
; Groffman, P.M.
; Boone, R.D.
; Gosz, J.R.
DT 1999
TI Soil CO2, N2O, and CH4 exchange
SO In Robertson, G.P. et al. (eds.) Standard Soil Methods for Long-Term Ecological Research.
 Oxford Press. Pp. 185-201
DE NWTLTER
; soil
; nitrogen
; carbon
AB None
$
CL 0411a
AU Holtmeier, F.K.
DT 1987
TI Beobachtungen und Untersuchungen uber den Ausaperungsverlauf und einige
 Folgewirkungen in "ribbon-forests" an der oberen Waldgrenze in der Front
 Range, Colorado
SO Phytocoenologia, 15(3): 373-396
DE Ecology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Fungi
; Conifers
; Mammals
; Rodents
; Artiodactyls
; Wind
; Competition
; Disease
; Forest-Tundra Ecotone (Timberline)
; Seed
AB None
$
CL 0410a
AU Holtmeier, F.K.
DT 1979
TI Luftbild Arapaho - PaB
SO Die Erde, 110(2):97-106
DE article
; geography
; technique
; Mountain Research Station
; map
AB None
$
CL 0410
AU Holtmeier, F.K.
DT 1980
TI Influence of wind on tree-physiognomy at the upper timberline in the
 Colorado Front Range
SO In: Benecke, U. and Davis, M.R. (eds.), Mountain Environments and Subalpine
 Tree Growth. New Zealand Forest Service, Forest Research Institute Technical
 Paper 70:247-261
DE Ecology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Conifers
; Wind
; Physiographic
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0411b
AU Holtmeier, F.K.
DT 1987
TI Human impacts on high altitude forests and upper timberline with special
 reference to middle latitudes
SO In: Fujimori, T. and Kimura, M. (eds.), Proceedings, Human Impacts and
 Management of Mountain Forests. Ibaraki, Japan: Forestry and Forest Products
 Researach Institute, 9-20
DE Journal
; Management
; Mountain Research Station - Affiliation
; Conifers
; Angiosperms
; Disturbances
; Tree
; Forest Tundra Ecotone (Timberline)
; Latitude
AB None
$
CL 1333
AU Holtmeier, F.K.
; Broll, G.
DT 1992
TI The influence of tree islands and microtopography on pedoecological
 conditions in the forest-alpine tundra ecotone on Niwot Ridge, Colorado
 Front Range, U.S.A
SO Arctic and Alpine Research, 24:216-228
DE NWTLTER
; tree islands
; microtopography
; soil
; pedoecology
AB The extreme patchiness of plant communities and site conditions in the
 upper timberline ecotone is primarily controlled by the influence of 
 microtopography and scattered tree islands on windflow near the soil surface,
 which in turn affects the distribution pattern of the winter snow cover.
 Snow accumulates inside the tree islands, and large snowdrifts build up
 behind their leeward end. Both depth and duration of the snow cover as well
 as vegetation influence other site factors such as soil moisture and soil 
 temperature that are important to soil-forming processes. Moreover, deposition
 of alpine loess is enhanced by tree islands as revealed by the data on soil
 texture and Ca content. The study provides evidence for distinct differences
 in pedogenesis and soil properties on the windward, interior, and leeward 
 sides of tree islands. Such differences are evident in contents of organic
 matter and nutrients (N, P, K), C/N ratio, cation exchange capacity, and pH.
 Different soil types belonging to different great groups of Inceptisols
 developed as a result of specific conditions on windward, interior, and
 leeward sites. Under tree islands, pedogenesis is deeply influenced by a thick
 O horizon. Thus, initial podzolization was observed in some cases. Soil-
 forming processes gradually change due to downwind migration of wind-exposed 
 tree islands. Consequently, differences in pedoecological conditions on
 windward, interior, and leeward sites can only be explained in terms of
 microtopography and the long-term development of the migrating tree islands.
$
CL 0408a
AU Holtmeier, F.K.
DT 1985
TI Climatic stress influencing the physiognomy of trees at the polar and
 mountain timberline
SO Proceedings third IUFRO-workshop P1.07-00 1984. Eidgenossische Anstalt fur
 das Forstliche Versuchswesen, Bericht 270:31-40
DE article
; paleoecology
; ecology
; Mountain Research Station
; conifers
; climate - discussion of
; physiographic
; timberline
AB None
$
CL 0410d
AU Holtmeier, F.K.
DT 1986
TI Uber Bauminseln (Kollecktive) an der klimatischen Waldgrenze - unter
 besonderer Berucksichtigung von Beobachtungen in verschiedenen Hochgebirgen
 Nordamerikas
SO Wetter und Leben, 38:121-139
DE article
; paleoecology
; ecology
; Mountain Research Station
; Indian Peaks Region
; climate - discussion of
; conifers
AB None
$
CL 0410b
AU Holtmeier, F.K.
DT 1989
TI Oekologie und Geographie der oberen Waldgrenze
SO Ber.d.Reinh.Tuexen- Ges. 1, p.15-45, Goettingen.
DE article
; ecology
; geography
; Mountain Research Station
; conifers
; timberline
; tree
AB None
$
CL 0409
AU Holtmeier, F.K.
DT 1978
TI Die Bodennahen Winde in den Hochlagen der Indian Peaks Section (Colorado
 Front Range)
SO Munstersche Geographische Arbeiten, Paderborn, No. 3. 47 pp.
DE Climatology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Wind
; Distribution
; Conifers
AB None
$
CL 0411
AU Holtmeier, F.K.
DT 1981
TI What does the term "krummholz" really mean? Observations with special
 reference to the Alps and the Colorado Front Range
SO Mountain Research and Development, 1:253-260
DE Ecology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Wind
; Forest-Tundra Ecotone (Timberline)
; Tree
AB None
$
CL 0409a
AU Holtmeier, F.K.
DT 1981
TI Einige Besonderheiten des Krummholzgurtels in der Colorado Front Range
SO Wetter und Leben, 33:150-160
DE article
; paleoecology
; ecology
; Mountain Research Station
; conifers
; timberline
; tree
AB None
$
CL 0408b
AU Holtmeier, F.K.
DT 1987
TI Der Baumwuchs als klimaokologischer Faktor an der Hohen- und Polargrenze des
 Waldes
SO Munstersche Geographische Arbeiten, 27:145-151
DE article
; ecology
; Mountain Research Station
; Indian Peaks Region
; conifers
; climate - discussion of
; altitude
; timberline
; tree
AB None
$
CL 0410c
AU Holtmeier, F.K.
DT 1982
TI "Ribbon-forest" und "Hecken". Streifenartige Verbreitungsmuster des
 Baumwuchses an 
2000
der oberen Waldgrenze in den Rocky Mountains
SO Erdkunde, 36:142-153
DE article
; ecology
; Mountain Research Station
; Indian Peaks Region
; distribution
; growth
; timberline
; tree
AB None
$
CL 1366
AU Hood, E.
; Williams, M.
; Cline, D.
DT 1999
TI Sublimation from a seasonal snowpack at a continental, mid-latitude
 alpine site
SO Hydrological Processes 13:1781-1797
DE NWTLTER
; seasonal snow pack
; sublimation
; moisture transfers
AB Sublimation from the season snowpack was calculated using the aerodynamic
 profile method at Niwot Ridge in the Colorado Front Range. Past studies
 of sublimation from snow have been inconclusive in determining both the
 rate and timing of the transfer of water between the snowpack and the atmosphere,
 primarily because they relied on one-dimensional measurements of turbulent
 fluxes or short term data sets. We calculated latent head fluxes at ten
 minute intervals based on measurements of temperature, relative humidity and
 wind speed at heights of 0.5m, 1.0m, and 2.0m above the snowpack for nine months
 during the 1994-1995 snow season. The meteorological instruments were raised
 or lowered daily to maintain a constant height above the snow surface. At
 each ten minute time step, the latent heat fluxes were converted directly 
 into millimeters of sublimation or condensation. Total net sublimation for the
 snow season was 195mm of water equivalent, or 15% of maximum snow accumulation
 at the study site. The majority of this sublimation occurred during the snow
 accumulation season. Monthly losses to sublimation during the fall and winter
 ranged from 27 to 54mm of water equivalent. The snowmelt season from May
 through mid-July showed net condensation to the snowpack ranging from 5 to
 16mm of water equivalent. Sublimation was sometimes episodic in nature, but
 often showed a diurnal periodicity with higher rates of sublimation during 
 the day.
$
CL 1489
AU Hood, E.W.
; Williams, M.W.
; Caine, N.
DT 2003
TI Landscape Controls on Organic and Inorganic Nitrogen Leaching across an Alpine/Subalpine Ecotone, Green Lakes Valley, Colorado Front Range
SO Ecosystems v. 6 pp. 31-45
DE Green Lakes Valley
; NWTLTER
; nitrogen
; DON
; DOC
; surface water chemistry
; snow
; biogeochemistry
; Colorado Front Range
AB Here we report measurements of organic and inorganic nitrogen (N) fluxes from the high-elevation Green Lakes Valley catchment in the Colorado Front Range for two snowmelt seasons (1998 and 1999). Surface water and soil samples were collected along an elevational gradient extending from the lightly vegetated alpine to the forested subalpine to assess how changes in land cover and basin area affect yields and concentrations of ammonium-N (NH4-N), nitrate-N (NO3-N), dissolved organic N (DON), and particulate organic N (PON). Streamwater yields of NO3-N decreased downstream from 4.3 kg ha(-1) in the alpine to 0.75 kg ha(-1) at treeline, while yields of DON were much less variable (0.40-0.34 kg ha(-1)). Yields of NH4-N and PON were low and showed little variation with basin area. NO3-N accounted for 40%-90% of total N along the sample transect and was the dominant form of N at all but the lowest elevation site. Concentrations of DON ranged from approximately 10% of total N in the alpine to 45% in the subalpine. For all sites, volume-weighted mean concentrations of total dissolved nitrogen (TDN) were significantly related to the DIN:DON ratio (R-2 = 0.81, P < 0.001) Concentrations of NO3-N were significantly higher at forested sites that received streamflow from the lightly vegetated alpine reaches of the catchment than in a control catchment that was entirely subalpine forest, suggesting that the alpine may subsidize downstream forested systems with inorganic N. KCl-extractable inorganic N and microbial biomass N showed no relationship to changes in soil properties and vegetative cover moving downstream in catchment. in contrast, soil carbon-nitrogen (C:N) ratios increased with increasing vegetative cover in catchment and were significantly higher in the subalpine compared to the alpine (P < 0.0001) Soil C:N ratios along the sample transect explained 78% of the variation in dissolved organic carbon (DOC) concentrations and 70% of the variation in DON concentrations. These findings suggest that DON is an important vector for N loss in high-elevation ecosystems and that streamwater losses of DON are at least partially dependent on catchment soil organic matter stoichiometry.
$
CL 1505
AU Hood, E.W.
; McKnight, D.
; Williams, M.W.
DT 2003
TI Sources and chemical character of dissolved organic carbon (DOC) across an alpine/subalpine ecotone, Green Lakes Valley, Colorado Front Range, USA
SO Water Resources Research v. 39 no. 1188 
DE NWTLTER
; DOC
; biogeochemistry
; snowmelt
; chemical fractionation
; fluorescence spectroscopy
AB We investigated how the source and chemical character of aquatic dissolved organic carbon (DOC) change over the course of the runoff season (May-November, 1999) in Green Lakes Valley, a high-elevation ecosystem in the Front Range of the Colorado Rocky Mountains. Samples were collected on North Boulder Creek from four sites across an alpine/subalpine ecotone in order to understand how the transition from the lightly vegetated alpine to the forested reaches of the catchment influences aquatic DOC. Concentrations of DOC at the four sites peaked between 2.6 and 8.9 mg C L-1 on the ascending limb of the snowmelt hydrograph, with the higher concentrations at the two subalpine sites. Seasonally, the chemical fractionation of DOC showed that there was a large range (29-72%) in the fulvic acid content of DOC at the four sites, with the highest fulvic acid percentages on the ascending limb of the hydrograph. Yields of DOC at the two gauged sites ranged from 10 to 11 kg ha(-1) over the season with between 45 and 50% of the yield occurring as fulvic acid DOC and the remainder as nonhumic material. The fluorescence properties of DOC from all four sites indicated that during peak runoff, DOC was derived primarily from terrestrial precursor material. However, seasonal changes in the fluorescence properties of fulvic acids at the highest elevation sites suggest that DOC derived from algal and microbial biomass in the lakes is a more important source of DOC above tree line during late summer and fall. We hypothesize that much of the autochthonous DOC production is a result of algal growth in alpine lakes. Further, comparison to a forested control catchment suggests that processes in the alpine reach of the catchment may alter both the amount and chemistry of DOC incident to the downstream subalpine aquatic system.$
CL 1507
AU Hood, E.W.
; Williams, M.W.
DT 2001
TI Seasonal changes in the character and nitrogen content of dissolved organic material in an alpine/subalpine headwater catchment
SO The Scientific World v. 1
DE NWTLTER
AB None
$
CL 1481
AU Hood, R.W.
; Williams, M.W.
; Caine, N.
DT 2002
TI Yields of dissolved organic C, N, and P, from three high-elevation catchments, colorado front range, U.S.A.
SO Water, Air, and Soil Pollution: Focus v. 2 pp. 165-180
DE NWTLTER
; alpine watershed
; Colorado Front Range
; DOC
; DOM
; DON
; DOP
; surface waters
; yields
AB Ecosystem dynamics in high-elevation watersheds are extremely sensitive to changes in chemical, energy, and water fluxes.  Here we report infomration on yields of dissolved organic C, N, and P for the 1999 snowmelt runoff season from three high elevation catchments in the Colorado Front Range, USA: Green Lake 4 (GL4) and Albion townsite (ALB) on North Boulder Creek and Saddle Stream (SS), a tributary catchment dominated by alpine tundra.  Dissolved organic carbon (DOC) concentration ranged from below detection limits to 0.28 mg N L-1 and were again highest at the tundra-dominated site. Dissolved organic phosphorus (DOP)ntrations were at or near detection limits throughout the season in all three catchments indicating a strong terrestrial retention of P.  Only DOC showed a significant relationship to discharge.  yields of DOC in the three cat
2000
chments ranged from 10.6 to 11.8 kg C ha-1 while yields of DON and DOP ranged from 0.32 to 0.41 and 0.02 to 0.08 kg ha -1, respectively.  The relatively high yield of organic N and P relative to C from the highest elevation site (GL4) was somewhat surprising and points to either;(1) as source of dissolved organic material(DOM) in the upper reaches of the catchment that is enriched in these nutrients of (2) the selective uptake and processing of organic N and P downstream of the sampling site.  Additionally, seasonal changes in the relative importance of DOM precursor materials appear to result in changes in the N content of DOM at both the GL4 and ALB sites.
$
CL 0418
AU Hubbard, J.D.
DT 1978
TI Breeding biology and reproductive energetics of Mt. White-Crowned sparrows
 in Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 311 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Birds
; Climate - Data Included
; Bioenergetics
; Reproduction
AB None
$
CL 0419
AU Huebert, B.J.
; Fehsenfeld, F.C.
; Norton, R.B.
; Albritton, D.
DT 1983
TI The scavenging of nitric acid vapor by snow
SO In: Pruppacher et al. (eds.), Precipitation Scavenging, Dry Deposition, and
 Resuspension. New York: Elsevier, 293-302
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Acid Deposition
; Precipitation
; Snow
; Nitrogen
AB None
$
CL 0421
AU Huebert, B.J.
; Norton, R.B.
; Bollinger, M.J.
; Parrish, D.D.
; Hahn, C.
; Bush, Y.A.
; Murphy, P.C.
; Fehsenfeld, F.C.
; Albritton, D.L.
DT 1983
TI Gas phase and precipitation acidities in the Colorado mountains
SO In: Herrman, R. and Johnson, A.I. (eds.), Acid Rain, A Water Resources Issue
 for the 80's. Bethesda, MD: American Water Resources Association, 17-23
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Acid Deposition
; Precipitation
; Wind
AB None
$
CL 0420
AU Huebert, B.J.
; Norton, R.B.
; Bollinger, M.J.
; Parrish, D.D.
; Hahn, C.
; Bush, Y.A.
; Murphy, P.C.
; Fehsenfeld, F.C.
; Albritton, D.L.
DT 1982
TI Gas phase and precipitation acidities in the Colorado mountains
SO International Symposium on Hydrometeorology, June 1982. American Water
 Resources Association, 17-23
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Acid Deposition
; Precipitation
; Wind
AB None
$
CL 0422
AU Huebert, B.J.
; Norton, R.B.
; Bollinger, M.J.
; Parrish, D.D.
; Murphy, P.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
DT 1982
TI HNO3 and NO3- particulates measured at a remote rural site. Proceedings of
 Second Symposium on the Composition of the Nonurban Troposphere, May 25-28,
 1982; Williamsburg, Va.
SO Boston: American Meteorological Society, 163-165
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Acid Deposition
; Precipitation
; Nitrogen
AB None
$
CL 1296
AU Humphries, H.C.
; Coffin, D.P.
; Lauenroth, W.K.
DT 1996
TI An individual-based model of apline plant distributions
SO Ecological Modelling 84:99-126
DE NWTLTER
; Alpine grasslands
; Individual-based models
; Species distribution
; Kobresia myosuroides
AB Our objective was to evaluate the relationships between alpine plant
 distributions and environmental conditions in order to predict the spatial
 distribution of major alpine plant communities found along the Front Range of
 the Rocky Mountains in the western U.S. Our approach was to modify the
 individual plant-based STEPPE model to simulate plant responses for three
 alpine communities found on Niwot Ridge, Colorado, USA:  fellfield, dry meadow,
 and wet meadow. We used the alpine model to evaluate the relationship between
 alpine plants and their environment both for conditions typical of each
 community and for conditions along a gradient that includes transitions between
 communities.  We also analyzed model behavior using sensitivity analysis, and
 tested the ability of the model to simulate alpine plant community dynamics
 using verification and validation procedures.  The individual plant-based
 alpine model tracks the recruitment, growth, and mortality of individual plants
 on a small plot (0.09 m2)through time at an annual time step. Eighteen species
 with the greatest abundance in fellfield, dry meadow, and moist meadow
 communities, and representing a range of life history characteristics and
 environmental responses are included. Environmental factors in the model are
 average daily maximum temperature during the growing season, growing season
 soil water availability, snow depth, and disturbances. Recruitment and
 mortality by species have elements of stochasticity whereas growth of an
 individual plant is determined by resource availability and abundance of
 plants.  Patterns of species composition and aboveground biomass simulated by
 the model were in general agreement with observations from the three alpine
 communities. Simulated fellfield communities were dominated by cushion plants,
 dry meadow communities by Kobresia myosuroides and Acomastylis rossii, and
 moist meadow communities were dominated by Acomastylis rossii and Deschampsia
 caespitosa. Shifts in species composition and dominance were observed along the
 two environmental gradients investigated (soil water availability and snow
 depth). Cushion plants dominated areas of low soil water and snow depth
 representative of fellfield conditions. A shift to graminoid-dominated
 vegetation, in particular K. myosuroides, occurred over a narrow range of soil
 water conditions and snow depth.  At high soil water and snow depth, this
 species decreased in biomass as a result of snow-induced mortality, and a forb
 and graminoid species (A. rossii and D. caespitosa, respectively) dominated the
 vegetation. The transition from dry meadow to moist meadow was more gradual
 than the transition from fellfield to dry meadow.  
$
CL 1255
AU Humphries, H.C.
DT 1993
TI An individual-based approach to alpine plant distributions
SO Ph.D. dissertation, Colorado State University, Fort Collins. 215 pp
DE NWTLTER
; Niwot Ridge
; modeling
; plant distribution
AB None
$
CL 1314
AU Ingersoll, R.C.
; Seastedt, T.R.
; Hartman, M.A.
DT 1997
TI A model information management system for ecological research
SO BioScience 47(5):310-316
DE NWTLTER
; information management
; data management
; metadata
; data documentation
; data archiving
AB None
$
CL 0424
AU Ingraham, K.P.
; Halfpenny, J.C.
; Southwick, C.H.
; Golian, S.C.
; Hause, H.L.
DT 1984
TI Ecology of small mammal herbivores from the Colorado alpine tundra
SO New Mexico Journal of Science 24(1):46-47. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Mammals
; Demography
; Biomass
; Reproduction
AB None
$
CL 1389
AU Inyan, B.
; Williams, M.W    
DT 2001
TI Protecting headwater catchments from future degradation, San Miguel River, CO
SO Mountain Research and Development 21(1):71-78
DE None
AB None
$
CL 1383
AU Inyan, B.J.
; Williams, M.W. 
; Tonnessen, K.
; Turk, J.T.
; Campbell, D.H.
DT 1998
TI Seasonal inorganic nitrogen release in alpine lakes on the Colorado 
   western slope
SO Physical Geography 19(5):406-420
DE NWTLTER
; episodic acidification
; nitrogen deposition
; nitrate
; alpine ecosystems
; lanscape type
; Rocky Mountains
AB In the Rocky Mountains, the association of increase in acidic 
 deposition with increased atmospheric loading of sulfate and direct 
 changes in surface water chemistry has been well established.  The 
 importance, though of increased nitrogen (N) deposition in the episodic 
 acidification of alpine lakes and N saturation in alpine ecosystems is 
 only beginning to be documented.  In alpine areas of the Colorado Front 
 Range, modest loadings of N in deposition have been associated with leakage 
 of N to surface waters.  On the Colorado western slope, however, no leakage 
 of N to surface waters has be
2000
en reported.  A 1995 study that included early 
 season under-ice water samples that were not available in earlier studies 
 showed that there is, in fact, N leakage to surface waters in some western 
 slope basins.  Under-ice nitrate (NO-3) concentrations were as high as 10.5 
 micoeq L-1, and only decreased to detection limits in September.  Landscape 
 type appears to be important in leakage of N to surface waters, which is 
 associated with basins having steep slopes, thin soils, and large amounts 
 of exposed bedrock.  NO-3 leakage compounds the exixting sensitivity to episodic 
 acidification from low acid neutralizing capacity (ANC), which is less than 40 
 micoeq L-1 in those basins.
$
CL 0425
AU Irwin, R.L.
DT 1982
TI The influence of soil nitrogen, phosphorus, and potassium on the germination
 and establishment of alpine plants
SO Master of B.S. thesis, University of Colorado, Boulder. 40 pp.
DE Thesis
; Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Chemistry
; Community
; Nutrients
; Saddle, Niwot Ridge
AB None
$
CL 0426
AU Isard, S.A.
DT 1983
TI Estimating potential direct insolation to alpine terrain
SO Arctic and Alpine Research, 15:77-89
DE Climatology
; Long-Term Ecological Research Program
; Niwot Ridge
; Insolation
AB None
$
CL 0428a
AU Isard, S.A.
; Belding, M.J.
DT 1989
TI Evapotranspiration from the alpine tundra of Colorado, USA
SO Arctic and Alpine Research, 21(1):71-82
DE Journal
; Climatology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Climate - Discussion of
; Precipitation
; Wind
; Temperature
; Evapotranspiration
; NWTLTER
AB None
$
CL 0428
AU Isard, S.A.
DT 1986
TI Factors influencing soil moisture and plant community distribution on Niwot
 Ridge, Front Range, Colorado, U.S.A.
SO Arctic and Alpine Research, 18:83-96
DE Community
; Distribution
; Evapotranspiration
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Precipitation
; Snow
; Soil
; NWTLTER
AB None
$
CL 0427
AU Isard, S.A.
TI Factors controlling soil moisture and evapotranspiration within alpine
 vegetation communities: Niwot Ridge, Colorado Front Range
DT 1984
SO Ph.D. dissertation, Indiana University, Bloomington. 97 pp.
DE Dissertation
; Climatology
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Soil
; Water
; Community
; Evapotranspiration
; Precipitation
; Snow
; NWTLTER
AB None
$
CL 0428aa
AU Isard, S.A.
DT 1989
TI Topoclimatic controls in an alpine fellfield and their ecological
 significance
SO Physical Geography 10:13-31
DE article
; climatology
; Long-Term Ecological Research Program
; Niwot Ridge
; Tracheophytes
; climate - discussion of
; temperature
; precipitation
; wind
; community
; NWTLTER
AB None
$
CL 0425a
AU Isard, S.A.
DT 1987
TI The effect of slope-aspect on turbulent transfer in an alpine fellfield,
 Niwot Ridge, Front Range, Colorado
SO Physical Geography, 8:133-147
DE article
; model
; climatology
; Mountain Research Station
; Saddle
; Niwot Ridge
; wind
AB None
$
CL 0426a
AU Isard, S.A.
DT 1986
TI Evaluation of models for predicting insolation on slopes within the Colorado
 alpine tundra
SO Solar Energy, 36:559-564
DE article
; model
; climatology
; Mountain Research Station
; Saddle
; Niwot Ridge
; insolation
; energy budget
AB None
$      
CL 1427
AU Isard, S.A.
DT 1986
TI Factors influencing soil moisture and plant community distribution on Niwot Ridge, Front Range, Colorado, U.S.A  
SO Arctic and Alpine Research 18(1): 83-96
DE None
AB Slope-aspect influenced evapotranspiration and soil desiccation in the Colorado alpine tundra via control over radiation and wind speed. South- and east-facing sites upon a fellfield knoll received 18 and 14% more net radiation than the north-facing slope on a clear sky and more typical summer days, respectively. West-facing slopes experienced moderate radiation loads but highest wind speeds. Water loss during two drying sequences for east-, west-, and north-facing slopes was 80,80, and 60%, respectively, of evapotranspiration from the south-facing slope. Consequently, soil at the south-facing site dried faster than soil on other slopes of the knoll. Dryas octopetala prefers more moist northern slopes on Niwot Ridge, illustrating the importance of topoclimatic controls over soil moisture to vegetation distribution in the fellfield. Water realtions during the growing season influence vegetation distribution within topographic depressions on Niwot Ridge. Where meltwater is supplied throughout the growing season wet meadow and moist shrub tundra occur. Evapotranspiration from the wet meadow was 1.5 times greater than from other communities in the Saddle area during a drying period. Contrasts in snow cover depth between windward and leeward slopes is an important location factor for dry fellfield, dry meadow, moist meadow, and snowbed vegetation.          
$
CL 0437
AU Ives, J.D.
DT 1980
TI Introduction: A description of the Front Range
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 1-8
DE Overview
; Geoecology
; Institute of Arctic and Alpine Research
AB None
$
CL 0432
AU Ives, J.D.
DT 1974
TI Permafrost
SO In: Ives, J.D. and Barry, R.G. (eds.), Arctic and Alpine Environments.
 London: Methuen, 159-194
DE Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Permafrost
; Climate - Discussion of
AB None
$
CL 0447
AU Ives, J.D.
; Hansen-Bristow, K.J.
DT 1983
TI Stability and instability of natural and modified upper timberline
 landscapes in the Colorado Rocky Mountains, U.S.A.
SO Mountain Research and Development, 3:149-155
DE Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Climate - Discussion of
; Disturbances
; Tree
; Forest-Tundra Ecotone (Timberline)
; NWTLTER
AB None
$
CL 0433
AU Ives, J.D.
DT 1978
TI Remarks on the stability of timberline
SO In: Troll, C. and Lauer, W. (eds.), Geoecological Relations Between the
 Southern Temperate Zone and the Tropical High Mountains. Wiesbaden: Franz
 Steiner Verlag, 313-317. Reprinted in: Ives, J.D. (ed.), 1980, Geoecology of
 the Colorado Front Range. Boulder: Westview Press, 351-358
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Conifers
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0434
AU Ives, J.D.
DT 1980
TI The development of a Front Range Mountain Research Station
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press, xv-xxv
DE Overview
; Management
; Institute of Arctic and Alpine Research
; Mountain Research Station - Location
; History
AB None
$
CL 0431
AU Ives, J.D.
DT 1974
TI The impact of man as a biped
SO In: Ives, J.D. and Barry, R.G. (eds.), Arctic and Alpine Environments.
 London: Methuen, 921-924
DE Management
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Rocky Mountain National Park - Location
; Disturbances
AB None
$
CL 0429
AU Ives, J.D.
DT 1973
TI Permafrost and its relationship to other environmental parameters in a
 midlatitude, high-altitude setting, Front Range, Colorado Rocky Mountains
SO Permafrost: The North American Contribution to the Second International
 Conference, Washington, D.C.: National Academy of Science, 121-125. Reprinted
 in: Ives, J.D. (ed.) 1980, Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 316-325
DE Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Altitude
; Permafrost
; Climate - Discussion of
; Latitude
AB None
$
CL 0436
AU Ives, J.D.
DT 1980
TI Geomorphology: overview
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 84-90
DE Overview
; Geomorphology
AB None
$
CL 0449
AU Ives, J.D.
; Webber, P.J.
DT 1980
TI Plant ecology: overview
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press. 326-338
DE Glaciology
; Overview
; Ecology
; Institute of Arctic and Alpine
2000
 Research
; Plant
AB None
$
CL 0445
AU Ives, J.D.
; Fahey, B.D.
DT 1971
TI Permafrost occurrence in the Front Range, Colorado Rocky Mountains, U.S.A.
SO Journal of Glaciology, 10(58):105-111
DE Geomorphology
; Institute of Arctic and Alpine Research
; Indian Peaks Region
; Niwot Ridge
; Permafrost
; Altitude
AB None
$
CL 0438
AU Ives, J.D.
DT 1980
TI Preface
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range: Boulder:
 Westview Press, xv-xxv
DE Overview
; Geoecology
; Institute of Arctic and Alpine Research
; History
; Mountain Research Station - Location
AB None
$
CL 0435
AU Ives, J.D., (ed.)
DT 1980
TI Geoecology of the Colorado Front Range: A study of alpine and subalpine
 environments
SO Boulder: Westview Press. 484 pp.
DE Overview
; Climatology
; Ecology
; Geoecology
; Geology
AB None
$
CL 0469
AU Ives, R.L.
DT 1951
TI Modern glaciers of the Arapaho Massif
SO Scientific Monthly, 73:25-36
DE Glaciology
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Glacier
AB None
$
CL 0450
AU Ives, R.L.
DT 1935
TI Some past and present glaciers of Colorado
SO Rocks and Minerals, 10:129-136
DE Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0451
AU Ives, R.L.
DT 1936
TI Are our glaciers disappearing?
SO Trail and Timberline, 207:3-5
DE Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0466
AU Ives, R.L.
DT 1942
TI Early human occupation of the Colorado headwaters region - an archeological
 reconnaissance
SO Geographical Review, 32:448-462
DE Archaeology
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
AB None
$
CL 0457
AU Ives, R.L.
DT 1939
TI Glacier Measurements
SO Report International Commission on Snow, p. 5
DE Glaciology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0453
AU Ives, R.L.
DT 1937
TI The Arapahoe Glacier
SO Nature Magazine, 29:166-169
DE Glaciology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0459
AU Ives, R.L.
DT 1940
TI Mountain glaciers of long ago
SO Trail and Timberline, 258:87-92
DE Glaciology
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Glacier
AB None
$
CL 0464
AU Ives, R.L.
DT 1941
TI Tundra ponds
SO Journal of Geomorphology, 4:285-296
DE Geomorphology
; Boulder Watershed and Rainbow Lakes
; Lake
; Frost
; Succession
; Artiodactyls
AB None
$
CL 0470
AU Ives, R.L.
DT 1953
TI Later Pleistocene glaciation in the Silver Lake Valley, Colorado
SO Geographical Review, 63:229-253
DE glaciology
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0460
AU Ives, R.L.
DT 1940
TI Rock glaciers in the Colorado Front Range
SO Geological Society of America Bulletin, 51:1271-1294
DE Geomorphology
; Boulder Watershed and Rainbow Lakes
; Glacier
; Climate - Discussion of
AB None
$
CL 0458
AU Ives, R.L.
DT 1940
TI Glaciers in the Colorado Front Range
SO Bulletin Geological Society of America, 51:1271-1264
DE Glaciology
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Glacier
AB None
$
CL 1254
AU Jaeger, C.H.
DT 1993
TI Plant and soil nitrogen interactions in the alpine
SO Ph.D. dissertation, University of Colorado, Boulder. 98 pp
DE NWTLTER
; Niwot Ridge
; nutrient cycling
; plant/soil interactions
; nitrogen
AB None
$
CL 1400  
AU Jaeger, C.H.
; Monson, R.K.
; Fisk, M.
; Schmidt, S.
DT 1999
TI Seasonal partitioning of nitrogen by plants and soil microorganisms in an   alpine ecosystem
SO Ecology 80(6): 1883-1891.
DE None
AB None
$
CL 1226
AU Jaeger, C.H.
; Monson, R.K.
DT 1992
TI Adaptive significance of nitrogen storage in Bistorta bistortoides, an
 alpine herb
SO Oecologia 92: 578-585
DE NWTLTER
; Bistorta bistortoides
; nitrogen
; storage
; allocation
; growth
; Niwot Ridge Saddle
AB Studies were conducted to examine the importance of nitrogen storage to
 seasonal aboveground growth in the alpine herb Bistorta bistortoides. Stored
 reserves accounted for 60% of the total nitrogen allocated to the shoot during
 the growing season. The stored nitrogen was equally partitioned between the
 preformed buds of the shoot and the roots/rhizome. Reliance on stored N was
 similar in populations of a 105-day growing season site and of a 75-day
 growing season site. Contrary to our initial hypothesis, stored nitrogen
 reserves were not used to extend the growing season of this species into the
 late-spring when soils are still cold, and saturated with snow-melt water. The
 time at which stored nitrogen was used to initiate shoot growth coincided with
 the time of root initiation, rapid soil warming, and near maximum soil
 concentrations of NO3- and NH4+. Thus, nitrogen demand and soil nitrogen
 supply were both high at the same time. The importance of nitrogen storage in
 this species appeared to be in satisfying the high demand of simultaneous
 vegetative and reproductive growth during the early-growing season after soils
 thawed. The initiation of rapid leaf and inflorescence growth occurred in
 mid-June in both sites. The maximum pool size of shoot nitrogen (maximum
 nitrogen demand) occurred only 12 days later in the long season site, and 28
 days later in the short season site. The early-season utilization of nitrogen
 stores allows plants of this species to initiate reproductive allocation at
 the same time vegetative tissues are exhibiting maximal growth rates. By
 releasing vegetative and reproductive growth from competition for nitrogen,
 seeds could mature early in the alpine growing season, before the frost
 probability sharply increases in mid-August.
$
CL 0724e
AU James, E.D.
; Brendecke, C.M.
DT 1985
TI The redistribution and sublimation loss of the snowpack in the alpine
 watershed
SO In:  Proceedings of the 53rd Annual Western Snow Conference pp. 148-151
DE Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Watershed
; NWTLTER
AB None
$
CL 1568
AU Janke, J.R. 
DT 2005
TI The occurrence of alpine permafrost in the Front Range of Colorado
SO Geomorphology vol. 67 pp. 375-389
DE Alpine Permafrost
; GIS applications
; Front Range
; Rock Glaciers
AB Permafrost distribution, or ground that remains frozen for at least 2 years, has been modeled using a combination of Geographic Information System (GIS) techniques, Digital Elevation Model (DEM) variables, and land cover in alpine regions of the world. In the Front Range, however, no such empirical models have been developed, and field data are restricted in spatial extent, but rock glaciers are in abundance. Here, I present a probabilistic logistic regression model that is based on topoclimatic information (elevation and aspect) for rock glaciers derived from U.S. Geological Survey (USGS) 10-m DEMs. Classes of land cover, obtained from an Enhanced Thematic Mapper Plus (ETM+) image classification, were assigned weights and were then multiplied by the regression results to refine estimates. The effectiveness of the model was evaluated by comparing mean probability scores with rock glacier activity categories, Mean Annual Air Temperature (MAAT) from climatic stations on Niwot Ridge, and Bottom Temperature of winter Snow (BTS) measurements, while a Monte Carlo simulation was used to detect uncertainty associated with the original DEM. Permafrost scores N50% covered about 8.9% (242 km 2 ) of the study area (2722 km 2 ) with the highest scores clustered around Longs and Rowe Peaks. Permafrost locations showed a strong correlation with rock glacier activity classes, the   1.0 8C MAAT isotherm, and BTS measurements less than   3.0 8C. The uncertainty analysis revealed that slight global differences exist between the original and error prone DEM; however, local variations in aspect caused the most uncertainty. These results indicate that the model accurately represents regional distribution of permafrost. Therefore, topoclimatic information from rock glaciers and land cover, when combined wit
2000
h an uncertainty analysis, can effectively be used to map the occurrence of Front Range permafrost, providing an imperative tool for cartographers, planners, and geocryologists.  $
CL 0474
AU Janke, R.A.
DT 1970
TI Transpiration resistance in Vaccinium myrtillu
SO American Journal of Botany, 57:1051-1054
DE Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Bioenergetics
; Evapotranspiration
; Productivity
AB None
$
CL 0473
AU Janke, R.A.
DT 1968
TI The ecology of Vaccinium myrtillus using concepts of productivity, energy
 exchange, and transpiration resistance
SO Ph.D. dissertation, University of Colorado, Boulder. 109 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Bioenergetics
; Evapotranspiration
; Productivity
AB None
$
CL 0476
AU Johnson, A.W.
DT 1956
TI Ecology of subalpine forest communities in the Silver Lakes Valley of the
 Front Range in Colorado
SO Ph.D. dissertation, University of Colorado. 121 pp.
DE Dissertation
; Ecology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Conifers
; Climate - Discussion of
; Climate - Data Included
; Fire
; Soil
AB None
$
CL 0475
AU Johnson, A.W.
DT 1951
TI Indications of altitudinal distribution in some mouse fleas of Boulder
 County, Colorado
SO M.S. thesis, University of Colorado, Boulder. 55 pp.
DE Thesis
; Ecology
; University of Colorado
; Mountain Research Station - Location
; Insects
; Rodents
; Altitude
; Distribution
AB None
$
CL 1270
AU Johnson, C.E.
; Litaor, I.M.
; Billett, M.F.
; Bricker, O.P.
DT 1994
TI Chemical weathering in small catchments: Climatic and anthropogenic
 influences.
SO Pp. 323-341 In: Moldan, B., and J. Cerny (eds.). Scope 51: 
 Biogeochemistry of Small Catchments: A Tool for Environmental Research.
 New York: John Wiley & Sons. 419 pp.
DE NWTLTER
; Green Lakes Valley
; weathering
; biogeochemistry
; buffering
; acidity
; nutrient cycling
AB Chemical denudation through weathering of soil and rock minerals
 is an important component of the biogeochemistry of ecosystems. In
 virtually all environments, weathering results in the neutralization
 of hydrogen ion (H+) and the production of soluble basic cations 
 (CB: Ca, Mg, K, and Na), aluminum and silica (H4SiO4). Thus, it has
 been recognized that weathering plays an important role in the 
 buffering of surface waters and the supply of nutrient cations (Ca,
 Mg, and K) to the soil. Chemical weathering rates are influenced by
 many edaphic factors. The importance of the mineralogy and 
 geochemistry of the rock being weathered is obvious. Climate also
 has a major influence. Under pristine conditions, weathering rates
 should be highest in warm, moist climates. Weathering is also a 
 major sink for H+ in most natural systems (the rare exception being
 those underlain by sulphide-rich parent material). Thus, 
 environments characterized by high fluxes of acidity are expected
 to have higher rates of chemical weathering. Since fossil fuel 
 combustion and other human activities produce acidity, it is 
 reasonable to hypothesize that weathering rates are greater in
 heavily impacted areas. Our goals in this chapter are to summarize
 what is known from catchment studies about chemical weathering 
 rates in different climatic regimes and the impacts of human
 activities on weathering rates. Chemical weathering is one of 
 several processes which contribute to the chemical denudation of
 catchments. However, measured rates of chemical denudation can be
 used to estimate chemical weathering rates if the rates of biomass
 accumulation and changes in soil exchangeable cation pools are
 either measured or assumed to be negligible. Some of the catchment
 studies cited in this chapter included direct measurement of these
 changes. In many of the studies, biomass and soil changes were
 assumed to be negligible by the original investigators.
$
CL 0477
AU Johnson, D.
DT 1984
TI Acid rains on the Rockies
SO Summit (University of Colorado) January: 17-20
DE Atmospheric sciences
; University of Colorado
; Niwot Ridge
; Acid Deposition
; Precipitation
AB None
$
CL 0481
AU Johnson, D.A.
; Caldwell, M.M.
DT 1975
TI Gas exchange of four arctic and alpine tundra plant species in relation to
 atmospheric and soil moisture stress
SO Oecologia, 21:93-108
DE ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Carbon Dioxide
; Soil
; Water
; Physiological
AB None
$
CL 0480
AU Johnson, D.A.
; Caldwell, M.M.
DT 1974
TI Field measurements of photosynthesis and leaf growth rates of three alpine
 plant species
SO Arctic and Alpine Research, 6:245-251. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 396-402
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Saddle, Niwot Ridge
; Angiosperms
; Growth (Development)
; Photosynthesis
AB None
$
CL 0482
AU Johnson, D.A.
; Caldwell, M.M.
DT 1976
TI Water potential components, stomatal function, and liquid phase water
 transport resistances of four arctic and alpine species in relation to
 moisture stress
SO Physiologia Planta, 36:271-278
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Water
; Evapotranspiration
; Physiological
AB None
$
CL 0478
AU Johnson, D.A.
DT 1973
TI Field measurements of photosynthesis and leaf growth rates of three alpine
 plant species
SO M.S. thesis, Utah State University, Logan.  30 pp.
DE Thesis
; Ecology
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Growth (Development)
; Photosynthesis
AB None
$
CL 0483
AU Johnson, D.A.
; Caldwell, M.M.
; Tieszen, L.L.
DT 1973
TI Photosynthesis in relation to leaf water potential in three alpine plant
 species
SO In: Bliss, L.C. and Wielgolaski, F.E. (eds.), Proceedings of the Conference
 on Primary Production and Production Processes, Tundra Biome. Dublin, Ireland,
 April 1973. Stockholm: IBP Tundra Biome Steering Committee, 205-210
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Water
; Photosynthesis
; Physiological
AB None
$
CL 0479
AU Johnson, D.A. (ed.)
DT 1979
TI Special Management Needs of Alpine Ecosystems
SO Range Science Series, 5. 100 pp.
DE Overview
; Ecology
; Management
; Niwot Ridge
; Plant
; Animals
AB None
$
CL 0484
AU Johnson, J.B.
DT 1979
TI Mass balance and aspects of the glacial environment, Front Range, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder.  287 pp. Summarized in:
 Ives, J.D. (ed.), 1980: Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 209-213
DE Dissertation
; Glaciology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Snow
; Glacier
AB None
$
CL 0486
AU Johnston, M.A.
DT 1966
TI The ecological physiology of three Colorado varieties of Hymenoxys acaulis
 (Pursh) Parker
SO Ph.D. dissertation, University of Colorado, Boulder. 209 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Rollins Pass and Tolland
; Angiosperms
; Climate - Discussion of
; Physiological
AB None
$
CL 0487
AU Jolls, C.L.
DT 1980
TI Phenotypic patterns of variation in biomass allocation in Sedum lanceolatum
 Torr. at four elevational sites in the Front Range, Rocky Mountains, Colorado
SO Bulletin of the Torrey Botanical Club, 107:65-70
DE Ecology
; Genetics
; University of Colorado
; Mountain Research Station - Location
; A-1 Climate Station
; Angiosperms
; Atmospheric Chemistry
; Climate - Discussion of
; Biomass
; Demography
; Reproduction
AB None
$
CL 0488
AU Jolls, C.L.
DT 1980
TI Variation in the reproductive biology of Sedum lanceolatum Torr.
 (Crassulaceae) along an elevational gradient in the Front Range, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 154 pp.
DE Dissertation
; Ecology
; University of Colorado
; Mountain Research Station - Location
; A-1 Climate Stat
2000
ion
; Angiosperms
; Atmospheric Chemistry
; Climate - Discussion of
; Demography
; Reproduction
AB None
$
CL 0490
AU Jolls, C.L.
; Bock, J.H.
DT 1983
TI Seedling density and mortality patterns among elevations in Sedum
 lanceolatum
SO Arctic and Alpine Research, 15:119-126
DE Ecology
; University of Colorado
; Mountain Research Station - Location
; Angiosperms
; Altitude
; Demography
AB None
$
CL 0489
AU Jolls, C.L.
DT 1982
TI Plant population biology above timberline: Biotic selective pressures and
 plant reproductive success
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37, 83-95
DE Ecology
; Long-Term Ecological Research Program
; Angiosperms
; Altitude
; Climate - Discussion of
; Demography
; Bioenergetics
; Productivity
; Reproduction
; NWTLTER
AB None
$
CL 0492
AU Judson, J.A.
DT 1965
TI The weather and climate of a high mountain pass in the Colorado Rockies
SO U.S. Forest Service Research Paper, RM-16. 28 pp.
DE Climatology
; Niwot Ridge
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0494
AU Kapoor, B.M.
; Love, A., 1979
TI Chromosomes of Rocky Mountain Ranunculus
SO Caryologia, 23(4):575-594
DE Genetics
; Taxonomy & systematics
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
AB None
$
CL 0496
AU Keigley, R.B.
DT 1984
TI Effects of experimental manipulations on Kobresia myosuroides
SO Journal Colorado-Wyoming Academy of Sciences, 16(1):15. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Nitrogen
; Fertilizers
AB None
$
CL 0496a
AU Keigley, R.B.
DT 1987
TI Effect of experimental treatments on Kobresia myosuroides with implications
 for the potential effect of acid deposition
SO Ph.D. dissertation, University of Colorado, Boulder. 117 pp
DE Dissertation
; Ecology
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Angiosperms
; Acid Deposition
; Growth (Development)
; Phenology
; Demography
; Disturbances
; Precipitation
; NWTLTER
AB None
$
CL 0498a
AU Kelly, T.J.
; Stedman, D.H.
DT 1980
TI Effect of urban sources on acid precipitation in the western United States
SO Science, 210:1043
DE Technical Report
; Atmospheric Sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
; Management
AB None
$
CL 0499
AU Kelso, S.
DT 1980
TI Management of the Niwot Ridge biosphere reserve
SO M.A. thesis, University of Colorado, Boulder. 159 pp.
DE Thesis
; Management
; Mountain Research Station - Affiliation
; Niwot Ridge
AB None
$
CL 0502
AU Khanna, K.R.
DT 1967
TI A cytological investigation of the mosses of the Rocky Mountains
SO University of Colorado Studies, Series in Biology, 26. 39 pp.
DE Genetics
; Taxonomy & systematics
; University of Colorado
; Niwot Ridge
; Bryophytes
AB None
$
CL 0502b
AU Kienast, F.
; Schweingruber, F.H.
; Braker, O.U.
; Schar, E.
DT 1987
TI Tree-ring studies on conifers along ecological gradients and the potential
 of single-year analyses
SO Canadian Journal of Forest Research 17:683-696.
DE article
; Paleoecology
; Mountain Research Station
; Conifers
; altitude
; climate - discussion of
; tree
AB None
$
CL 0502a
AU Kienast, F.
; Schweingruber, F.H.
DT 1986
TI Dendroecological studies in the Front Range, Colorado, USA
SO Arctic and Alpine Research, 18(3): 277-288
DE Journal
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Conifers
; Climate - Discussion of
; Stratigraphy
; Community
; Growth (Development)
; Tree
; Paleoecology
AB None
$
CL 0502aa
AU Kienast, F.
DT 1985
TI Dendrooekologische Untersuchungen an hohenprofilen aus verschiedenen
 Klimabereichen
SO Ph.D. dissertation, University of Zurich, Zurich, 132 pp
DE dissertation
; paleoecology
; Mountain Research Station
; A-1 to D-1
; conifers
; altitude
; climate - discussion of
; tree
AB None
$
CL 0508
AU Kilburn, P.D.
DT 1965
TI Floras of the tundra treeless ecosystem
SO Natural History, 74(7):52-59
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Altitude
; Climate - Discussion of
; Distribution
AB None
$
CL 0509a
AU Kline, M.L.
DT 1986
TI Wetland influence on substrate retention of dissolved organic carbon in two
 subalpine stream ecosystems
SO M.A. thesis, University of Colorado, Boulder, 78 pp
DE article
; hydrology
; soil sciences
; Long-Term Ecological Research Program
; Boulder City Watershed
; chemistry
; carbon
; stream
; watershed
; NWTLTER
AB None
$
CL 0510
AU Kling, G.W.
; Grant, M.C.
DT 1984
TI Acid precipitation in the Colorado Front Range: An overview with time
 predictions for significant effects
SO Arctic and Alpine Research, 16:321-329
DE Overview
; Atmospheric sciences
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
AB None
$
CL 0513
AU Knowles, M.H.
DT 1980
TI Genetic variation of lodgepole pine over time and microgeographic space
SO Ph.D. dissertation, University of Colorado, Boulder. 114 pp.
DE Dissertation
; Genetics
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Mountain Research Station - Location
; B-1 Climate Station
; Conifers
; Tree
AB None
$
CL 0512
AU Knowles, M.H.
DT 1978
TI Genetic characteristics associated with growth in ponderosa pine
SO M.S. thesis, University of Colorado, Boulder. 81 pp.
DE Thesis
; Genetics
; University of Colorado
; B-1 Climate Station
; Conifers
; Growth (Development)
; Tree
AB None
$
CL 0515
AU Knowles, P.
; Grant, M.C.
DT 1983
TI Age and size structure analyses of Engelmann spruce, ponderosa pine,
 lodgepole pine and limber pine in Colorado
SO Ecology, 64:1-9
DE Ecology
; Mountain Research Station - Affiliation
; A-1 Climate Station
; B-1 Climate Station
; C-1 Climate Station
; Conifers
; Altitude
; Demography
; Morphological
; Growth (Development)
; Tree
AB None
$
CL 0516
AU Knowles, P.
; Grant, M.C.
DT 1985
TI Genetic variation of lodgepole pine over time and microgeographic space
SO Canadian Journal of Botany, 63:723-727. In Press
DE Ecology
; University of Colorado
; A-1 Climate Station
; B-1 Climate Station
; C-1 Climate Station
; Tree
; Genetics
AB None
$
CL 0514
AU Knowles, P.
; Grant, M.C.
DT 1981
TI Genetic patterns associated with growth variability in ponderosa pine
SO American Journal of Botany, 68:942-946
DE Genetics
; University of Colorado
; B-1 Climate Station
; Conifers
; Growth (Development)
; Tree
AB None
$
CL 0517
AU Knowles, P.
; Mitton, J.B.
DT 1980
TI Genetic heterozygosity and radial growth variability in Pinus contorta
SO Silvae Genetica, 19:114-117
DE Ecology
; Genetics
; Mountain Research Station - Affiliation
; A-1 Climate Station
; B-1 Climate Station
; C-1 Climate Station
; Conifers
; Growth (Development)
; Tree
AB None
$
CL 0518
AU Koerner, J.M.
DT 1969
TI Krummholz influences on alpine snow accumulations
SO M.A. thesis, University of Colorado, Boulder. 115 pp.
DE Thesis
; Ecology
; University of Colorado
; Niwot Ridge
; Conifers
; Snow
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 1484
AU Kolesar, S.E.
; McKnight, D.M.
; Waters, S.B.
DT 2002
TI Late fall phytoplankton dynamics in three lakes, Rocky Mountain National Park
SO Hydrobiologia v. 472 pp. 249-263
DE phytoplankton
; alpine lakes
; autumn
; water quality
AB We studied phytoplankton population dynamics during the month preceding formation of ice cover in three small subalpine lakes in Rocky Mountain National Park, Colorado, U.S.A. The outflow from Emerald Lake, which is surrounded by talus, flows into Dream Lake, which is surrounded by sub-alpine forest. Nymph Lake is a lower seepage lake with abundant macrophytes in summer. The major ion concentrations in the three lakes were similar during the study, although Emerald and Dream Lakes had higher concentratio
2000
ns of nitrate and silica than Nymph Lake. A principal component analysis (PCA) showed that the phytoplankton in Emerald and Dream Lakes were distinct from the phytoplankton in Nymph Lake. The species composition changed in each lake during the late fall. The patterns of change in Emerald and Dream Lakes were similar on the PCA diagram despite the greater abundance of diatoms in Dream Lake and the decreasing flow from Emerald Lake into Dream Lake during the fall. In Nymph Lake, a progressive shift in species distribution occurred with a decrease in the most abundant chlorophyte, Chlamydomonas sp., and increases in several species, including two chrysophytes and the diatom Eunotia sp. The marked change in species composition in all three lakes suggests that phytoplankton populations are influenced by changes in water temperatures and incident solar radiation that occur during the late fall. We also compared these data with phytoplankton data for two fall periods from two other hydrologically connected Rocky Mountain lakes. PCA analysis showed that the difference between years was greater than the change during the fall and that the fall species composition in these two lakes was distinct from that in Emerald and Dream Lakes or in Nymph Lake. Studying phytoplankton dynamics in alpine and sub-alpine lakes may offer clues as to how these ecosystems may respond to projected climate changes in the Rocky Mountain region, such as warmer temperatures and later formation of ice-cover.$
CL 0523
AU Komarkova, V.
DT 1984
TI The recovery of vegetation after disturbance in the Colorado alpine
 Long-Term Ecological Research (LTER) study area
SO Bulletin of Ecological Society of America, 65(2):67. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Water
; Community
; Disturbances
; Revegetation
AB None
$
CL 0523c
AU Komarkova, V.
; Peters, A.
; Kamani, G.
; Jones, W.
; Howard, V.
; Gordon, H.
; Southwick, K.
DT 1988
TI Natural recovery of plant communities on disturbance plots and history of
 land use in the Niwot Ridge/Green Lakes Valley, Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Working Paper 88/1. 46
 pp
DE Data Report
; Map
; Long-Term Ecological Research Program
; Ecology
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Plants
; Disturbances
; Recovery
AB None
$
CL 0523a
AU Komarkova, V.
DT 1988
TI Plant species and distribution on disturbance study areas, Niwot Ridge,
 Green Lakes Valley, Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Working Paper 88/2. 132
 pp
DE Data Report
; Map
; Long-Term Ecological Research Program
; Ecology
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Plants
; Disturbances
; Recovery
AB None
$
CL 0520
AU Komarkova, V.
DT 1976
TI Alpine vegetation of the Indian Peaks area, Front Range Colorado Rocky
 Mountains
SO Ph.D. dissertation, University of Colorado. 655 pp.
DE Dissertation
; Ecology
; Phytosociology
; Institute of Arctic and Alpine Research
; Indian Peaks Region
; Niwot Ridge
; Lichens
; Bryophytes
; Conifers
; Angiosperms
; Altitude
; Climate - Discussion of
; Community
; Distribution
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0523b
AU Komarkova, V.
; Bell, J.L.
DT 1988
TI Database management systems in scientific applications: use and bibliography
SO University of Colorado Long-Term Ecological Research Working Paper 88/3. 37
 pp
DE Data Report
; Management
; Ecology
; Long-Term Ecological Research Program
; Database
; Technique
AB None
$
CL 0524
AU Komarkova, V.
; Webber, P.J.
DT 1978
TI An alpine vegetation map of Niwot Ridge, Colorado
SO Arctic and Alpine Research, 10(1):1-29. Reprinted in: Ives, J.D. (ed.),
 1980: Geoecology of the Colorado Front Range. Boulder: Westview Press, 364-392
DE Map
; Ecology
; Phytosociology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Altitude
; Climate - Discussion of
; Community
; Distribution
AB None
$
CL 0521
AU Komarkova, V.
DT 1979
TI Alpine vegetation of the Indian Peaks area, Front Range, Colorado Rocky
 Mountains
SO In: Tuxen, R. (ed.), Flora et Vegetatio Mundi, VII. Vaduz: J. Cramer. xvi +
 591 pp. plus casebox of tables, maps, illus.
DE Ecology
; Phytosociology
; Institute of Arctic and Alpine Research
; Indian Peaks Region
; Niwot Ridge
; Lichens
; Bryophytes
; Conifers
; Angiosperms
; Altitude
; Climate - Discussion of
; Community
; Distribution
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0522
AU Komarkova, V.
DT 1980
TI Classification and ordination of the Indian Peaks area, Colorado Rocky
 Mountains
SO Vegetatio, 42:149-163
DE Ecology
; Institute of Arctic and Alpine Research
; Indian Peaks Region
; Angiosperms
; Niwot Ridge
AB None
$
CL 1205
AU Komarkova, V.
; Bell, J.L.
DT 1986
TI Characteristics of scientific databases and database management systems
SO In: Michener, W.K. (ed.), Research data management in the Ecological
 Sciences.  Columbia, S.C.: University of South Carolina Press, 39-60
DE NWTLTER
; database
; data management
AB None
$
CL 0524a
AU Komhyr, W.D.
; Gammon, R.H.
; Harns, T.B.
; Waterman, L.S.
; Conway, T. J.
; Taylor, W.R.
; Thoning, K.W.
DT 1985
TI Global atmosphere CO2 distribution and variations from 1968-1982 NOAA/GMCC
 flask sample data.
SO Journal of Geophysical Research 90:5567-5596
DE article
; NOAA - GMCC
; Atmospheric Science
; Niwot Ridge
; atmospheric chemistry
; carbon dioxide
AB None
$
CL 0525
AU Kooiman, M.
; Linhart, Y.B.
DT 1986
TI Structure and change in herbaceous communities of four ecosystems in the
 Front Range, Colorado
SO Arctic and Alpine Research, 18:97-110
DE Ecology
; Mountain Research Station - Affiliation
; A-1 Climate Station
; Community
; Angiosperms
; Conifers
AB None
$
CL 1326
AU Korb, J.
DT 1997
TI Vegetation dynamics in four ecosystems along an elevational gradient 
 in the Front Range of Colorado.
SO M.S. thesis, University of Colorado, Boulder.
DE NWTLTER
; vegetation dynamics
; climate
; elevation
AB None
$
CL1451
AU Korb, J.E.
; Ranker, T.A.
DT 2001
TI Changes in stand composition and structure between 1981 and 1996 in four Front Range plant communities in Colorado
SO Plant Ecology. vol. 157. pp.1-11
DE Gradient analysis
; Long-term study
; plant community ecology
; temporal change
; NWTLTER
AB We conducted a study analyzing the vegetation dynamics in four communities along an elevational gradient in the Front Range of the Colorado Rocky Mountains and compared our results with previous research conducted in 1981. The objective of this study was to determine whether the successional plant community trajectories hypothesized by the original investigator (Marr) in 1953 were consistent with plant community parameters measured in subsequent years. The ponderosa pine and Douglas-fir/ponderosa pine communitiesÆ herbaceous composition remained relatively constant between 1981 and 1996; however, a few individual species in both communities experienced significant changes in frequency over time. These individual species changes, along with dominant shifts in the forest canopy, were inconsistent with MarrÆs original successional hypotheses for these stands that stated the ponderosa pine stand would remain dominated by ponderosa pine and grassy openings and the Douglas-fir/ponderosa pine stand would eventually have equal dominance between the two tree species. The aspen herbaceous community experienced the most significant change between 1981 and 1996. Significant decreases in species richness and diversity were recorded along with large changes in species composition and frequencies of individual species. These changes were associated with successional changes in the forest canopy, which was congruent with MarrÆs successional hypothesis for this stand. The kobresia meadow herbaceous community showed the least change between 1981 and 1996 among the four communities; however, there was variation in frequency percentages for a few individu
2000
al species over time and a small turnover in species composition. MarrÆs hypothesis that this stand represented a climax community is consistent with our results.$
CL 0525a
AU Krantz, W.B.
; Gleason, K.J.
; Caine, N.
DT 1988
TI Patterned ground
SO Scientific American, 256:68-76
DE article
; geomorphology
; soil sciences
; Boulder City Watershed
; periglacial
; soil
; frost
; permafrost
AB None
$
CL 1283
AU Kratz, T.K.
; Magnuson, J.J.
; Bayley, P.
; Benson, B.J.
; Berish, C.W.
; Bledsoe, C.S.
; Blood, E.R.
; Bowser, C.J.
; Carpenter, S.R.
; Cunningham, G.L.
; Dahlgren, R.A.
; Frost, T.M.
; Halfpenny, J.C.
; Hansen, J.D.
; Heisey, D.
; Inouye, R.S.
; Kaufman, D.W.
; McKee, A.
; Yarie, J.
DT 1995
TI Temporal and spatial variability as neglected ecosystem properties: 
 Lessons learned from 12 North American ecosystems
SO Pp. 359-383. In: Rapport, D.J., C.L. Gaudet, and P. Calow (eds.). 
 Evaluating and Monitoring the Health of Large-Scale Ecosystems. NATO ASI 
 Series, Vol. I 28. Berlin: Springer-Verlag
DE NWTLTER
; variability
; ecosystem health
; Niwot Ridge
AB In this paper we describe general patterns exhibited by ecological
 parameters across a wide variety of ecosystem types. We attempt to
 answer three basic questions regarding ecological variability: (1) do
 climatic, edaphic, and biological parameters differ systematically in
 variability, (2) how is variability partitioned between spatial vs
 temporal components, and (3) to what extent are ecological parameters
 spatially or temporally coherent? We use data collected at 12 diverse
 North American ecosystems represented in the Long Term Ecological
 Research (LTER) network. In addition, to these general questions about
 patterns of variability and the effects of scale, we also used cross
 system comparisons of variability to test two smaller-scale ecological
 hypotheses: (1) that deserts are more variable than lakes temporally,
 but less variable spatially; and (2) that in predator-prey pairs, the
 smaller-shorter lived member of a pair is more temporally variable
 regardless of whether it is the prey or the predator. Additionally, 
 we were required to address two scale related questions: (1) what is 
 the effect of sampling unit size on measured variability; (2) how 
 sensitive is the observed variability to the temporal extent of the
 measurements. We also considered the degree to which observed 
 variability is related to degree of aggregation of the parameter
 measured.
$
CL 0526
AU Krear, H.R.
DT 1965
TI An ecological and ethological study of the pika (Ochotona princeps saxatilis
 Bangs) in the Front Range of Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 329 pp.
DE Dissertation
; Behavior
; Ecology
; University of Colorado
; Niwot Ridge
; Lagomorphs
; Altitude
; Demography
; Food Habits
; Movement
; Habitat
AB None
$
CL 0528
AU Kreibich, V.H.
DT 1966
TI Precipitation climatology of the Front Range in Colorado
SO M.A. thesis, University of Colorado, Boulder. 119 pp.
DE Thesis
; Climatology
; University of Colorado
; Rocky Mountain National Park - Location
; A-1 Climate Station
; Precipitation
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0529
AU Laiho, D.
DT 1983
TI A comparative evaluation of streamflow simulation models in a Colorado
 alpine environment
SO M.S. thesis. University of Colorado, Boulder. 104 pp.
DE Thesis
; Model
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Lake
; Stream
; Climate - Discussion of
; NWTLTER
AB None
$
CL 0529a
AU Lang, P.M.
; Steele, L.P.
; Martin, R.C.
DT 1990
TI Atmospheric methane data for the period 1986-1988 from the NOAA/CMDL global
 cooperative flask sampling network.
SO NOAA Technical Memorandum ERL CMDL-2. Climate Monitoring and Diagnostics
 Laboratory, Boulder CO 108pp
DE article
; NOAA - CMDL
; C-1
; Atmospheric Science
; atmospheric chemistry
AB None
$
CL 0529b
AU Lang, P.M.
; Steele, L.P.
; Martin, R.C.
; Masarie, K.a.
DT 1990
TI Atmospheric methane data for the period 1983-1985 from the NOAA/CMDL global
 cooperative flask sampling network
SO NOAA Technical Memorandum ERL CMDL-1  Climate Monitoring and Diagnostics 
 Laboratory, Boulder CO 90pp
DE article
; NOAA - CMDL
; Atmospheric Science
; Niwot Ridge
; atmospheric chemistry
AB None
$
CL 0531
AU Lanier, J.
DT 1978
TI Population dynamics of Rocky Mountain Douglas Fir (Pseudotsuga menziesii
 var. glauca) along an elevational gradient in the Front Range of Colorado
SO M.A. thesis, University of Colorado, Boulder. 97 pp.
DE Thesis
; Ecology
; University of Colorado
; B-1 Climate Station
; Conifers
; Altitude
; Demography
AB None
$
CL 1574
AU Larson, J.
DT 2005
TI Creeping Constructivism:  The interaction of formal and informal components of a university field course for pre- and in-service teachers
SO Paper presented at the annual meeting of the National Association for Research in Science Teaching.  Dallas, TX
DE NWTLTER
; Outreach
; teachers
AB None
$
CL 1241
AU Lauenroth, W.K.
; Urban, D.L.
; Coffin, D.P.
; Parton, W.J.
; Shugart, H.H.
; Kirchner, T.B.
; Smith, T.M.
DT 1993
TI Modeling vegetation structure-ecosystem process interactions across sites
 and ecosystems
SO Ecological Modelling 67:49-80
DE NWTLTER
; Saddle
; Niwot Ridge
; modeling
; Kobresia myosuroides
; soil water
; snow deoposition
AB We describe an approach to investigating and understanding the interactions
 between vegetation structure and ecosystem processes that uses simulation
 models as a framework for comparison and synthesis across ecosystems arrayed
 along environmental gradients. The models are individual-based vegetation
 simulators and compartment models of nutrient cycling and soil water
 relations. Applications focus on interactions and feedbacks between vegetation
 structure (species composition, size structure) and ecosystem processes (water
 balance, nutrient cycling), and how these relationships vary across
 environmental gradients. Preliminary results indicate that life-history traits
 of plants have a profound influence on system-level behaviors, and that
 differences between grasslands and forests can be attributed largely to
 contrasting traits of grasses and trees. Experiments with linked
 vegetation-ecosystem process models diverge from simulations with either model
 run independently, suggesting the importance of feedbacks between details of
 vegetation pattern and ecosystem processes. The development of a fully coupled
 vegetation-ecosystem process model that is sufficiently general to simulate
 systems dominated by multiple lifeforms presents several conceptual,
 logistical, and scaling challenges, but also provides for new opportunities in
 ecosystem theory.
$
CL 0534
AU LeDrew, E.F.
DT 1975
TI The energy balance of a mid-latitude alpine site during the growing season,
 1973
SO Arctic and Alpine Research, 7:301-314. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 288-301
DE Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Insolation
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0535
AU LeDrew, E.F.
DT 1975
TI The estimation of clear sky atmospheric emittance at high altitudes
SO Arctic and Alpine Research, 7:227-236
DE Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Insolation
AB None
$
CL 0533
AU LeDrew, E.F.
DT 1974
TI Radiation and energy budget of an alpine tundra in Colorado during the
 growing season, 1973
SO M.A. thesis, University of Colorado. 170 pp.
DE Thesis
; Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Insolation
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0532
AU LeDrew, E.F.
DT 1974
TI Five-day means of radiation data and miscellaneous climatic data for Barrow
 and Eagle Summit, Alaska and the Niwot Ridge, Saddle and Como stations in the
 Front Range, Colorado
SO U.S. Tun
2000
dra Biome Data Report, 74-39. 26 pp.
DE Data report
; Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Insolation
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0537
AU LeDrew, E.F.
; Weller, G.
DT 1978
TI A comparison of the radiation and energy balance during the growing season
 for arctic and alpine tundra
SO Arctic and Alpine Research, 10:665-678
DE Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Insolation
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0536
AU LeDrew, E.F.
; Emerick, J.C.
DT 1974
TI A mechanical balance-type lysimeter for use in remote environments
SO Agricultural Meteorology, 13:253-258
DE Technique
; Climatology
; U.S. International Biological Programme
; Niwot Ridge
; Precipitation
; Water
; Evapotranspiration
AB None
$
CL 0538
AU Lee, W.T.
DT 1900
TI The glacier of Mt. Arapahoe, Colorado
SO Journal of Geology, 8:647-654
DE Glaciology
; History
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0541a
AU Levy, H. II.
; Mahlman, J.D.
; Moxim W.J.
DT 1985
TI Tropospheric ozone: The role of transport
SO Journal of Geophysical Research 90:3753-3772
DE article
; Atmospheric Science
; C-1
; atmospheric chemistry
; climate change
; ozone
AB None
$
CL 0547
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1980
TI Changes in the output of ions from a watershed as a result of acidification
 of precipitation
SO Ecology, 60:1093-1097
DE Climatology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Watershed
; Chemistry
AB None
$
CL 0544
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1978
TI Sampling and chemical interpretation of precipitation for mass balance
 studies
SO Water Resources Research, 14:1098-1104
DE Climatology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Chemistry
AB None
$
CL 0546
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1980
TI Acid precipitation in the western United States
SO Science, 207:176-177
DE Climatology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Chemistry
AB None
$
CL 0549
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1980
TI Reply to a comment on acid precipitation in the western U.S.
SO Science, 210:1043
DE Climatology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Chemistry
AB None
$
CL 0543
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1978
TI Methodological considerations affecting the sampling of precipitation for
 ecological nutrient studies
SO Water Resources Research, 14:1098-1104
DE Technique
; Climatology
; Hydrology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Chemistry
AB None
$
CL 0550a
AU Lewis, W.M., Jr.
; Grant, M.C.
; Hamilton, S.K.
DT 1985
TI Evidence that filterable phosphorus is a significant atmospheric link in the
 phosphorus cycle
SO Oikos, 45:428-432
DE article
; ecology
; atmospheric science
; University of Colorado
; Mountain Research Station
; atmospheric chemistry
; biochemical
; nutrients
AB None
$
CL 0542
AU Lewis, W.M., Jr.
DT 1982
TI Changes in pH and buffering capacity of lakes in the Colorado Rockies
SO Limnology and Oceanography, 27:162-172
DE Hydrology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Acid Deposition
; Lake
; Chemistry
AB None
$
CL 0548
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1980
TI Relationships between snow cover and winter losses of dissolved substances
 from a mountain watershed
SO Arctic and Alpine Research, 12:11-17
DE Hydrology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Snow
; Water
; Chemistry
; Acid Deposition
AB None
$
CL 0545
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1979
TI Relationships between stream discharge and yield of dissolved substances
 from a Colorado mountain watershed
SO Soil Science, 128(6):353-363
DE Hydrology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Precipitation
; Stream
; Watershed
; Chemistry
AB None
$
CL 0551
AU Lewis, W.M., Jr.
; Grant, M.C.
; Saunders, J.
DT 1984
TI A precipitation chemistry network study of the State of Colorado, 1982-1983
SO Water Resources Research, 20:1691-1740
DE Climatology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Precipitation
; Chemistry
; C-1 Climate Station
AB None
$
CL 0550
AU Lewis, W.M., Jr.
; Grant, M.C.
DT 1981
TI Effect of the May-June Mount St. Helens eruptions on precipitation chemistry
 in central Colorado
SO Atmospheric Environment, 15:1539-1542
DE Climatology
; Mountain Research Station - Affiliation
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Chemistry
; Disturbances
AB None
$
CL 1397 
AU Ley, R.E.
; Lipson, D.A.
; Schmidt, S.K.
DT 2001
TI Microbial biomass levels in barren and vegetated high altitude talus 
  soils
SO Soil Science Society of America Journal 65:111-117.
DE None
AB None
$
CL1465
AU Ley, R.E. 
; Schmidt, S.K.
DT 2002
TI Fungal and bacterial responses to phenolic compounds and amino acids in high altitude barren soils.
SO Soil Biology and Biochemistry 34: 989-996
DE NWTLTER
AB None
$
CL1555
AU Ley, R.L
; Williams, M.W.
; Schmidt, S.K.
DT 2004
TI Microbial population dynamics in an extreme environment:controlling factors in talus soils at 3750 m in the Colorado Rocky Mountains
SO Biogeochemistry vol. 68 pp. 313-335
DE NWTLTER
; Extreme environment
; Mars
; Microbial biomass
; N deposition
; Seasonal dynamics
; Talus unvegetated soils
AB High elevation talus soils are extreme environments for life.They are pertinent to the hydrology and biochemical cycling of high elevation ecosystems that supply drinking water to major metropolitan areas,and are undergoing change as a result of N deposition.As biological systems,they are virtually unstudied.In order to gain a basic understanding of these important systems,we studied the seasonal timing of C inputs and microclimate,and how they corresponded to microbial biomass dynamics,in vegetated and unvegetated soils from a high altitude talus slope at 3750 m in the Colorado Front Range.The soil microclimate was described by soil moisture and temperature measurements;C inputs were estimated with measures of eolian dust inputs and photosynthetically active radiation (PAR).The biomass of different microbial functional groups (glutamate and salicylate mineralizers adapted to different temperatures) was estimated seasonally over 3 years.We found that the soil microclimate can be divided into three distinct seasons: Winter,with free water and temperature between -2.9 and 0 degree C; spring, characterized by wet isothermal soils (0 degree C) ;and summer,characterized by hot (mean 10.3 C ; range 0-29.3 C) dry soils occasonally wetted by precipitation.The highest OM inputs to unvegetated soils occurred in spring; PAR only reached soils in the summer.In unvegetated soils,the biomass of glutamate mineralizers (GM) was highest in spring and summer.In contrast,the GM of vegetated soils had highest biomass in the winter when plants were senesced.In both unvegetated and vegetated soils,salicylate mineralizers (SM)had greater biomass levels in the summer when temperatures were highest.$
CL 0552
AU Light, J.T.
; Nelson, W.C.
; Windell, J.T.
DT 1982
TI The vital statistics of unexploited brook trout populations in the alpine
 lakes, Front Range, Colorado
SO Journal Colorado-Wyoming Academy of Sciences, 14(1):14. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Fish
; Lake
; Demography
; Growth (Development)
AB None
$
CL 0554a
AU Lin, X.
; Trainer, M.
; Liu, S.C.
DT 1988
TI On the nonlinearity of the tropospheric ozone production
SO Journal of Geophysical Research 93:15879-15888.
DE article
; Atmospheric Science
; C-1
; atmospheric chemistry
; climate ch
2000
ange
; ozone
AB None
$
CL 0554b
AU Linhart, Y.B.
; Tomback, D.F.
DT 1985
TI Seed dispersal by nutcrackers causes multi-trunk growth form in pines
SO Oecologia, 67:107-110
DE article
; ecology
; genetics
; Mountain Research Station
; Boulder City Watershed
; conifers
; birds
; seed
; growth
AB None
$
CL 1336
AU Lipson D.A.
; Monson R.K.
DT 1998
TI Plant-microbe competition for soil amino acids in the alpine tundra:
 effects of freeze-thaw and dry-rewet events
SO Oecologia 113:406-414
DE NWTLTER
; alpine tundra
; Kobresia myosuroides
; freezing
; drying
; nitrogen cycle
AB Amino acids have been shown to be a potentially significant N source for 
 the alpine sedge, Kobresia myosuroides. We hypothesised that freeze-thaw
 and dry-rewet events allow this plant species increased access to amino
 acids by disrupting microbial cells, which decreases the size of competing
 microbial populations, but increases soil amino acid concentrations. To
 test this hypothesis, we characterized freeze-thaw and dry-rewet events in
 the field and simulated them in laboratory experiments on plant-soil
 microcosms. In one experiment, 15N, 13C-[2]-glycine was added to microcosms
 that had previously been subjected to a freeze-thaw or dry-rewet event, and
 isotopic concentrations in the plant and microbial fractions were compared
 to non-stressed controls. Microbial biomass and uptake of the labeled
 glycine were unaffected by the freezing and drying treatments, but microbial
 uptake of 15N was decreased by climatic disturbance, and uptake in plants that
 had been frozen appeared to be dependent on the severity of the freeze. The
 fact that intact glycine was absorbed by the plants was confirmed by near
 equal enrichment of plant tissues in 13C and 15N. Plants under optimal
 conditions recovered 3.5% of the added 15N and microbes recovered 5.0%.
 The majority of the 13C and 15N label remained in a non-extractable fraction
 in the bulk soil. To better understand the isolated influences of environmental
 perturbations on soil amino acid pools and population sizes of amino-acid 
 utilizing microbes, separate experiments were performed in which soils,
 alone, were subjected to drying and rewetting of freezing and thawing. 
 Potential respiration of glycine and glutamate (substrate-induced respirations;
 SIR) by the soil microbial communities was unaffected by a singe freeze-thaw 
 event. Glycine SIR was decreased slightly (~10%) by the most extreme drying
 treatment, but glutamate SIR was not significantly affected. Freezing lowered
 the concentration of water-extractable amino acids while drying increased
 their concentration. We interpret the surprising former result as either
 a decrease in proteolytic activity in frozen soils relative to amino acid
 uptake, or a stimulation in microbial uptake by physical nutrient release
 from the soil. We conclude that climatic disturbance does not provide 
 opportunities for increased amino acid uptake by K. myosuroides, but that
 this plant competes well for amino acid N under non-tressed conditions,
 especially when soils are warm. We also note that this alpine tundra microbial
 community's high resistance to freeze-thaw and dry-rewet events is novel
 and contrasts with studies in other ecosystems. 
$
CL1470
AU Lipson, D.
; Nasholm, T
DT 2001
TI The unexpected versatility of plants: organic nitrogen use and availability in terrestrial ecosystems
SO OECOLOGIA 128 (3) pp305-316
DE amino acid uptake
; organic nitrogen availability
; plant-microbe competition
; N-15 NATURAL-ABUNDANCE
; MICROBIAL-POPULATION DYNAMICS
; SEDGE KOBRESIA MYOSUROIDES
; AMINO-ACID-TRANSPORT
; ALPINE TUNDRA
; INORGANIC NITROGEN
; MYCORRHIZAL FUNGI
; RICINUS-COMMUNIS
; SOIL-NITROGEN
; ECTOMYCORRHIZAL FUNGI
AB The recently recognized importance of organic nitrogen (ON), particularly amino acids, to plant nutrition in many types of agricultural and natural ecosystems has raised questions about plant-microbe interactions, N availability in soils, and the ecological implications of ON use by plants in the light of climate change and N pollution. In this review we synthesize the recent work on availability and plant uptake of amino acids with classic work on ON in soils. We also discuss recent work on the use of natural abundance levels of N-15 to infer N sources for plants. Reliance on ON is widespread among plants from many ecosystems. Authors have reached this conclusion based on laboratory studies of amino acid uptake by plants in pure culture, amino acid concentrations in soils, plant uptake of isotopically labeled amino acids in the field and in plant-soil microcosms, and from plant natural abundance values of N-15. The supply of amino acids to plants is determined mainly by the action of soil proteolytic enzymes, interactions between amino acids and the soil matrix, and competition between plants and microbes. Plants generally compete for a minor fraction of the total amino acid flux, but in some cases this forms a significant N resource, especially in ecosystems where microbial biomass undergoes large seasonal fluctuations and contributes labile ON to the soil. A quantitative understanding of ON use by plants is confounded by incomplete data on partitioning of ON between plants, mycorrhizal fungi, and competing soil microbes. Further research is needed to predict the ecological implications of ON use by plants given the influence of climatic change and N pollution. $
CL 1353
AU Lipson, D.A.
; Raab, T.K.
; Schmidt, S.K.
; Monson, R.K.
DT 1999
TI Variation in competitive abilities of plants and microbes for specific amino acids
SO Biology and Fertility of Soils 29:257-261.
DE NWTLTER
; alpine nitogen cycle
; amino acids
; Kobresia myosuroides
; organic nitrogen
; plant-microbe competition
AB Microbes are assumed to possess strong competitive advantages over plants for uptake
 of nutrients from the soil. The finding that non-mycorrhizal plants can obtain a 
 significant fraction of their N requirement from soil amino acids contradicts this 
 assumption. The amino acid glycine (Gly) has been used as a model amino acid in many
 recent studies. Our preliminary studies showed that Gly was a poor substrate for microbial
 growth compared to other amino acids. We tested the hypothesis that the alpine sedge 
 Kobresia myosuroides competes better for Gly than for other amino acids because of decreased
 microbial demand for this compound. Soil microbial populations that could grow using Gly
 as a sole carbon source were about 5 times lower than those that could grow on glutamate
 (Glu). Gly supported a significantly lower population than any of the ten other amino
 acids tested except serine. In contrast, K. myosuroides took up Gly from hydroponic solution
 at faster rates than Glu. In plant-soil microcosms, plants competed with soil microbes 3.25
 times better for Gly than for Glu. We conclude that the low microbial demand and the rapid
 plant uptake of Gly relative to other amino acids allow Gly to be an especially important
 nitrogen source for K. myosuroides.
$
CL 1360
AU Lipson, D.A.
; Schmidt, S.K.
; Monson, R.K.
DT 1999
TI Links between microbial population dynamics and nitrogen availability in an alpine
 ecosystem
SO Ecology 80:1623-1631
DE NWTLTER
; alpine tundra
; Kobresia myosuroides
; microbial population dynamics
; N uptake
; nitrogen availability
; organic nitrogen
; soil microorganisms
; soil proteas activity
; substrate-induced growth response
; temporal partitioning 
AB Past studies of plant-microbe interactions in the alpine nitrogen cycle have revealed 
 a seasonal separation of N use, with plants absorbing N primarily during the summer 
 months and microbes immobilizing N primarily during the autumn months. On the basis 
 of these studies, it has been concluded that competition for N between plants and 
 microbes is minimized along this seasonal gradient. In this study, we examined more 
 deeply the links between microbial population dynamics and plant N availability in an 
 alpine dry meadow. We conduc
2000
ted a year-round field study and performed experiments on
 isolated soil microorganisms. Based on previous work in this ecosystem, we hypothesized 
 that microbial biomass would decline before the plant growing season and would release 
 N that would become available to plants. Microbial biomass was highest when soils were 
 cold, in autumn, winter, and early spring. During this time, N was immobilized in 
 microbial biomass. After snow melt in spring, microbial biomass decreased. A peak in 
 the soil protein concentration was seen at this time, followed by peaks in soil amino 
 acid and ammonium concentrations in late June. Soil protease rates were initially high 
 after snow melt, decreased to below detection limits by midsummer, and partially 
 recovered by late summer. Proteolytic activity in soil was saturated early in the 
 growing season and became protein limited later in the summer. We concluded that the 
 key event controlling N availability to alpine plants occurs after snow melt, when 
 protein is released from the winter microbial biomass. This protein pulse provides 
 substrate for soil proteases, which supply plants with amino acids during the growing 
 season. On average, microbial biomass was lower in the summer than at other times, 
 although the biomass fluctuated widely during the summer. Within the summer months, 
 maximum numbers of amino-acid-degrading microorganisms and the maximum amount of 
 microbial biomass coincided with the peak in soil amino acids, when plants are most 
 active. All bacterial strains isolated from this summer community had the ability to 
 grow rapidly on low concentrations of amino acids and to degrade protein. This explains 
 the previously observed result that the soil microbial biomass can compete strongly 
 with plants for organic N, despite the seasonal offset of maximum plant and microbial 
 N uptake.
$
CL 1375
AU Lipson, D.A.
; Schmidt, S.K.
; Monson, R.K.
DT 2000
TI Carbon availability and temperature control the post-snowmelt
 decline in alpine soil microbial biomass
SO Soil Biology and Biochemistry 32:441-448
DE NWTLTER
; carbon
; soil
; microbial biomass
AB In Colorado alpine dry meadow soils, microbial biomass has been 
 observed to increase during fall and winter and to rapidly decline 
 after snowmelt in the spring.  It has been shown that these 
 microbial population dynamics are linked to N availability to 
 alpine plants, but the underlying mechanisms have not been explained.  
 We hypothesized that: (1) freeze-thaw events in the spring cause 
 reduction of the microbial biomass, (2) the winter microbial 
 community is sensitive to prolonged temperatures above 0 degrees C, 
 and (3) the increase of biomass in fall and its decline in spring are 
 due to changes in C availability.  We performed laboratory experiments 
 to test the effect of temperature regime on soil microbial biomass, 
 respiration and C availability, and made seasonal measurements of C pools.  
 Soil microbial biomass was unaffected by freeze-thaw events in which 
 realistic rates of freezing and thawing was used.  Some significant 
 effects were observed at faster freezing rates.  Despite this tolerance 
 to temperature flunctuations, the winter microbial community showed sensitivity 
 to prolonged temperatures above 0 degrees C.  This effect may have been 
 caused indirectly by an effect of temperature on substrate availability.  
 Two week incubations at increased temperatures caused a reduction in the 
 quantity of extractable organic C in the soil.  The soil concentrations of 
 cellulose and hot water-soluble organic C were the lowest in the summer and 
 the highest in spring and autumn, mirroring previously measured patterns of 
 microbial biomass.  Respiration rates in the soils collected before snowmelt 
 were high at 0 degrees C, and did not respond immediately to addition of 
 glutamate.  At 22 degrees C, or after a two week incubation at 0 degrees C, 
 respiration in these soils became substrate-limited. 
 Respiration rates in soils collected during the summer were very low at 0 
 degrees C, but responded immediately to glutamate addition at both 0 and 22 
 degrees C.These results show that the C balance of the soil mirobial biomass 
 undergoes a critical shift between winter and summer due to an ncrease in 
 temperature and a corresponding decrease in C availability.  This shift could 
 explain the decline in microbial biomass after snowmelt.
$
CL 1398 
AU Lipson, D.A.
; Raab, T.K.
; Schmidt, S.K.
DT 2001
TI An empirical model of amino acid transformation in an alpine soils 
SO Soil Biology & Biochemistry 33:189-198.
DE None
AB None
$
CL 1291
AU Lipson, D.A.
; Raab, T.K.
; Monson, R.K.
DT 1996
TI Delta-acetylornithine as a major nitrogen storage compound in 
 Bistorta Bistortoides
SO Phytochemistry 41 (1):29-30
DE NWTLTER
; Bistorta bistortoides
; Polygonaceae
; American bistort
; Alpine plants
; nitrogen storage
; non-protein amino acids
; delta-acetylornithine
AB Delta-acetylornithine was found to vary seasonally and in response to 
 nitrogen availability in the rhizones of the alpine herb, Bistorta bistortoides
 (Pursh). Delta-acetylornithine accounts for 38% of the free amino acid pool 
 and up to 12% of the total nitrogen in rhizomes. It is concluded that this
 compound plays an important role in nitrogen storage in this species.
$
CL 1351
AU Lipson, D.A.
; Schadt, C.W.
; Schmidt, S.K.
; Monson, R.K.
DT 1999
TI Ectomycorrhizal transfer of amino acid-nitrogen to the alpine sedge
 Kobresia myosuroides
SO New Phytologist 142:163-167
DE NWTLTER
; alpine
; amino acid
; ectomycorrhizas
; Kobresia myosuroides
; nitrogen
; Cyperaceae
; sedge
AB Previous work in the Colorado alpine ecosystem has shown that amino acids
 are a potentially important N source for the sedge, Kobresia myosuroides.
 This plant is the only known sedge to harbour associations with ectomycorrhizal
 fungi. The aim of the present work was to test the hypothesis that these 
 ectomycorrhizas transfer N from amino acids in the soil solution to the host
 plant, and thereby have an important role in the N nutrition of this species.
 We used a two-chamber system (rhizoboxes) in which K. myosuroides plants were
 separated from a soil chamber by nylon mesh that allowed fungal hyphae, but not
 plant roots, to cross it. Injections of [15N,2-13C]glycine were made into the soil
 chamber. The hyphal crossings on half of the rhizoboxes were regularly disrupted 
 to control for leakage of label across the barrier. Plants in the intact rhizoboxes
 showed significantly higher 15N enrichment that those in controls, and mycorrhizal
 root tips were significantly more enriched than bulk roots. The mycorrhizas
 transferred an average of 1.3% of the added 15N label to plants, a figure comparable
 to those obtained in previous studies in which plant roots were directly exposed
 to label. We conclude that fungal associations have an important role in the N
 nutrition of K. myosuroides by transferring N from amino acids to their hosts.
$
CL 1303
AU Lipson, D.A.
; Bowman, W.B.
; Monson, R.K.
DT 1996
TI Luxury uptake and storage of nitrogen in the rhizomatous alpine herb,
 Bistorta bistortoides
SO Ecology 77: 1277-1285
DE NWTLTER
; Bistorta bistortoides
; alpine tundra
; growth vs storage
; luxury uptake
; nitrogen, availibility
; nitrogen, costs and benefits
; nitrogen, fertilization
; nutrient uptake
; resource storage
; rhizome physiology
AB The patterns of luxury uptake and storage of nitrogen were studied
 in the rhizomatous alpine herb, Bistorta bistortoides (Pursh.). Nitrogen
 pools in the rhizome and shoot werer measured in fertilized and nonfertilized
 plants over two growing seasons (3-4 growing seasons after fertilization
 began). Fertilized plants stored more N in the rhizome throughout both
 seasons than did nonfertilized plants. Inflorescence, foliar, and preformed
 bud N concentrations and biomass production rate did not increase in response
 to fertilization. The increased stora
2000
ge of N without a concomitant influence
 on biomass production demonstrates that luxury uptake occurs in this species.
 Increased N storage in fertilized plants was accommodated by an increase in
 the amino acids arginine, the nonprotein amino acid, delta-acetylornithine,
 glutamine, and glutamate. Luxury uptake was accommodated entirely through
 filling of existing rhizome cells; no increased cell proliferation was
 found. Sucrose concentration was significantly lower in the recently produced
 rhizome tissue of fertilized plants, possibly reflecting the carbon costs of
 storing the additional N.
    During the first half of the season, fertilized plants relied more on
 stored N to drive growth, with translocation from reserves accounting for
 56% and 100% of the aboveground N requirement in nonfertilized and fertilized
 plants, respectively. In fertilized plants, the complete reliance on stored
 N indicates a decrease in current-season uptake of N during the period
 normally associated with the net N uptake in this species. This is interpreted
 as either (1) a seasonal shift in N uptake, or (2) a negative feedback between
 stored N and uptake that would constrain the continued accumulation of excess
 N and eliminate any long-term benefits of luxury N uptake in this species.
$
CL 1560
AU Lipson, D.A.
; Schmidt, S.K.
DT 2004
TI Seasonal changes in an alpine soil bacterial community in the Colorado Rocky Mountains
SO Appl. Environ. Microbiol. vol. 70 pp. 2867-2879
DE NWTLTER
; 16S RIBOSOMAL-RNA
; MICROBIAL BIOMASS
; SP-NOV
; PURE-CULTURE
; ARID SOILS
; GEN. NOV.
; IN-SITU
; DIVERSITY
; NITROGEN
; MEMBERS
AB The period when the snowpack melts in late spring is a dynamic time for alpine ecosystems. The large winter microbial community begins to turn over rapidly, releasing nutrients to plants. Past studies have shown that the soil microbial community in alpine dry meadows of the Colorado Rocky Mountains changes in biomass, function, broad-level structure, and fungal diversity between winter and early summer. However, little specific information exists on the diversity of the alpine bacterial community or how it changes during this ecologically important period. We constructed clone libraries of 16S ribosomal DNA from alpine soil collected in winter, spring, and summer. We also cultivated bacteria from the alpine soil and measured the seasonal abundance of selected cultured isolates in hybridization experiments. The uncultured bacterial communities changed between seasons in diversity and abundance within taxa. The Acidobacterium division was most abundant in the spring. The winter community had the highest proportion of Actinobacteria and members of the Cytophagal Flexibacter/Bacteroides (CFB) division. The summer community had the highest proportion of the Verrucomi-crobium division and of beta-Proteobacteria. As a whole, alpha-Proteobacteria were equally abundant in all seasons, although seasonal changes may have occurred within this group. A number of sequences from currently uncultivated divisions were found, including two novel candidate divisions. The cultured isolates belonged to the alpha-, beta-, and gamma-Proteobacteria, the Actinobacteria, and the CFB groups. The only uncultured sequences that were closely related to the isolates were from winter and spring libraries. Hybridization experiments showed that actinobacterial and beta-proteobacterial isolates were most abundant during winter, while the alpha- and gamma-proteobacterial isolates tested did not vary significantly. While the cultures and clone libraries produced generally distinct groups of organisms, the two approaches gave consistent accounts of seasonal changes in microbial diversity.
$
CL1455
AU Lipson, D.A.
; Schadt, C.W.
; Schmidt, S.K.
DT 2002
TI Changes in Soil Microbial Community Structure and Function in an Alpine Dry Meadow Following Spring Snow Melt
SO Microbial Ecology (http://link.springer.de/link/service/journals/00248/contents/01/1057/paper/body.html)
DE NWTLTER
AB None
$
CL 1402
AU Lipson, D.L. 
DT 1998
TI Plant-microbe interactions and organic nitrogen availability in an alpine   dry meadow
SO PhD dissertation, University of Colorado, Boulder. 170 pp.
DE None
AB None
$
CL 1299
AU Litaor M.I.
; Mancinelli R.
; Halfpenny J.C.
DT 1996
TI The influence of pocket gophers on the status of nutrients in
 alpine soils
SO Geoderma 70 (1996) 31-48
DE NWTLTER
; alpine
; nutrient cycling
; gophers
; soil 
AB Soil and soil solutions from the Martinelli Slope Experiment on
 Niwot Ridge, Front Range, Colorado (40 degrees 03 minutes N, 105 
 degrees 35 minutes W) were studied to evaluate the influence of 
 pocket gophers (Thomomys talpoides) on nutrient cycling in the alpine
 soil environment. Concentrations of total C, N, exchangeable Ca
 and K were significantly lower in gopher mound soils (P<0.05), whereas
 available NO3- and nitrogen fluxes were significantly higher (P>0.001).
 Silt and clay contents were significantly higher (P<0.01) in the surface
 horizons compared with the subsurface horizons of the intermounds, 
 whereas particle size distributions exhibited more homogenous profile 
 in the mounds. This pattern was explained by the mixing activity of 
 the pocket gophers. The biological homogenization strongly influenced 
 particle size distribution, bulk density, the availability of nutrients, 
 and especially modified the N cycle within the alpine soil environment.
$
CL 0557a
AU Litaor, M.I.
DT 1986
TI Geochemistry of alpine soils in the Colorado Front Range, with special
 reference to acid deposition
SO Ph.D. dissertation, University of Colorado, Boulder, 275 pp
DE dissertation
; soil sciencess
; Long-Term Ecological Research Program
; Boulder City Watershed
; acid deposition
; soil
; NWTLTER
AB None
$
CL1464
AU Litaor, M.I.
; Seastedt, T.R.
; Walker, D.A.
DT 2002
TI Spatial analysis of selected soil attributes across an alpine topographic/snow gradient
SO Landscape Ecology 17:71-85
DE NWTLTER
AB None
$
CL 0558c
AU Litaor, M.I.
DT 1988
TI Review of soil solution samplers
SO Water Resources Research, 24:727-733
DE Journal
; Technique
; Soil Sciences
; Long-Term Ecological Research Program
; Niwot Ridge
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Soils
; Watershed
; NWTLTER
AB None
$ 
CL 1256
AU Litaor, M.I.
; Keigley, R.B.
DT 1991
TI Geochemical equilibria of iron in sediments of the Roaring River 
 alluvial fan, Rocky Mountain National Park, Colorado 
SO Earth Surface Processes and Landforms 16: 533-546
DE NWTLTER
; redox potential
; iron mobility and precipitation
; Rocky Mountain National Park
AB None
$
CL 0559a
AU Litaor, M.I.
; Thurman, E.M.
DT 1988
TI Acid neutralizing processes in an alpine watershed, Front Range, Colorado,
 USA. I. Buffering capacity of dissolved organic carbon in soil solutions
SO Applied Geochemistry, 3:645-652
DE Journal
; Soil Sciences
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Acid Deposition
; Chemistry
; Precipitation
; Water
; Watershed
; NWTLTER
AB None
$
CL 0558aa
AU Litaor, M.I.
DT 1987
TI The influence of eolian dust on the genesis of alpine soils in the Front
 Range, Colorado
SO Soil Science Society of America Journal, 51:142-147
DE article
; soil sciences
; Long-Term Ecological Research Program
; Boulder City Watershed
; chemistry
; soil
; water
; NWTLTER
AB None
$
CL 1565
AU Litaor, M.I.
; Seastedt, T.R.
; Walker, M.D.
; Carbone, M.
; Townsend, A.
DT 2005
TI  The Biogeochemistry of Phosphorus across an alpine topographic/snow gradient
SO Geoderma vol. 124 pp. 49-61
DE NWTLTER
AB None.
$
CL 0558a
AU Litaor, M.I.
DT 1987
TI Soil interstitial waters.  I.  Review of field sampling techniques.  II.
 Study sites in the Green Lakes Valley and Niwot Ridge, Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Data Report 87/1. 26 pp
DE Data Report
; Soil Sciences
; Long-Term Ecological Research Program
; Technique
; Map
; Chemistry
; Saddle (Niwot Ridge)
; 
2000
Martinelli
; Boulder Watershed and Rainbow Lakes
; Soils
; Water
AB None
$
CL 1237
AU Litaor, M.I.
DT 1993
TI The influence of soil interstitial waters on the physiochemistry of major,
 minor and trace metals in stream waters of the Green Lakes Valley, Front
 Range, Colorado
SO Earth Surface Processes and Landforms 18: 489-504
DE NWTLTER
; soil solutions
; alpine soil environment
; anthropogenic influence
; Green Lakes Valley
AB The influence of soil interstitial waters on the physicochemical
 characteristics of major, minor and trace metals in stream waters of an alpine
 watershed, Front Range, Colorado was assessed. Dissolution of Ca-
 aluminosilicate minerals, ion exchange reactions and the magnitude of solute
 flux within the alpine soil environment account for most of the observed
 concentrations of major, minor and trace metals in the alpine stream waters.
 The rate of mineral dissolution and magnitude of solute flux during the summer
 of 1989 was greatly affected by anthropogenic disturbance which resulted in
 large amounts of colloidal material and freshly exposed mineral surfaces. The
 alpine ecosystem responded very quickly to this disturbance. The magnitude of
 solute flux in the soil environment was also highly dependent on the duration
 and intensity of rain events, as well as location of the site along the slope.
 Transport of most trace metals in the stream waters was achieved by adsorption
 onto colloidal surfaces of Al-Si hydroxides smaller than 0.45 um.
$
CL 1252
AU Litaor, M.I.
; Keigley, R.B.
DT 1993
TI Geochemistry of iron oxides in the Roaring River Alluvial Fan, Rocky
 Mountain National Park, Colorado
SO Pp 55-69 In: McCutchen, H.E., R. Herrmann, and D.R. Stevens (eds.).
 Ecological effects of the Lawn Lake Flood of 1982, Rocky Mountain National
 Park. United States Department of the Interior, National Park Service,
 Scientific Monograph NPS/NRROMO/NRSM-93/21, 214 pp.
DE NWTLTER
; Rocky Mountain National Park
; geochemistry
; iron oxides
; geomorphology
; organic carbon
AB The chemistry and mineralogy of iron oxides on the surface of the Roaring
 River alluvial fan in Rocky Mountain National Park, Colorado, were
 investigated. Buried soil organic matter and a high water table within the
 alluvial fan has produced a highly reduced environment that results in
 elevated dissolved and suspended iron (Fe) concentrations in the interstitial
 waters. The source of the iron is probably iron oxides within the buried soil
 and primary iron-bearing minerals such as hornblende, biotite, magnetite, and
 epidote in the sediments. When the iron-rich solutions reach the surface, the
 water rapidly oxidizes and amorphous ferric hydroxides precipitate. Between
 190 and 370 mmol of iron per kilogram of surficial material were precipitated
 within 2 months. Noticeable decreases in the total amount of organic carbon
 (C) and extractable iron (20 and 30%, respectively) in the buried soil were
 observed during the study (1985-87), which implies a significant reduction in
 iron dissolution and subsequent deposition across the alluvial fan.
$
CL 0558ab
AU Litaor, M.I.
DT 1988
TI Spatial and temporal variations of soil water constituents in an alpine
 watershed
SO Arctic and Alpine Research, 20:485-491
DE article
; soil sciences
; Long-Term Ecological Research Program
; Boulder City Watershed
; chemistry
; soil
; water
AB None
$
CL 0557aa
AU Litaor, M.I.
DT 1987
TI Aluminum chemistry: fractionation, speciation, and mineral equilibria of
 soil interstitial waters of an alpine watershed, Front Range, Colorado
SO Geochemica et Cosmochimica Acta, 51:1285-1295
DE article
; hydrology
; soil sciences
; Long-Term Ecological Research Program
; Boulder City Watershed
; chemistry
; soil
; water
; watershed
; NWTLTER
AB None
$
CL 0558d
AU Litaor, M.I.
DT 1988
TI Soil solution chemistry in an alpine watershed, Front Range, Colorado, USA
SO Arctic and Alpine Research, 20(4):485-491
DE Journal
; Technique
; Soil Sciences
; Long-Term Ecological Research Program
; Niwot Ridge
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Soils
; Watershed
; NWTLTER
AB None
$
CL 0558b
AU Litaor, M.I.
DT 1988
TI Reply to "Comments on 'The influence of eolian dust on alpine soils'"
SO Soil Science Society of America Journal, 52:301-302
DE Journal
; Technique
; Soil Sciences
; Long-Term Ecological Research Program
; Wind
; Soils
; NWTLTER
AB None
$
CL 1227
AU Litaor, M.I.
DT 1992
TI Aluminum mobility along a geochemical catena in an alpine watershed, Front
 Range, Colorado
SO Catena 19: 1-16
DE NWTLTER
; aluminum mobility
; Green Lakes Valley
; geochemical catena
; organic carbon
; base saturation
; soil buffering capacity
AB Soils and soil solutions were studied in order to assess the mobility of Al
 in an alpine watershed, Front Range, Colorado. The concept of a geochemical
 catena was invoked to evaluate the spatial relationships of Al and the
 elements that control its solubility in alpine soils. Organic C, exchangeable
 Al, silt and clay increased significantly (P<0.01) whereas base saturation and
 soil buffering capacity decreased significantly (P<0.01) downslope along the
 geochemical catena. This physicochemical pattern was explained by enhanced
 lateral flow within the surface horizons over the frozen subsurface horizons
 during the snowmelt season. Total reactive Al, total monomeric Al, and H+
 increase significantly in the subsurface horizons downslope (P<0.01) after a
 major summer storm event. The downslope increase of solutes in the subsurface
 horizons was attributed to vertical leaching coupled with lateral flow in the
 subsurface horizons during major summer precipitation events. Total reactive
 Al and total monomeric Al in the soil solutions were highly correlated with
 DOC along the geochemical catena. Soil and soil solutions should be studied
 simultaneously in order to explain alpine pedogenesis and contemporary changes
 in the Al cycle along the geochemical landscape.
$
CL 1204
AU Litaor, M.I.
DT 1986
TI The influence of eolian dust on the buffering capacity of alpine soils in
 the Front Range, Colorado
SO In: Pielke, R.A. (ed.), Proceedings of Symposium on acid deposition in
 Colorado - a potential or current problem; Local versus long-distance
 transport in the state.  Colorado State University, Pingree Park Campus,
 August 13-15, 1986.  Fort Collins, Colorado: Cooperative Institute for
 Research in Armospheric Sciences, 13-20
DE NWTLTER
; soil sciences
; acid deposition
; buffering
; Boulder City Watershed
AB None
$
CL 0557
AU Litaor, M.Z.
DT 1984
TI Soil buffering capacity in the Green Lakes Valley, Colorado Front Range
SO Bulletin of Ecological Society of America, 65(2):272. Abstract
DE Abstract
; Soil sciences
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Soil
; Chemistry
AB None
$
CL 0559
AU Litaor, M.Z.
; Thurman, E.M.
DT 1984
TI Soil interstitial waters chemistry in the Green Lakes Valley, Front Range,
 Colorado
SO Soil Science Society of America Annual Meeting, 1984, Las Vegas, NV.
 Abstract
DE Abstract
; Soil sciences
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Soil
; Water
; Glacier
AB None
$
CL 0558
AU Litaor, M.Z.
DT 1985
TI Soil genesis and soil water chemistry in the Green Lakes Valley, Colorado
 Front Range, 1982-1983
SO University of Colorado Long-Term Ecological Research Data Report, 85/2. 38
 pp.
DE Data report
; Soil sciences
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Soil
; Water
AB None
$
CL 1280
AU Liu, F.
; Williams, M.W.
; Yang, D.
; Melack, J.
DT 1995
TI Snow and water chemistry of a headwater alpine basin, Urumqi River,
 Tian Shan, China
SO Pp. 207-219 In Tonnessen, K. A., M. W. Williams, and M. Tranter (eds.).
 Biogeochemistry of Seasonally Snow Covered Basins. International
 Association of Hydrological Sciences, Wallingford, UK, IAHS-AIHS
 Publication no. 228. 465 pp.
DE NWTLTE
2000
R
; China
; hydrology
; hydrochemistry
; ionic pulse
; carbonic acid
; calcium
; aeolian deposition
; snowmelt
AB Hydrologic and hydrochemical measurements were conducted from May to 
 September 1991 in the Dry Cirque catchment, a seasonally snow-covered 
 alpine basin at the headwaters of the Urumqi River. Solute concentrations 
 in streamwater were generally highest at the initiation of snowmelt and 
 then declined through the melt season and into summer, then increased as 
 the contribution of baseflow to stream discharge increased. The snowpack 
 was sampled for chemical content during maximum snow accumulation in May 
 1992 to investigate the role of an ionic pulse and dissolution of aeolian 
 particles to stream water chemistry. At the initiation of snowmelt, ionic
 concentrations in snow were generally higher by a factor of four close to 
 the ground compared to the top of the snowpack, consistent with the release 
 of solutes from the snowpack in the form of an ionic pulse. Maximum 
 concentrations of HCO3- and Ca2+ in the snowpack were near 400 ueq/L and 
 associated with visibly dirty ice lens, indicating that dissolution of 
 aeolian particles in snow was a major source of these solutes. The release
 of solutes from the snowpack influenced stream chemistry during snowmelt 
 runoff, with aeolian deposition and an ionic pulse potentially important 
 sources of solutes in stream flow.
$
CL 1562
AU Liu, F.
; Williams, M.W.
; Ackerman, T.M.
DT 2002
TI Application of XTOP_PRMS Model in Green Lakes Valley, Colorado Front Range: Runoff Simulation and Flowpath Identification
SO 2002 Western Snow Conference Proceedings
DE NWTLTER
; conference proceedings
AB None.
$
CL1554
AU Liu, F.
; Williams, M.W.
; Caine, N.
DT 2004
TI Source waters and flow paths in an alpine catchment, Colorado Front Range, United States
SO  Water Resources Research vol. 40 
DE NWTLTER
; alpine catchment
; end-member mixing analysis
; flow paths
; mixing model
; source waters
AB Source waters and flow paths of streamflow draining high-elevation catchments of the Colorado Rocky Mountains were determined using isotopic and geochemical tracers during the 1996 snowmelt runoff season at two subcatchments of the Green Lakes Valley, Colorado Front Range. A two-component hydrograph separation using d 18 O indicates that new water dominated (82 ± 6%) streamflow at the 8-ha Martinelli catchment and old water dominated (64 ± 2%) at the 225-ha Green Lake 4 (GL4) catchment. Snowmelt became isotopically enriched as the melt season progressed, complicating the interpretation of source water models. Thus old water may be underestimated if the temporal variation in d 18 O of snowmelt is ignored or extrapolated from point measurements to the catchment. Two-component hydrograph separations for unreacted and reacted waters using a single geochemical tracer were not always meaningful.  Three-component hydrograph separations using end-member mixing analysis indicated that subsurface flow contributed more than two thirds to the streamflow at both catchments. Talus fields contributed more than 40% of the total discharge during summer at the GL4 catchment. A conceptual model was established for flow generation based on these results. It is suggested that surface water and groundwater interactions are much more important to the quantity and quality of surface water in high-elevation catchments than previously thought.
$
CL 0559e
AU Liu, S.C.
; Trainer, M.
; Fehsenfeld, F.C.
; Parrish, D.D.
; Williams, E.J.
; Fahey, D.W.
; Hubler, G.
; Murphy, P.C.
DT 1987
TI Ozone production in the rural troposphere and the implications for regional
 and global ozone distributions
SO Journal of Geophysical Research 92:4191-4207
DE article
; Atmospheric Science
; C-1
; atmospheric chemistry
; climate change
; ozone
AB None
$
CL 0559d
AU Liu, S.C.
DT 1985
TI Theoretical aeronomy program
SO In: Aeronomy Laboratory Annual Report - Fiscal Year 1985. Boulder, Colorado:
 United States Department of Commerce, National Oceanic and Atmospheric
 Administration, Environmental Research Laboratories, 30-38
DE Technical Report
; Atmospheric Sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0559b
AU Liu, S.C.
DT 1983
TI Theoretical aeronomy program
SO In: Aeronomy Laboratory Annual Report - Fiscal Year 1983. Boulder, Colorado:
 United States Department of Commerce, National Oceanic and Atmospheric
 Administration, Environmental Research Laboratories, 1-10
DE Technical Report
; Atmospheric Sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0559c
AU Liu, S.C.
DT 1984
TI Theoretical aeronomy program
SO In: Aeronomy Laboratory Annual Report - Fiscal Year 1984. Boulder, Colorado:
 United States Department of Commerce, National Oceanic and Atmospheric
 Administration, Environmental Research Laboratories, 1-11
DE Technical Report
; Atmospheric Sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0560a
AU Lorenz, D.C.
DT 1985
TI The effects of trampling on subalpine habitats in the Colorado Front Range:
 an experimental approach
SO M.S. thesis, University of Colorado, Boulder, 135 pp.
DE thesis
; ecology
; management
; University of Colorado
; Mountain Research Station
; conifers
; disturbance
; soil
; recovery
AB None
$
CL 0565
AU Losleben, M.
; Halfpenny, J.
; Ingraham, K.
DT 1984
TI Climate of alpine tundra, Front Range, Colorado
SO Abstracts and Program, International Snow Science Workshop: A Merging of
 Theory and Practice. Aspen, Colorado. October 24-27, 1984. 45. Abstract
DE Abstract
; Climatology
; Long-Term Ecological Research Program
; Mountain Research Station - Affiliation
; D-1 Climate Station
; Insolation
; Precipitation
; Wind
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0563a
AU Losleben, M.V.
DT 1986
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado -
 1985
SO University of Colorado Long-Term Ecological Research Data Report 86/1. 29 pp
DE Data Report
; Climatology
; Long-Term Ecological Research Program
; C-1 Climate Station
; D-1 Climate Station
; Saddle (Niwot Ridge)
; Climate - Data Included
AB None
$
CL 0564
AU Losleben, M.V.
; Eccles, M.
DT 1984
TI Front Range Climatological Program, Colorado
SO New Mexico Journal of Science, 24(1):35. Abstract
DE Abstract
; Climatology
; Long-Term Ecological Research Program
; Mountain Research Station - Affiliation
; Saddle, Niwot Ridge
; A-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0562
AU Losleben, M.V.
DT 1984
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado
 -1983
SO University of Colorado Long-Term Ecological Research Data Report, 84/3. 28
 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; C-1 Climate Station
; D-1 Climate Station
; Saddle, Niwot Ridge
; Climate - Data Included
; Insolation
; Precipitation
; Wind
; Temperature
AB None
$
CL 0566
AU Losleben, M.V.
; Halfpenny, J.C.
; Ingraham, K.P.
DT 1984
TI Climate of alpine tundra, Front Range, Colorado
SO New Mexico Journal of Science, 24(1):46. Abstract
DE Abstract
; Climatology
; Long-Term Ecological Research Program
; Mountain Research Station - Affiliation
; D-1 Climate Station
; Insolation
; Precipitation
; Wind
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0563
AU Losleben, M.V.
DT 1985
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado
 -1984
SO University of Colorado Long-Term Ecological Research Data Report, 85/3. 29
 pp.
DE Data report
; Climatology
; Institute of Arctic and Alpine Research
; Long-Term Ecological Research Program
; C-1 Climate Station
; D-1 Climate Station
; Saddle, Niwot Ridge
; Climate - Data Included
; Insolation
; Precipitation
; Wind
; Temperature
AB None
$
CL 1443    
AU Losleben, M.V.
DT 2000
TI Snowpack, ENSO, and atmospheric cirulation on the Colorado Front Range
SO In Proc
2000
eedings of the 16th Annual Pacific Climate Workshop, Technical Report 65 of the Interagency Ecological
 Program for Sacramento-San Joaquin Delta
DE None
AB None
$
CL 1396 
AU Losleben, M.V.
DT 2000
TI Snowpack, ENSO, and atmospheric circulation on the Colorado Front Range 
SO In Proceedings of the 16th annual Pacific Climate Workshop, Technical 
   Report 65 of the Interagency Ecological program for the Sacramento-San 
   Joaquin Delta.
DE None
AB None
$
CL 0561
AU Losleben, M.V.
DT 1983
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado,
 1970-1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/10. 193
 pp.
DE Data report
; Climatology
; Long-Term Ecological Research Program
; Mountain Research Station - Affiliation
; Saddle, Niwot Ridge
; A-1 Climate Station
; Climate - Data Included
; Climate - Discussion of
; Insolation
; Precipitation
; Wind
; Temperature
AB None
$
CL 0563e
AU Losleben, M.V.
DT 1991
TI Temporal variation of climatically important anthropogenic trace gas
 concentrations at a subalpine site, Front Range, Colorado
SO M.S. thesis, University of Colorado Boulder, 121 pp.
DE thesis
; atmospheric science
; NOAA - Climate Monitoring and Diagnostics Laboratory
; Long-Term Ecological Research Program
; C-1
; Atmospheric chemistry
; anthropogenic
; NWTLTER
AB None
$
CL 0563b
AU Losleben, M.V.
DT 1987
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado 1986
SO University of Colorado Long-Term Ecological Research Data Report 87/8. 40 pp
DE Data Report
; Climatology
; Long-Term Ecological Research Program
; D-1 Climate Station
; C-1 Climate Station
; Saddle (Niwot Ridge)
; Climate - Data Included
AB None
$
CL 1372
AU Losleben, M.V.
; Pepin, N.
; Pedrick, S.
DT 2000
TI Relationships of precipitation chemistry, atmospheric circulation, and
 elevation at two sites on the Colorado Front Range
SO Atmospheric Environment 34:1723-1737
DE NWTLTER
; synoptic
; deposition
; indicies
; pH
; conductivity
AB The acidity and conductivity of precipitation at two sites located
east of the Continental Divide in the Front Range of Colorado is
examined for temporal trends, differences, and relationships to
atmospheric circulation patterns for a 14 yr period (1984-1997).
The elevationally lower station, Sugarloaf, is about 20 km west
of Boulder, CO, and closer to the Denver/Boulder urban corridor
than the higher site, Niwot, which lies 11.4 km west of Sugarloaf,
and 1000m higher in elevation. Key findings of this study are that 
Sugarloaf precipitation has the higher pH (less acidic) and
lower conductivity of the two sites, and that different circulation 
patterns are associated with different inter-site precipitation
characteristics: chemistry, amount, occurrence, and seasonal differences.
Circulation indices account for about one-fourth to one-third of the
variability in precipitation chemistry, and synoptic scale circulation
patterns are clearly different for extremely low versus extremely
high pH conditions at these two sites.
$
CL 0563c
AU Losleben, M.V.
DT 1988
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Data Report 88/3. 48 pp
DE Data Report
; Climatology
; Long-Term Ecological Research Program
; D-1 Climate Station
; C-1 Climate Station
; Saddle (Niwot Ridge)
; Climate - Data Included
AB None
$
CL 0563d
AU Losleben, M.V.
DT 1990
TI Climatological data from Niwot Ridge, East Slope, Front Range, Colorado -
 1989
SO University of Colorado Long-Term Ecological Research Data Report 90/1. 108
 pp
DE Data Report
; Data report
; Climatology
; Long-Term Ecological Research Program
; Climate - Data
AB None
$
CL 0567
AU Love, A.,
; Love, D.,
; Kapoor, B.M.
DT 1971
TI Cryotaxonomy of a century of Rocky Mountain orophytes
SO Arctic and Alpine Research, 3:139-165
DE Genetics
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Rocky Mountain National Park - Location
; Mount Evans and Guanella Pass Region
; Taxonomy & systematics
AB None
$
CL 0571
AU Love, D.
; McClellan, C.
; Gamow, I.
DT 1970
TI Coumarin and coumarin derivatives in various growth types of Engelmann
 spruce
SO Svensk Botanisk Tidskrift, 64:284-296
DE Biology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Biochemical
; C-1 Climate Station
; D-1 Climate Station
AB None
$
CL 0568
AU Love, D.
DT 1969
TI Papaver at high altitudes in the Rocky Mountains
SO Brittonia, 21(1):1-10
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Indian Peaks Region
AB None
$
CL 0570
AU Love, D.
DT 1971
TI Reflections around a mutilated tree
SO Biological Conservation, 3(4):274-278
DE Ecology
; Chronology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Demography
; Tree
AB None
$
CL 0572
AU Low, R.S.
DT 1982
TI Identification, classification, and quantification of wetlands in alpine and
 subalpine watershed
SO Journal Colorado-Wyoming Academy of Sciences, 13(1):12. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Watershed
; Community
; Diversity
AB None
$
CL 0573
AU Ludi, W.
DT 1961
TI Botanische Streifzuge durch die Rocky Mountains Nordamerikas
SO Veroffentlichungen der Geobotanischen Institutes, Rubel, Zurich, 32:217-236
DE Ecology
; Phytosociology
; Niwot Ridge
; Mount Evans and Guanella Pass Region
; Rocky Mountain National Park - Location
; Angiosperms
; Conifers
; Physiographic
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0574
AU Lullau, I.
DT 1974
TI Studien und Beobachtungen zum Landschaftsgefuge in der ostlichen Front
 Range, Colorado
SO Staatsarbeit in Geographie, Munster. 120 pp.
DE Thesis
; Ecology
; Niwot Ridge
; Mountain Research Station - Location
; Wind
; Physiographic
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0575
AU Luti, R.
DT 1953
TI Ecological features of the vegetation of a ridge in the montane forest of
 Boulder County, Colorado
SO M.S. thesis, University of Colorado, Boulder. 100 pp.
DE Thesis
; Ecology
; University of Colorado
; B-1 Climate Station
; Plant
AB None
$
CL 0579
AU Macior, L.W.
DT 1974
TI Pollination ecology of the Front Range of the Colorado Rocky Mountains
SO Melanderia, 15:1-59
DE Ecology
; Niwot Ridge
; Angiosperms
; Pollination
AB None
$
CL 0577
AU Macior, L.W.
DT 1970
TI The pollination ecology of Pedicularis in Colorado
SO American Journal of Botany, 57(6):716-728
DE Ecology
; Niwot Ridge
; Angiosperms
; Pollination
AB None
$
CL 0578
AU Macior, L.W.
DT 1971
TI Co-evolution of plants and animals--systematic insights from plant-animal
 interactions
SO Taxon, 20(1):17-28
DE Overview
; Ecology
; Niwot Ridge
; Taxonomy & systematics
; Rocky Mountain National Park - Location
; Plant
; Animals
AB None
$
CL 0576
AU Macior, L.W.
DT 1968
TI Pollination adaptation in Pedicularis groenlandica
SO American Journal of Botany, 55(8):927-932
DE Ecology
; Niwot Ridge
; Angiosperms
; Pollination
AB None
$
CL 0616
AU Mahaney, W.C.
; Fahey, B.D.
DT 1976
TI Quaternary soil stratigraphy of the Front Range, Colorado
SO In: Mahaney, W.C. (ed.), Quaternary Stratigraphy of North America.
 Stroudsburg, PA: Dowden, Hutchinson, Ross, 319-352
DE Stratigraphy
; Chronology
; Soil sciences
; Mountain Research Station - Affiliation
; Soil
; Indian Peaks Region
AB None
$
CL 0609
AU Mahaney, W.C.
DT 1970
TI Soil genesis on deposits of Neoglacial and late Pleistocene age in the
 Indian Peaks of the Colorado Front Range
SO Ph.D. dissertation,  University of Colorado, Boulder. 246 pp.
DE Dissertation
; Geomorphology
; Chronology
; Soil sciences
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Soil
AB None
$
CL 0611
AU Mahaney, W.C.
DT 1972
TI Audubon: new name for Colorado Front Range Neoglacial deposits, formerly
 called "Arikaree."
SO Arctic and Alpine Research,
2000
 4:355-357
DE Geomorphology
; Chronology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Periglacial
; Glacier
AB None
$
CL 0614
AU Mahaney, W.C.
DT 1973
TI Neoglacial chronology of the Fourth of July Cirque, central Colorado Front
 Range: reply
SO Geological Society of America Bulletin, 84:3767-3772
DE Geomorphology
; Chronology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Periglacial
; Glacier
AB None
$
CL 0615
AU Mahaney, W.C.
DT 1974
TI Soil stratigraphy and genesis of Neoglacial deposits in the Arapaho and
 Henderson Cirques, Central Colorado Front Range
SO In: Mahaney, W.C. (ed.), Quaternary Environments: Proceedings of a
 Symposium. Geographical Monographs 5. Toronto: York University, 197-240
DE Stratigraphy
; Chronology
; Soil sciences
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Soil
AB None
$
CL 0610
AU Mahaney, W.C.
DT 1971
TI Note on the "Arikaree Stade" of the Rocky Mountains Neoglacial
SO Journal of Glaciology, 10(58):143-144
DE Geomorphology
; Chronology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Periglacial
; Glacier
AB None
$
CL 0617a
AU Mahaney, W.C.
; Fahey, B.D.
DT 1988
TI Extractable Fe and Al in late Pleistocene and Holocene paleosols on Niwot
 Ridge, Colorado Front Range
SO Catena, 15:17-26
DE Journal
; Soil Sciences
; Sedimentology
; Stratigraphy
; Niwot Ridge
; Soils
; Chemistry
; Paleoecology
AB None
$
CL 0613
AU Mahaney, W.C.
DT 1973
TI Neoglacial chronology in the Fourth of July Cirque, central Colorado Front
 Range
SO Geological Society of America Bulletin, 84:161-170
DE Geomorphology
; Chronology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Periglacial
; Glacier
AB None
$
CL 0612
AU Mahaney, W.C.
DT 1972
TI Reinterpretation of the Neoglacial chronology of the central Colorado Front
 Range
SO In: Miller, M.M. (ed.), Proceedings, Arctic and Mountain Environments
 Symposium, April 22-23, East Lansing, Michigan: Michigan State University
DE Geomorphology
; Chronology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Periglacial
; Glacier
AB None
$
CL 0620
AU Mancinelli, R.L.
DT 1984
TI Population dynamics of alpine tundra soil bacteria, Niwot Ridge, Colorado
 Front Range, Colorado, U.S.A.
SO Arctic and Alpine Research, 16:185-192
DE Microbiology
; Long-Term Ecological Research Program
; Niwot Ridge
; Climate - Discussion of
; Community
; Demography
; Phenological (seasonal)
; Decomposition
; NWTLTER
AB None
$
CL 0622
AU Mancinelli, R.L.
; Shulls, W.A.
DT 1983
TI Population dynamics of soil bacteria from Niwot Ridge, 1981-1982
SO University of Colorado Long-Term Ecological Research Data Report, 83/5. 13
 pp.
DE Data report
; Microbiology
; Long-Term Ecological Research Program
; Niwot Ridge
; Climate - Discussion of
; Community
; Demography
; Phenological (seasonal)
; Decomposition
AB None
$
CL 0602a
AU Mancinelli, R.L.
DT 1986
TI Alpine tundra soil bacterial responses to increased soil loading rates of
 acid precipitation, nitrate, and sulfate, Front Range, Colorado, USA
SO Arctic and Alpine Research, 18(3):269-275
DE Journal
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Boulder Watershed and Rainbow Lakes
; Bacteria
; Acid Deposition
; Precipitation
; Chemistry
; Pollution
; Soils
; Growth (Development)
; Population
; Productivity
; NWTLTER
AB None
$
CL 0623
AU Mancinelli, R.L.
; William, J.C.
DT 1984
TI Factors limiting cellulose decomposition in the alpine tundra
SO Abstracts of the Annual Meeting of the American Society for Microbiology,
 St. Louis. 187. Abstract
DE Abstract
; Microbiology
; Long-Term Ecological Research Program
; Niwot Ridge
; Climate - Discussion of
; Community
; Decomposition
AB None
$
CL 0621
AU Mancinelli, R.L.
; Keigley, R.B.
DT 1983
TI Effects of increases in soil loading rates of nitrate, nitrate/sulfate and
 acid rain on the alpine tundra soil bacterial community
SO Abstracts of the Annual Meeting of the American Society of Microbiology, New
 Orleans, Louisiana, 232. Abstract
DE Abstract
; Climatology
; Ecology
; Microbiology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Acid Deposition
; Community
; Nutrients
; Nitrogen
AB None
$
CL 0624
AU Mandics, P.A.
DT 1984
TI Advanced system for the interactive analysis and presentation of geophysical
 data
SO Proceedings of Oceans, September 10-12, 1984, 502-505
DE Technique
; Climatology
; NOAA - Profs
; C-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0625
AU Mandics, P.A.
; Brown, R.C.
DT 1985
TI When will the storm get here?
SO Research and Development, 27:72-77
DE Technique
; Climatology
; NOAA - Profs
; C-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0634
AU Marr, J.W.
; Clark, J.M.
; Osburn, W.S.
; Paddock, M.W.
DT 1968
TI Data on mountain environments. III. Front Range, Colorado, four climax
 regions, 1959-1965
SO University of Colorado Studies, Series in Biology, 29 181 pp.
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Climate - Data Included
; Climate - Discussion of
; Insolation
; Precipitation
; Wind
; Temperature
AB None
$
CL 0626
AU Marr, J.W.
DT 1958
TI Lee slope stands in the upper part of the forest-tundra ecotone on Niwot
 Ridge, Boulder County, Colorado
SO Journal Colorado-Wyoming Academy of Science, 4(10):41. Abstract
DE Abstract
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Conifers
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0631
AU Marr, J.W.
DT 1967
TI Data on mountain environments. I. Front Range, Colorado, sixteen sites,
 1952-1953
SO University of Colorado Studies, Series in Biology, 27. 110 pp.
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Climate - Data Included
; Climate - Discussion of
AB None
$
CL 0627
AU Marr, J.W.
DT 1959
TI Forms of tree islands in alpine tundra
SO Journal Colorado-Wyoming Academy of Science, 4(11):34. Abstract
DE Abstract
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Conifers
; Morphological
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0637
AU Marr, J.W.
; Marr, R.E.
DT 1973
TI Environment and phenology in the forest-tundra ecotone, Front Range,
 Colorado
SO Arctic and Alpine Research, 5(3, Pt. 2):A65-A66
DE Climatology
; Ecology
; University of Colorado
; C-1 Climate Station
; D-1 Climate Station
; Conifers
; Angiosperms
; Climate - Discussion of
; Phenological (seasonal)
AB None
$
CL 0635
AU Marr, J.W.
; Johnson, A.W.
; Osburn, W.S.
; Knorr, O.A.
DT 1968
TI Data on mountain environments. II. Front Range, Colorado, four climax
 regions, 1953-1958
SO University of Colorado Studies, Series in Biology, 28. 170 pp.
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Climate - Data Included
; Climate - Discussion of
; Insolation
; Precipitation
; Wind
; Temperature
AB None
$
CL 0633
AU Marr, J.W.
DT 1977
TI The development and movement of tree islands near the upper limit of tree
 growth in the Southern Rocky Mountains
SO Ecology, 58:1159-1164
DE Ecology
; University of Colorado
; Niwot Ridge
; Conifers
; Morphological
; Growth (Development)
; Movement
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0628
AU Marr, J.W.
DT 1961
TI Ecosystems of the east slope of the Front Range in Colorado
SO University of Colorado, Series in Biology, 8. 134 pp.
DE Ecology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Climate - Discussion of
; Community
; Ecosystem
AB None
$
CL 0639
AU Martinelli, M., Jr.
DT 1959
TI Some hydrologic aspects of alpine snowfields under summer conditions
SO Journal Geophysical Research, 64:451-455
DE Hydrology
; Mountain Research Station - Affiliation
; Niw
2000
ot Ridge
; Mount Evans and Guanella Pass Region
; Trail Ridge
; Rollins Pass and Tolland
; Rocky Mountain National Park - Location
; Snow
; Water
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0640
AU Martinelli, M., Jr.
DT 1964
TI Accumulation of snow in alpine areas of central Colorado and means of
 influencing it
SO Journal of Glaciology, 5(41):625-636
DE Hydrology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Saddle, Niwot Ridge
; Snow
; Wind
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0641
AU Martinelli, M., Jr.
DT 1967
TI Possibilities of snowpack management in alpine areas
SO In: Sopper, W.E. and Lull, H.W. (eds.), Proceedings of a Symposium on Forest
 Hydrology. Oxford: Pergamon Press, 225-231
DE Hydrology
; Management
; Mountain Research Station - Affiliation
; Niwot Ridge
; Snow
; Water
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0642
AU Martinelli, M., Jr.
DT 1973
TI Snow-fence experiments in alpine areas
SO Journal of Glaciology, 12(65):291-303. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 241-253
DE Hydrology
; Mount Evans and Guanella Pass Region
; Snow
; Boulder Watershed and Rainbow Lakes
AB None
$
CL1458
AU Mast, M.A
; Turk, T.K.
; Ingersoll, G.P.
; Clow, D.W.
; Kester, C.L.
DT 2001
TI Use of stable sulfer isotopes to identify sources of sulfate in Rocky Mountain snowpacks.  
SO Atmospheric Environment 35: 3303-3313
DE NWTLTER
AB None
$
CL 0644
AU May, D.E.
DT 1973
TI Models for predicting composition and production of alpine tundra vegetation
 from Niwot Ridge, Colorado
SO M.A. thesis, University of Colorado, Boulder. 99 pp.
DE Thesis
; Model
; Ecology
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Climate - Discussion of
; Community
; Productivity
; Angiosperms
AB None
$
CL 0649
AU May, D.E.
; Webber, P.J.
; May, T.A.
DT 1982
TI Success of transplanted alpine tundra plants on Niwot Ridge, Colorado
SO Journal of Applied Ecology 19(3):965-976
DE Ecology
; Management
; Long-Term Ecological Research Program
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Demography
; Revegetation
; NWTLTER
AB None
$
CL 0646
AU May, D.E.
DT 1976
TI The response of alpine tundra vegetation in Colorado to environmental
 variation
SO Ph.D. dissertation, University of Colorado, Boulder. 164 pp.
DE Dissertation
; Climatology
; Ecology
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Climate - Data Included
; Climate - Discussion of
; Morphological
; Phenological (seasonal)
; Growth (Development)
; Productivity
AB None
$
CL 0648
AU May, D.E.
; Webber, P.J.
DT 1982
TI Spatial and temporal variation of the vegetation and its productivity on
 Niwot Ridge, Colorado
SO In: Halfpenny, J.C. (ed.), Ecological studies in the Colorado alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37:35-62
DE Ecology
; Long-Term Ecological Research Program
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Climate - Data Included
; Climate - Discussion of
; Community
; Productivity
; NWTLTER
AB None
$
CL 0645
AU May, D.E.
DT 1974
TI Phenology and ecotypic variation in alpine tundra vegetation, Niwot Ridge,
 Colorado
SO Journal Colorado-Wyoming Academy of Sciences, 7(5):29-30. Abstract
DE Abstract
; Ecology
; Genetics
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Morphological
; Growth (Development)
; Phenological (seasonal)
AB None
$
CL 0647
AU May, D.E.
; Webber, P.J.
DT 1975
TI Summary of soil and plant canopy temperatures for the major vegetation types
 from Niwot Ridge, Colorado, for the period July 1972-October 1974.
SO U.S. Tundra Biome Data Report, 75-8. 129 pp.
DE Data report
; Climatology
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Temperature
; Climate - Data Included
; Climate - Discussion of
; Community
; Soil
AB None
$
CL 0650
AU May, D.E.
; Webber, P.J.
; May, T.A.
DT 1982
TI Success of transplanted alpine plants on Niwot Ridge, Colorado
SO In Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research Occasional Paper, 37:73-81
DE Ecology
; Stratigraphy
; Long-Term Ecological Research Program
; U.S. International Biological Programme
; Saddle, Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Demography
; Revegetation
; NWTLTER
AB None
$
CL 0657
AU May, T.A.
; Braun, C.E.
DT 1972
TI Weight dynamics of free-living white-tailed ptarmigan in Colorado
SO Journal Colorado-Wyoming Academy of Science, 7(2):70-71. Abstract
DE Abstract
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mammals
; Birds
; Bioenergetics
; Growth (Development)
AB None
$
CL 0656
AU May, T.A.
; Braun, C.E.
DT 1972
TI Seasonal foods of adult white-tailed ptarmigan in Colorado
SO Journal of Wildlife Management, 36:1180-1186. Reprinted in: Ives: J.D.
 (ed.), 1980: Geoecology of the Colorado Front Range. Boulder: Westview Press,
 478-484
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mammals
; Birds
; Food Habits
; Phenological (seasonal)
AB None
$
CL 0651
AU May, T.A.
DT 1970
TI Seasonal foods of white-tailed ptarmigan in Colorado
SO M.S. thesis, Colorado State University, Fort Collins. 55 pp.
DE Thesis
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mammals
; Birds
; Food Habits
AB None
$
CL 0654
AU May, T.A.
; Braun, C.E.
DT 1971
TI Seasonal foods of adult white-tailed ptarmigan in Colorado
SO Transactions Northwest Section of the Wildlife Society. Abstract
DE Abstract
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mammals
; Birds
; Food Habits
; Phenological (seasonal)
AB None
$
CL 0652
AU May, T.A.
DT 1975
TI Physiological ecology of white-tailed ptarmigan in Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 311 pp.
DE Dissertation
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mammals
; Birds
; Demography
; Food Habits
; Physiological
; Reproduction
; Habitat
AB None
$
CL 0653
AU May, T.A.
DT 1980
TI Animal ecology: overview
SO In: Ives, J.D. (ed.), Geoecology of the Colorado Front Range. Boulder:
 Westview Press, 430-435
DE Overview
; Ecology
; Animals
AB None
$
CL 0658
AU May, T.A.
; Braun, C.E.
DT 1973
TI Gizzard stones from adult white-tailed ptarmigan (Lagopus leucurus) in
 Colorado
SO Arctic and Alpine Research, 5:49-57
DE Biology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Mammals
; Birds
; Food Habits
; Physiological
AB None
$
CL 0580
AU McCauley, C.
DT 1958
TI Glaciers of the American Rocky Mountains
SO In: Geographic Study of Mountain Glaciation in the Northern Hemisphere.
 Report to the U.S. Army Quartermaster Research and Engineering Command Under
 Contract No. DA19-129-Qm-409. Study conducted by the Department of Exploration
 and Field Research, American Geographical Society, Project No. 7-83-03-008C.
 Part 3, Chapter 2
DE Technical report
; Glaciology
; Institute of Arctic and Alpine Research
; Indian Peaks Region
; Glacier
AB None
$
CL 0581
AU McCord, B.E.
DT 1982
TI Surficial deposits of the Indian Peaks Region, Colorado Front Range
SO M.A. thesis, University of Colorado, Boulder. 132 pp.
DE Thesis
; Geomorphology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Sediment
; Periglacial
AB None
$
CL 0582
AU McCown, B.H.
; Tieszen, L.L
DT 1972
TI A comparative investigation of periodic trends in carbohydrate and lipid
 levels in arctic and alpine plants
SO In: Bowen, S. (ed.), Proceedings 1972 Tundra Biome Symposium, Lake
 Wilderness Center, University of Washington, 3-5 April, 1972, U.S. IBP Tu
2000
ndra
 Biome, 40-40
DE Biology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Biochemical
AB None
$
CL 0582a
AU McKechnie, A.M.
TI Spatial and temporal use of food patches by the pika, Ochotona princeps
DT 1991
SO M.S. thesis, Colorado State University, Fort Collins, 74 pp.
DE thesis
; ecology
; Long-Term Ecological Research Program
; Saddle
; Lagomorphs
; food habits
; competition
; population
; NWTLTER
AB None
$
CL1471
AU McKnight, D.M.
; Kimball, B.A.
; Runkel, R.L.
DT 2001
TI pH dependence of iron photoreduction in a rocky mountain stream affected by acid mine drainage
SO HYDROLOGICAL PROCESSES 15 (10) pp1979-1992
DE mountain stream
; iron, hydrous metal oxides
; photoreduction
; reactive transport 
; REACTIVE SOLUTE TRANSPORT
; TRANSIENT STORAGE
; OXIDATION
; WATERS
; SIMULATION
; COLORADO
; SULFATE
AB The redox speciation of dissolved iron and the transport of iron in acidic, metal-enriched streams is controlled by precipitation and dissolution of iron hydroxides, by photoreduction of dissolved ferric iron and hydrous iron oxides, and by oxidation of the resulting dissolved ferrous iron. We examined the pH dependence of these processes in an acidic mine-drainage stream, St Kevin Gulch, Colorado, by experimentally increasing the pH of the stream from about 4.0 to 6.5 and following the downstream changes in iron species. We used a solute transport model with variable how to evaluate biogeochemical processes controlling downstream transport. We found that at pH 6.4 there was a rapid and large initial loss of ferrous iron concurrent with the precipitation of aluminium hydroxide. Below this reach, ferrous iron was conservative during the morning but there was a net downstream loss of ferrous iron around noon and in the afternoon. Calculation of net oxidation rates shows that the noontime loss rate was generally much faster than rates for the ferrous iron oxidation at pH 6 predicted by Singer and Stumm (1970. Science 167: 1121). The maintenance of ferrous iron concentrations in the morning is explained by the photoreduction of photoreactive ferric species, which are then depleted by noon. Copyright (C) 2001 John Wiley & Sons, Ltd. 
$
CL 0585
AU McNeely, R.
DT 1983
TI Preliminary physical data on Green Lakes 1-5, Front Range, Colorado
SO University of Colorado Long-Term Ecological Research Working Paper, 83/4. 34
 pp.
DE Data report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Altitude
; Lake
AB None
$
CL 0659
AU Meaney, C.
DT 1981
TI Rate and location of cheek marking by pika during the breeding season
SO Third International Symposium on Chemical Signals, Miami, Florida. Abstract
DE Abstract
; Behavior
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Lagomorphs
; Reproduction
AB None
$
CL 0659a
AU Meaney, C.A.
DT 1983
TI Olfactory communication of pikas (Ochotona princeps)
SO Ph.D. dissertation, University of Colorado, Boulder. 143 pp
DE Dissertation
; Ecology
; Long-Term Ecological Research Program
; Lagomorphs
; Niwot Ridge
; Behavior
AB None
$
CL 0661
AU Meierding, T.C.
DT 1982
TI Late Pleistocene glacial equilibrium-line altitudes in the Colorado Front
 Range: A comparison of methods
SO Quaternary Research, 18:289-310
DE Geomorphology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Soil
; Periglacial
; Climate - Discussion of
; Altitude
; Glaciology
AB None
$
CL 0662
AU Meierding, T.C.
; Birkeland, P.W.
DT 1980
TI Quaternary glaciation of Colorado
SO In: Kent, H.C. and Porter, K.W. (eds.), Rocky Mountain Association of
 Geologists - 1980 Symposium, Denver, Colorado, 165-173
DE Geomorphology
; Chronology
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Soil
; Periglacial
; Climate - Discussion of
; Glaciology
AB None
$
CL 1379
AU Meixner, T.
; Bales, R.C.
; Williams, M.W.
; Campbell, D.H.
; Baron, J.S.
DT 2000
TI Stream chemistry modeling of two watersheds in the Front Range, Colorado
SO Water Resourse Research 36:77-88
DE NWTLTER
; stream chemistry
AB We investigated the hydrologic, geochemical, and biochemical controls on 
 stream chemical composition on the Green Lakes Valley and Andrews Creek 
 watersheds using the alpine hydrochemical model (AHM).  Both sites had 
 comparable data sets from 1994 and 1996, including high-resolution spatial 
 data and high-frequency time series of hydrology, geochemistry, and meteorology.  
 The model of each watershed consisted of three terresrial subunits 
 (soil, talus, and rock), with the routing between the subunits determined 
 by spatial land cover data.  Using 1994 data for model calibration and 1996 
 data for evaluation, AHM captured the dominant processes and successfully 
 simulated daily stream chemical composition on both watersheds.  These results 
 confirm our procedure of using spatial and site-specific field and laboratory 
 data to generate an initial catchment model and then calibrating the model to 
 calculate effective parameters for unmeasured processes. A net source of 
 nitrogen was identified in the Andrews Creek watershed during the spring 
 snowmelt period, whereas nitrogen was immobilized in the Green Lakes Valley.  
 This difference iwas most likely due to the larger and more dominant area of 
 talus in the Andrews Creek watershed.  Our results aslo indicate that routing 
 of snowmelt through either soil or talus material is suffiecient for retention 
 of and release of base cations but that N retention is more important on areas 
 mapped as soil.  Owing to the larger ionic pulse and larger fraction of surface 
 runoff the Green Lakes Valley was more sensitive to a doubling of wet deposition 
 chemistry than the Andrews Creek watershed. 
$
CL1457
AU Meloche, C.G.
; Diggle, P.K.
DT 2001
TI Preformation, architectural complexity, and developmental flexibility in Acomastylis rossi (Rosaceae)
SO American Journal of Botany v.88 pp 908-991 
DE NWTLTER
AB None
$
CL 1516
AU Meloche, C.G. 
; Diggle, P.K. 
DT 2003
TI The pattern of carbon allocation supporting growth of preformed shoot primoridia in Acomastylis rossii.   
SO American Journal of Botany v. 90 pp. 1313-1320
DE NWTLTER
; Acomastylis rossii
; carbon allocation
; labeled carbon pulse chase experiment
; preformation
; Rosaceae
; resource allocation
; southern Rockies
; USA
AB Extreme preformation, the initiation of leaves or inflorescences more than 1 yr before maturation and function, is common in arctic and alpine habitats. This extended pattern of development provides a potential means to alleviate an apparent asynchrony between carbon supplied by photosynthesis in the summer and carbon demanded by growth in the spring. Allocation of resources to preforming organs has not been studied in herbs with multi-year patterns of preformation. Acomastylis rossii (Rosaceae) in the southern Rockies initiates leaves and inflorescences 2 yr prior to their maturation and function. Allocation to preforming organs in A. rossii was Studied by means of a labeled carbon pulse chase experiment. During the summer, carbon is allocated directly to preforming organs and rhizomes front the mature leaves. Additional allocation of carbohydrate into preforming organs occurs in autumn after photosynthesis by mature leaves has ceased. Organ primordia initiated in the second year do not receive a substantial quantity of the labeled carbon from reserves stored in the rhizome the previous year. We conclude that concurrent photosynthesis is the primary source of carbon for preformation development.
$
CL 1322
AU Menounos, B.P.
DT 1996
TI A holocene, debris-flow chronology for an alpine catchment, Colorado
 Front Range.
SO M.S. thesis, University of Colorado, Boulder. 160 pp.
DE NWTLTER
; debris flow
; Holocene
; Sky Pond
AB None
$
CL 0663
AU Mericle, L.W.
; Mericle, R.P.
DT 1965
TI Biological discrimination of differences in natural background radiation
 levels
SO Radiation Botany, 5:475-492
DE Radioecology
; Atomic Energy Commission
; Mountain 
2000
Research Station - Location
; Hazards
; Plant
AB None
$
CL 0664
AU Mericle, L.W.
; Mericle, R.P.
DT 1965
TI Reassessing the biological role of background terrestrial radiation as a
 constituent of the natural environment
SO Health Physics, 11:1607-1620
DE Radioecology
; Atomic Energy Commission
; Mountain Research Station - Location
; Hazards
; Plant
AB None
$
CL 0665
AU Merritt, J.F.
DT 1976
TI Population ecology and energy relationships of small mammals of a Colorado
 subalpine forest
SO Ph.D. dissertation, University of Colorado, Boulder. 133 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Rodents
; Climate - Discussion of
; Demography
; Bioenergetics
; Conifers
AB None
$
CL 0668
AU Merritt, J.F.
; Merritt, J.M.
DT 1978
TI Population ecology and energy relationships of Clethrionomys gapperi in a
 Colorado subalpine forest
SO Journal of Mammology, 59:576-598
DE Ecology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Rodents
; Conifers
; Climate - Discussion of
; Demography
; Bioenergetics
AB None
$
CL 0667
AU Merritt, J.F.
DT 1984
TI Winter Ecology of Small Mammals
SO Carnegie Museum of Natural History, Pittsburgh, Special Publication, 10. 380
 pp.
DE Overview
; Ecology
; Mountain Research Station - Location
; Rodents
AB None
$
CL 0669a
AU Merritt, J.F.
; Merritt, J.M.
DT 1980
TI Population ecology of the deer mouse (Peromyscus maniculatus) in the Front
 Range of Colorado
SO Annals of Carnegie Museum, Carnegie Museum of Natural History, 49(7):113-130
DE Ecology
; University of Colorado
; Mountain Research Station - Location
; Rodents
; Demography
; Snow
; Food Habits
; Reproduction
AB None
$
CL 0669
AU Merritt, J.F.
; Merritt, J.M.
DT 1978
TI Seasonal home ranges and activity of small mammals of a Colorado subalpine
 forest
SO Acta Theriologica, 23:195-202
DE Behavior
; Ecology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Rodents
; Phenological (seasonal)
; Movement
AB None
$
CL 0664a
AU Merritt, J.F.
DT 1984
TI Growth patterns and seasonal thermogenesis of Peromyscus maniculatus
 inhabiting the Appalachian and Rocky Mountains of North America
SO Annals of the Carnegie Museum of Natural History, 53:527-548
DE article
; ecology
; Mountain Research Station
; rodents
; temperature
; bioenergetics
; biomass
; growth
; physiological
; thermoregulation
AB None
$
CL 0664b
AU Merritt, J.F.
DT 1985
TI Influence of snowcover on survival of Clethrionomys gapperi inhabiting the
 Appalachian and Rocky Mountains of North America
SO Acta Zoologica Fennica, 173:73-74
DE article
; ecology
; Mountain Research Station
; rodents
; snow
; bioenergetics
; biomass
; growth
; population
; thermoregulation
AB None
$
CL 0666
AU Merritt, J.F.
DT 1984
TI Growth patterns and seasonal thermogenesis of Clethriomys gapperi inhabiting
 the Appalachian and Rocky Mountains of North America
SO In: Merritt, J.F. (ed.), Winter Ecology of Small Mammals. Special
 Publication of Carnegie Museum of Natural History, 10:201-213
DE Ecology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Rodents
; Climate - Discussion of
; Bioenergetics
; Phenological (seasonal)
; Growth (Development)
; Thermoregulation
AB None
$
CL 1558
AU Meyer, A.F.
; Lipson, D.A.
; Schadt, C.W.
; Martin, A.P.
; Schmidt, S.K.
DT 2004
TI Molecular and metabolic characterization of cold tolerant, alpine soil Pseudomonas, sensu stricto
SO Appl. Environ. Microbiol. vol. 70 pp. 483-489
DE NWTLTER
AB None
$
CL 0724d
AU Michaels, P.S.
DT 1985
TI Basin division and snowmelt discharge in an alpine basin
SO In:  Proceedings of the 53rd Annual Western Snow Conference pp. 117-126
DE Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Watershed
; NWTLTER
AB None
$
CL 0670
AU Michaels, P.S.
DT 1984
TI Temporal and spatial analysis of the isothermal snowpack in an alpine
 environment
SO M.A. thesis, University of Colorado, Boulder. 99 pp.
DE Thesis
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Insolation
; Snow
; Climate - Discussion of
; NWTLTER
AB None
$
CL 0670a
AU Mihuc, T.
DT 1989
TI Aquatic macroinvertebrate life history and phenology in a Colorado alpine
 wetland (Green Lakes Valley, Colorado Front Range)
SO M.S. thesis, Oklahoma State University, Stillwater, OK, 58 pp.
DE thesis
; Long-Term Ecological Research Program
; Boulder City Watershed
; invertebrates
; watershed
; lake
; distribution
; population
; life history
; NWTLTER
AB None
$
CL 1246
AU Mihuc, T.
; Toetz, D.
DT 1994
TI Determination of diets of alpine aquatic insects using stable isotopes and
 gut analysis
SO American Midland Naturalist 131:146-155
DE NWTLTER
; gut analyses
; stable isotopes
; macroinvertebrates
; Green Lakes Valley
; Asynarchus curtus
; chironomid larvae
; functional feeding group
; aquatic insects
AB We used both traditional gut analyses and stable isotopes to determine the
 diets of macroinvertebrates from an alpine wetland at 3593 m (Colorado Front
 Range). The two methods agreed. The Trichopteran, Asynarchus curtus (Banks)
 consumed mostly detritus, while chironomid larvae consumed periphyton and/or
 detritus. Filamentous algae, however, were not consumed by any taxa studied.
 The value of combining both methods is illustrated for Orthocladius, which is
 shown to be more a generalist in its diet based on stable isotopes than a
 specialist based upon analysis of gut contents. The results suggest that the
 way an animal captures its food (functional feeding group) does not
 necessarily imply an obligate trophic status for it.
$
CL 1305
AU Mihuc, T.B.
; Toetz, D.W.
DT 1996
TI Phenology of aquatic macroinvertebrates in an alpine wetland.
SO Hydrobiologia 330: 131-136
DE NWTLTER
; macroinvertebrates
; phenology
; alpine
; wetland
; Asynarchus curtus
; Chironomidae
AB The temporal distribution of populations of aquatic macroinvertebrates
 have been extensively investigated in temperate arctic regions, but
 little information is available for alpine regions in North America.
 This paper describes phenology patters of the aquatic macroinvertebrates
 of a high elevation wetland (3593 m) in the Green Lakes Valley, Colorado 
 Front Range.
 Abundant taxa were Chironomide (primarily Orthocladius and the limnephilid
 trichopteran Asynarchus curtus (Banks)). Temperature patterns were related
 to the seasonal timing of life stages of most species. Phenology of most
 alpine aquatic macroinvertebrates appears to be controlled by seasonal
 climatic patterns, particularly temperature patterns. All chironomid species
 and Asynarchus curtus (Banks) had univoltine life cycles. Multi-year life
 cycles were not observed at this alpine site, although they have been
 observed at some arctic sites with colder temperature regimes that observed
 in this study.
$
CL1474
AU Miller, A.E.
; Bowman, W.D.
DT 2002
TI Variation in 15N natural abundance and nitrogen uptake traits among co-occurring alpine species: do species partition by nitrogen form?
SO Oecologia v. 130 pp. 609-616
DE None
AB None
$
CL 1492
AU Miller, A.E.
; Bowman, W.D.
DT 2003
TI Alpine plants show species-level differences in the uptake of organic and inorganic nitrogen
SO Plant and Soil v. 250 pp 283-292
DE NWTLTER
; ammonium
; glycine
; nitrate
; SEDGE KOBRESIA MYOSUROIDES
; AMINO-ACID
; TUNDRA COMMUNITIES
; NUTRIENT-UPTAKE
; SOIL
; GROWTH
; NITRATE
; AVAILABILITY
; ACQUISITION
; AMMONIUM
AB As an estimate of species-level differences in the capacity to take up different forms of N, we measured plant uptake of N-15-NH4+, N-15-NO3- and N-15, [1]-C-13 glycine within a set of herbaceous species collected from three alpine community types. Plants grown from cuttings in the greenhouse showed similar growth responses to th
2000
e three forms of N but varied in the capacity to take up NH4+, NO3- and glycine. Glycine uptake ranged from approximately 42% to greater than 100% of NH4+ uptake; however, four out of nine species showed significantly greater uptake of either NH4+ or NO3- than of glycine. Relative concentrations of exchangeable N at the sites of plant collection did not correspond with patterns of N uptake among species; instead, species from the same community varied widely in the capacity to take up NH4+, NO3-, and glycine, suggesting the potential for differentiation among species in resource (N) use.$
CL 0672
AU Miller, P.C.
; Stoner, W.A.
; Ehleringer, J.R.
DT 1978
TI Some aspects of water relations of arctic and alpine regions
SO In: Tieszen, L.L. (ed.), Vegetation and Production Ecology of an Alaskan
 Arctic Tundra, New York: Springer-Verlag, 343-369
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Water
; Bioenergetics
; Evapotranspiration
AB None
$
CL 0671
AU Millett, M.T.
DT 1956
TI Glaciation in the headwaters of Middle Boulder Creek
SO M.A. thesis, University of Colorado, Boulder. 38 pp.
DE Thesis
; Geomorphology
; Glaciology
; University of Colorado
; Indian Peaks Region
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0676
AU Minges, D.R.
DT 1966
TI Determination of the effect of topography, season, and stream type on
 precipitation distribution
SO M.S. thesis, University of Colorado. 58 pp.
DE Climatology
; A-1 Climate Station
; Altitude
; Precipitation
; Stream
; Water
AB None
$
CL 0677
AU Mitchell, J.D.
DT 1978
TI Evaluation and comparison of stream habitats and populations between
 greenback cutthroat and rainbow trout in the Rocky Mountains of Colorado
SO M.A. thesis, University of Colorado, Boulder. 53 pp.
DE Thesis
; Ecology
; Mountain Research Station - Affiliation
; Mountain Research Station - Location
; Fish
; Stream
; Distribution
; Habitat
AB None
$
CL 0679
AU Mitchell, W.W.
; McKendrick, J.D.
; Wooding, F.W.
DT 1973
TI Responses of arctic, boreal and alpine biotypes in reciprocal transplants
SO U.S. Tundra Biome Data Report, 73-6. 15 pp.
DE Ecology
; Management
; U.S. International Biological Programme
; Niwot Ridge
; Morphological
; Physiological
; Angiosperms
AB None
$
CL 0682
AU Mitton, J.B.
; Grant, M.C.
DT 1980
TI Observations on the ecology and evolution of quaking aspen, Populus
 tremuloides, in the Colorado Front Range
SO American Journal of Botany, 67:202-209
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Distribution
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0680
AU Mitton, J.B.
DT 1985
TI So grows the tree
SO Natural History, 1:58-65.
DE Ecology
; Genetics
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0681
AU Mitton, J.B.
; Andalora, R.
DT 1981
TI Genetic and morphological relationships between blue spruce, Picea pungens
 Engelm. and Engelmann spruce, Picea engelmannii Parry, in the Colorado Front
 Range
SO Canadian Journal of Botany, 59:2088-2094
DE Genetics
; Institute of Arctic and Alpine Research
; Mountain Research Station - Location
; Conifers
; Morphological
; Tree
AB None
$
CL 0683
AU Mitton, J.B.
; Grant, M.C.
DT 1984
TI Associations among protein heterozygosity, growth rate and developmental
 homeostasis
SO Annual Review of Ecology and Systematics, 15:479-499
DE Genetics
; Institute of Arctic and Alpine Research
; Mountain Research Station - Location
; Conifers
; Growth (Development)
; Tree
AB None
$
CL 0684
AU Mitton, J.B.
; Knowles, P.
; Sturgeon, K.B.
; Linhart, Y.B.
; Davis, M.
DT 1981
TI Associations between heterozygosity and growth rate variables in western
 forest trees
SO In: Conkle, M.T. (ed.), Isozymes of North American Forest Trees and Forest
 Insects. U.S. Department of Agriculture General Technical Report. PSW-48. 64
 pp.
DE Genetics
; Institute of Arctic and Alpine Research
; Mountain Research Station - Location
; Conifers
; Growth (Development)
; Tree
AB None
$
CL1478
AU Monson, R.K.
; Turnipseed, A.A.
; Sparks, J.P.
; Harley, P.C.
; Scott-Denton, L.E.
; Sparks, K.
; Huxman, T.E.
DT 2002
TI Carbon sequestration in a high-elevation, subalpine forest
SO Global Change Biology 8(5):459-478
DE None
AB We studied net ecosystem CO2 exchange (NEE) dynamics in a high-elevation, subalpine forest in Colorado, USA, over a two-year period. Annual carbon sequestration for the forest was 6.71 mol C m(-2) (80.5 g C m(-2) ) for the year between November 1, 1998 and October 31, 1999, and 4.80 mol C m(-2) (57.6 g C m(-2) ) for the year between November 1, 1999 and October 31, 2000. Despite its evergreen nature, the forest did not exhibit net CO2 uptake during the winter, even during periods of favourable weather. The largest fraction of annual carbon sequestration occurred in the early growing-season; during the first 30 days of both years. Reductions in the rate of carbon sequestration after the first 30 days were due to higher ecosystem respiration rates when mid-summer moisture was adequate (as in the first year of the study) or lower mid-day photosynthesis rates when mid-summer moisture was not adequate (as in the second year of the study). The lower annual rate of carbon sequestration during the second year of the study was due to lower rates of CO2 uptake during both the first 30 days of the growing season and the mid-summer months. The reduction in CO2 uptake during the first 30 days of the second year was due to an earlier-than-normal spring warm-up, which caused snow melt during a period when air temperatures were lower and atmospheric vapour pressure deficits were higher, compared to the first 30 days of the first year. The reduction in CO2 uptake during the mid-summer of the second year was due to an extended drought, which was accompanied by reduced latent heat exchange and increased sensible heat exchange. Day-to-day variation in the daily integrated NEE during the summers of both years was high, and was correlated with frequent convective storm clouds and concomitant variation in the photosynthetic photon flux density (PPFD). Carbon sequestration rates were highest when some cloud cover was present, which tended to 
diffuse the photosynthetic photon flux, compared to periods
with completely clear weather.
The results of this study are in contrast to those of other 
studies that have reported increased annual NEE during
years with earlier-than-normal spring warming. In the 
current study, the lower annual NEE during 2000, the year
with the earlier spring warm-up, was due to (1) coupling 
of the highest seasonal rates of carbon sequestration to the
spring climate, rather than the summer climate as in other 
forest ecosystems that have been studied, and (2) delivery
of snow melt water to the soil when the spring climate was 
cooler and the atmosphere drier than in years with a later
spring warm-up. Furthermore, the strong influence of mid-summer 
precipitation on CO2 uptake rates make it clear that water 
supplied by the spring snow melt is a seasonally limited 
resource, and summer rains are critical for sustaining high 
rates of annual carbon sequestration.
$
CL 1228
AU Monson, R.K.
; Grant, M.C.
; Jaeger, C.H.
; Schoettle, A.W.
DT 1992
TI Morphological causes for the retention of precipitation in the crowns of
 alpine plants
SO Environmental and Experimental Botany 32: 319-327
DE NWTLTER
; acid precipitation
; plant morphology
AB Studies were conducted on 27 species of alpine plants to test the hypothesis
 that structural characteristics of leaves have a predictable influence on the
 amount of moisture retained by a plant crown following a simulated rain event.
 The retention of precipitation in crowns has been previously demonstrated as
 one factor potentially contributing to the direct effects of acid rain on
 alpine plants. The results of this study demonstrate that a significant share
 of the amount of water retained could be e
2000
xplained by general structural
 features of leaves and flowers common to all the diverse taxa studied. Water
 retained per unit leaf area was best explained by pubescence rank, number of
 leaves, petiole base width, flower mass, flower wettability and petiole base
 angle. Water retained per unit mass was best explained by pubescence ranking,
 number of leaves, petiole base width, leaf area, flower wettability, flower
 mass and number of flowers.
$
CL 1413
AU Monson, R.K.
; Mullen, R.B.
; Bowman, W.D.
DT 2001
TI Plant nutrient relations
SO In: Bowman, W.D. and T.R. Seastedt (eds). Structure and function of an alpine ecosystem: Niwot Ridge, Colorado. Oxford University Press
DE None
AB None
$
CL 0685
AU Mooney, H.A.
; Billings, W.D.
DT 1961
TI Comparative physiological ecology of arctic and alpine populations of Oxyria
 digyna
SO Ecological Monographs, 31:1-29
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Physiological
; Growth (Development)
; Metabolism
; Photosynthesis
AB None
$
CL 0686
AU Moore, R.J.
; Ehleringer, J.
; Miller, P.C.
; Caldwell, M.M.
; Tieszen, L.L.
DT 1973
TI Gas exchange studies of four alpine tundra species at Niwot Ridge, Colorado
SO In: Bliss, L.C. and Wielgolaski, F.E. (eds.), Proceedings of the Conference
 on Primary Production and Production Processes, Tundra Biome. Dublin, Ireland,
 April 1973. Stockholm: IBP Tundra Biome Steering Committee, 211-218
DE Biology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Carbon Dioxide
; Physiological
AB None
$
CL 0687
AU Morey, C.A.
DT 1927
TI Glaciation in the Arapahoe and Albion Valleys
SO M.S. thesis, University of Colorado, Boulder. 62 pp.
DE Glaciology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
AB None
$   
CL 1345
AU Mullen, R.B.
; Schmidt, S.K.
; Jaeger, C.H.
DT 1998
TI Nitrogen uptake during snowmelt by the snow buttercup, Rannunculus adoneus.
SO Arctic and Alpine Research 30:121-125
DE NWTLTER
; Rannunculus adoneus
; nitrogen
AB Seasonal patterns of nitrogen (N) uptake were measured to assess the ability of the alpine herb 
 Ranunculus adoneus to utilize the flush of N during snowmelt in alpine tundra ecosystem.  
 Development of mycorrhizal and dark septate fungi were also monitored within the roots of this snowbed 
 plant in order to determine the role of these fungi in N acquisition.  In addition, soil temperature, 
 moisture, and inorganic N levels were measured to determine possible influences of edaphic factors on 
 plant N uptake.  In contrast to P uptake, which occurrs late in the growing season and corresponds with 
 arbuscular mycorrhizal (AM) development, N uptake occurred very early in the growing season before new 
 roots and active AM fungal structures were formed.  Soils at this time were cold and wet and NH4+ was 
 the predominant form of inorganic nitrogen. Our data indicate that R. adoneus is able to take advantage 
 of the early season flush of N by utilizing the previous year's root system which is heavily infected 
 with a dark septate fungusily infected with a dark septate fungus.  Given the high density of R. adoneus 
 plants (135 plants per m2) in the snowbed system, they are a significant sink (ca. 0.5 g N per m2) for 
 nitrogen released from within or beneath the alpine snowpack.
$
CL 1273
AU Mullen, R.B.
DT 1995
TI Fungal endophytes in the alpine buttercup Ranunculus adoneus:
 Implications for nutrient cycling in alpine systems
SO Ph.D. dissertation, University of Colorado, Boulder. 122 pp.
DE NWTLTER
; Ranunculus adoneus
; nutrient cycling
; Niwot Ridge
; mycorrhizal fungi
; phosphorus
; edaphic factors
; nitrogen
; biogeochemistry
AB Ranunculus adoneus (the snow buttercup), a perennial herb
 common in snowbed areas of alpine tundra in the Rocky 
 Mountains is remarkable in its ability to emerge through snow 
 in full bloom. In addition, its roots contain a myriad of 
 fungal inhabitants. The purpose of this research was to clarify 
 the role of mycorrhizal and other endophytic fungi in 
 phosphorus and nitrogen cycling in alpine tundra systems using 
 R. adoneus and its fungal symbionts as study organisms. 
 Phosphorus and nitrogen were chosen because they are the most 
 common limiting nutrients to plant growth in these systems. The 
 works consisted of 1) a field study of vesicular-arbuscular (VA) 
 mycorrhizal development, plant phenology, plant nutrient uptake, 
 and environmental factors, and 2) laboratory experiments 
 involving nitrogen utilization and temperature tolerances of dark 
 septate fungi isolated from R. adoneus. Mycorrhizal development
 corresponded with phosphorus accumulation in R. adoneus.
 This accumulation occurred late in the growing season after
 seed set, when plants were producing new tissues for the
 next year and appears to allow the plants to bloom the
 next year when snowmelt begins. In contrast, R. adoneus 
 took up nitrogen (N) very early in the growing season 
 during snowmelt, when availability was high, new roots had
 not yet formed, and old roots contained high levels of a
 dark septate (DS) fungus. Since some fungal symbionts are
 known to translocate N to host plants, and not much is
 known about this fungus, including its nutritional
 capabilities, its ability to utilize various nitrogen
 sources over a range of temperatures was tested. Laboratory
 studies of 2 dark septate isolates from R. adoneus roots
 revealed that the fungi had the ability to take up and 
 grow on both organic and inorganic N at temperatures from
 0 degrees to -28 degrees Celsius. Kinetic analysis of
 uptake revealed that these fungi have a high affinity for
 amino acids at concentrations that exist in nature,
 especially at the lower temperatures. Thus, dark septate
 fungi could be an important sink for early season nitrogen
 in soil and also contribute to the nitrogen nutrition of
 R. adoneus.
$
CL 1238
AU Mullen, R.B.
; Schmidt, S.K.
DT 1993
TI Mycorrhizal infection, phosphorus uptake and phenology in Ranunculus
 adoneus: Implications for the functioning of mycorrhizae in alpine systems
SO Oecologia 94: 229-234
DE NWTLTER
; vesicular-arbuscular mycorrhizal fungi
; development
; phosphorus uptake
; Ranunculus adoneus
; Niwot Ridge Saddle
AB Phosphorus levels, phenology of roots and shoots, and development of
 vesicular arbuscular mycorrhizal (VAM) fungi were monitored for two years in
 natural populations of the perennial alpine herb, Ranunculus adoneus. The
 purpose of this study was to understand how phosphorus uptake relates to the
 phenology of R. adoneus and to ascertain whether arbusculus, fungal structures
 used for nutrient transfer, were present when maximum phosphorus accumulation
 was occurring. Arbuscules were only present for a few weeks during the growing
 season of R. adoneus and their presence corresponded with increased phosphorus
 accumulation in both the roots and shoots of R. adoneus. In addition,
 phosphorus accumulation and peaks in mycorrhizal development occurred well
 after plant reproduction and most plant growth had occurred. The late season
 accumulation of phosphorus by mycorrhizal roots of R. adoneus is stored for
 use during early season growth and flowering the following spring. In this way
 R. adoneus can flower before soils thaw and root or mycorrhizal nutrient
 uptake can occur.
$
CL1548
AU Nanus, L
; Campbell, D.H.
; Ingersoll, G.P.
; Clow, D.W.
; Mast, M.A.
DT 2003
TI Atmospheric deposition maps for the Rocky Mountains
SO Atmospheric Environment vol. 37 pp. 4881-4892
DE NWTDATA
; atmospheric deposition
; GIS
; kriging
; precipitation chemistry
; Rocky Mountains
AB Variability in atmospheric deposition across the Rocky Mountains is influenced by elevation, slope, aspect, and precipitation amount and by regional and local sources of air pollution. To improve estimates of deposition in mountainous regions, maps of average annual atmospheric deposition loadings of nitrate, sulfate, and acidity were developed for the Rocky Mountain
2000
s by using spatial statistics. A parameter-elevation regressions on independent slopes model (PRISM) was incorporated to account for variations in precipitation amount over mountainous regions. Chemical data were obtained from the National Atmospheric Deposition Program/National Trends Network and from annual snowpack surveys conducted by the US Geological Survey and National Park Service, in cooperation with other Federal, State and local agencies. Surface concentration maps were created by ordinary kriging in a geographic information system, using a local trend and mathematical model to estimate the spatial variance. Atmospheric deposition maps were constructed at l-km resolution by multiplying surface concentrations from the kriged grid and estimates of precipitation amount from the PRISM model. Maps indicate an increasing spatial trend in concentration and deposition of the modeled constituents, particularly nitrate and sulfate, from north to south throughout the Rocky Mountains and identify hot-spots of atmospheric deposition that result from combined local and regional sources of air pollution. Highest nitrate (2.5-3.0 kg/ha N) and sulfate (10.0-12.0 kg/ha SO4) deposition is found in northern Colorado. Published by Elsevier Ltd.$
CL 1521
AU Neff, J.C.
; Townsend, A.R.
; Gleixner, G.
; Lehman, S.J.
; Turnball, J. 
; Bowman, W.D.
DT 2002
TI Variable Effects of Nitrogen Additions on the Stability and Turnover of Soil Carbon
SO Nature v. 419 no. 6910 pp. 915-917
DE NWTLTER
; LEAF-LITTER DECOMPOSITION
; FOREST ECOSYSTEMS
; TEMPERATE FOREST
; STORAGE
; AVAILABILITY
; DEPOSITION
; DYNAMICS
; LIGNIN
; CYCLE
AB Soils contain the largest near-surface reservoir of terrestrial carbon(1) and so knowledge of the factors controlling soil carbon storage and turnover is essential for understanding the changing global carbon cycle. The influence of climate on decomposition of soil carbon has been well documented(2,3), but there remains considerable uncertainty in the potential response of soil carbon dynamics to the rapid global increase in reactive nitrogen (coming largely from agricultural fertilizers and fossil fuel combustion). Here, using C-14, C-13 and compound-specific analyses of soil carbon from long-term nitrogen fertilization plots, we show that nitrogen additions significantly accelerate decomposition of light soil carbon fractions (with decadal turnover times) while further stabilizing soil carbon compounds in heavier, mineral-associated fractions (with multidecadal to century lifetimes). Despite these changes in the dynamics of different soil pools, we observed no significant changes in bulk soil carbon, highlighting a limitation inherent to the still widely used single-pool approach to investigating soil carbon responses to changing environmental conditions. It remains to be seen if the effects observed here-caused by relatively high, short-term fertilizer additions-are similar to those arising from lower, long-term additions of nitrogen to natural ecosystems from atmospheric deposition, but our results suggest nonetheless that current models of terrestrial carbon cycling do not contain the mechanisms needed to capture the complex relationship between nitrogen availability and soil carbon storage.$
CL 1261
AU Neff, J.C.
; Bowman, W.D.
; Holland, E.A.
; Fisk, M.C.
; Schmidt, S.K.
DT 1994
TI Fluxes of nitrous oxide and methane from nitrogen-amended soils in
 a Colorado alpine ecosystem
SO Biogeochemistry 27:23-33
DE NWTLTER
; alpine
; fertilization
; trace gas
; methane
; nitrous oxide
; Niwot Ridge
AB In order to determine the effect of increased nitrogen inputs on
 fluxes of N2O and CH4 from alpine soils, we measured fluxes of these
 gases from fertilized and unfertilized soils in wet and dry alpine
 meadows. In the dry meadow, the addition of nitrogen resulted in a
 22-fold increase in N2O emissions, while in the wet meadow, we 
 observed a 45-fold increase in N2O emission rates. CH4 uptake in the 
 dry meadow was reduced 52% by fertilization; however, net CH4 
 production occurred in all of the wet meadow plots and emission rates
 were not significantly affected by fertilization. Net nitrification
 rates in the dry meadow were higher in fertilized plots than in non-
 fertilized plots throughout the growing season; net mineralization 
 rates in fertilized dry meadow plots were higher than those in non-
 fertilized plots during the latter half of the growing season.
$
CL 1559
AU Nemergut, D.R.
; Martin, A.P.
; Schmidt, S.K.
DT 2004
TI Integron diversity in heavy metal contaminated mine tailings and inferences about integron origin and evolution
SO Appl. Environ. Microbiol. vol. 70 pp. 1160-1168
DE NWTLTER
; PSEUDOMONAS-PSEUDOALCALIGENES JS45
; GRAM-NEGATIVE BACTERIA
; VIBRIO-CHOLERAE O1
; 16S RIBOSOMAL-RNA
; SUPER-INTEGRONS
; HYDROXYLAMINOBENZENE MUTASE
; PHYLOGENETIC INFERENCE
; ANTIBIOTIC-RESISTANCE
; ENVIRONMENTAL DNA
; ESCHERICHIA-COLI
AB Integrons are horizontal gene transfer (HGT) systems containing elements necessary for site-specific recombination and expression of foreign DNA. The overall phylogenetic distribution of integrons and range of genes that can be transferred by integrons are unknown. This report contains an exploration of integrons in an environmental microbial community and an investigation of integron evolution. First, using culture-independent techniques, we explored the diversity of integrons and integron-transferred genes in heavy-metal-contaminated mine tailings. Using degenerate primers, we amplified integron integrase genes from the tailings. We discovered 14 previously undescribed integrase genes, including six novel gene lineages. In addition, we found 11 novel gene cassettes in this sample. One of the gene cassettes that we sequenced is similar to a gene that codes for a step in a pathway for nitroaromatic catabolism, a group of compounds associated with mining activity. This suggests that integrons may be important for gene transfer in response to selective pressures other than the presence of antibiotics. We also investigated the evolution of integrons by statistically comparing the phylogenies of 16S rRNA and integrase genes from the same organisms, using sequences from GenBank and various sequencing projects. We found significant differences between the organismal (16S rRNA) and integrase trees, and we suggest that these differences may be due to HGT.
$
CL 0699
AU Nichols, H.
DT 1982
TI Review of late Quaternary history of vegetation and climate in the mountains
 of Colorado
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine.
 University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper, 37:27-33
DE Overview
; Paleoecology
; Long-Term Ecological Research Program
; Indian Peaks Region
; Conifers
; Angiosperms
; Climate - Discussion of
; Pollen
; Forest-Tundra Ecotone (Timberline)
; NWTLTER
AB None
$
CL 0700a
AU Noble, M.G.
; Butler, N.M.
DT 1988
TI The delayed colonization of suitable habitats by Nuphar luteum spp.
 polysepalum at high altitude in Colorado
SO Mountain Research Station, University of Colorado Natural History Paper 3, 4
 pp
DE Technical Report
; Ecology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Angiosperms
; Community
AB None
$
CL 0703
AU Norton, R.B.
; Roberts, J.M.
; Huebert, B.J.
DT 1983
TI Troposphere oxalate
SO Geophysical Research Letters, 10(7):517-520
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0700b
AU Norton, R.B.
DT 1986
TI Measurements of formate and acetate in precipitation at Niwot Ridge and
 Boulder, Colorado
SO Geophysical Research Letters, 12:769-772
DE article
; technique
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; precipitation
AB None
$
CL 1260
AU O'Lear, H.A.
; Seastedt, T.R.
DT 1994
TI Landscape patterns of litter decomposition in alpine tundra
SO Oecologia 99:95-101
DE NWTLTER
; alpine
; decomposition
; landscape lit
2000
ter
; microarthropods
; Saddle
AB A two-year study of the decomposition of alpine avens
 (Acomastylis rossii) foliage in alpine tundra of the Front Range of
 Colorado demonstrated a strong landscape-mediated effect on decay
 rates. Litter on sites with intermediate amounts of snowpack
 decayed more rapidly than litter on sites with larger or smaller
 amounts of snow. Annual decay constants (k-values) of this foliage
 ranged from -0.33 in dry tundra to -0.52 in moist tundra to -0.47
 in the wettest habitat. No site differences on mass loss of litter
 were detected until late winter-early spring of the first year of
 decomposition, when significantly faster decomposition was observed
 for litter beneath the snowpack. In spite of obvious landscape-
 related patterns in rates of litter decomposition, total micro-
 arthropod densities in the top 5 cm of soil did not differ among 
 habitats. However, the relative abundance of the oribatid and 
 prostigmatid mites did vary significantly across the landscape in
 relation to the moisture gradient. Oribatid mites comprised a
 greater proportion of the total mites in wetter areas. 
 Microarthropod densities and composition, as well as patterns of
 decomposition, were compared with previous alpine, as well as 
 arctic tundra, studies. The effects of soil invertebrates on 
 decomposition rates in the alpine was evaluated with a mushroom 
 litterbag decomposition experiment. Naphthalene was used to exclude 
 fauna from a subset of litterbags placed in mesic and xeric habitats. 
 Mushrooms without naphthalene additions decayed significantly faster 
 in the mesic sites. Densities of invertebrates were also greater on 
 mushrooms in these mesic sites. Mushrooms placed in xeric sites 
 generally lacked fauna. Thus, both the activities and the composition 
 of the detritus-based food web appear to change substantially across 
 the moisture gradient found in alpine tundra.
$
CL 0705
AU Oder, A.L.
DT 1932
TI Preliminary survey of the faunas and flora of a series of morainal lakes in
 the montane zone near Silver Lake, Colorado
SO M.A. thesis, University of Colorado, Boulder. 53 pp.
DE Thesis
; Fauna
; Flora
; Ecology
; History
; University of Colorado
; Niwot Ridge
; Invertebrates
; Lake
; Distribution
; Plankton
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0706
AU Olson, B.L.
DT 1969
TI An Archaic site in the Colorado Front Range
SO Journal Colorado-Wyoming Academy of Science, 6(2):43. Abstract
DE Abstract
; Archaeology
; Boulder Watershed and Rainbow Lakes
AB None
$
CL 0706a
AU Olyphant, G.A.
DT 1985
TI Topoclimate and the distribution of Neoglacial facies in the Indian Peaks
 section of the Front Range, Colorado, USA
SO Arctic and Alpine Research, 17(1):69-78
DE Model
; Climatology
; Paleoecology
; Geomorphology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Climate - Discussion of
; Insolation
; Snow
; Precipitation
; Wind
; Topography
; NWTLTER
AB None
$
CL 0706c
AU Olyphant, G.A.
; Isard, S.A.
DT 1987
TI Some characteristic of turbulent transfer over alpine surfaces during the
 snowmelt-growing season: Niwot Ridge, Front Range, Colorado, USA
SO Arctic and Alpine Research, 19(3):261-269
DE Journal
; Climatology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Wind
; Climate - Discussion of
; Snow
; Growth (Development)
; NWTLTER
AB None
$
CL 0706b
AU Olyphant, G.A.
DT 1986
TI The components of incoming radiation within a midlatitude alpine watershed
 during the snowmelt season
SO Arctic and Alpine Research, 18(2):163-169
DE Journal
; Climatology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Altitude
; Latitude
; Climate - Discussion of
; Insolation
; NWTLTER
AB None
$
CL 0706ba
AU Olyphant, G.A.
; Isard, S.A.
DT 1988
TI The role of advection in the energy balance of late-lying snow-fields: Niwot
 Ridge, Front Range, Colorado
SO Water Resources Research, 24:1962-1968
DE article
; hydrology
; climatology
; Long-Term Ecological Research Program
; Niwot Ridge
; Boulder City Watershed
; energy budget
; snow
; NWTLTER
AB None
$
CL 0715
AU Osburn, W.S.
; Benedict, J.B.
; Corte, A.E.
DT 1965
TI Frost phenomena, patterned ground, and ecology on Niwot Ridge
SO In: Schultz, C.B. and Smith, H.T.U. (eds.), Guidebook for One-Day Field
 Conferences, Boulder Area, Colorado, International Association for Quaternary
 Research, VII Congress, 21-26
DE Ecology
; Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Frost
; Permafrost
; Climate - Discussion of
; Institute of Arctic and Alpine Research
; Guide
AB None
$
CL 0713
AU Osburn, W.S.
DT 1967
TI Ecological concentration of nuclear fallout in a Colorado mountain watershed
SO In: Aberg, B. and Hungate, F.P. (eds.), Radioecological Concentration
 Processes. New York: Pergamon Press, 675-709
DE Ecology
; Radioecology
; Atomic Energy Commission
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Conifers
; Angiosperms
; Mammals
; Lake
; Snow
; Soil
; Stream
; Watershed
; Reproduction
AB None
$
CL 0712
AU Osburn, W.S.
DT 1966
TI Radioecology of the Front Range
SO Terminal Report on U.S. Atomic Energy Commission Contract No. At (11-1-1191)
 with the University of Colorado, Boulder. 118 pp.
DE Overview
; Ecology
; Radioecology
; Atomic Energy Commission
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Institute of Arctic and Alpine Research
AB None
$
CL 0708
AU Osburn, W.S., Jr.
DT 1958
TI Characteristics of the Kobresia bellardi meadow stand ecosystem in the Front
 Range, Colorado
SO Journal Colorado-Wyoming Academy of Sciences, 4(10):38-39. Abstract
DE Abstract
; Ecology
; Atomic Energy Commission
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Soil
; Climate - Discussion of
AB None
$
CL 0710
AU Osburn, W.S., Jr.
DT 1963
TI The dynamics of fallout distribution in a Colorado alpine tundra snow
 accumulation ecosystem
SO In: Schults, V. and Klement, A.W. (eds.), Radioecology. New York: Reinhold
 Publishing Company, 51-71
DE Ecology
; Radioecology
; Atomic Energy Commission
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Conifers
; Angiosperms
; Mammals
; Lake
; Snow
; Soil
; Stream
; Watershed
; Reproduction
AB None
$
CL 0709
AU Osburn, W.S., Jr.
DT 1958
TI Ecology of winter snow-free areas of the alpine tundra of Niwot Ridge,
 Boulder County, Colorado
SO Ph.D. dissertation, University of Colorado. 77 pp.
DE Dissertation
; Ecology
; Atomic Energy Commission
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Rodents
; Snow
; Soil
; Climate - Data Included
; Climate - Discussion of
; Community
; Distribution
AB None
$
CL 0714
AU Osburn, W.S., Jr.
DT 1969
TI Accountability of nuclear fallout deposited in a Colorado high mountain bog
SO In: Nelson, D.G. and Evans, F.C. (eds.), Symposium on radioecology, US AEC
 Report, CONF-670503, 578-86. New York: US Atomic Energy Commission Operations
 Office
DE Ecology
; Radioecology
; Atomic Energy Commission
; Boulder Watershed and Rainbow Lakes
; Angiosperms
; Precipitation
; Snow
AB None
$
CL 0711
AU Osburn, W.S., Jr.
DT 1963
TI Influence of four Rocky Mountain regional environments on pea plants grown
 from irradiated seeds
SO In: Schultz, V. and Klement, A.W., Jr. (eds.), Radioecology. New York:
 Reinhold Publishing Company, 319-324
DE Ecology
; Radioecology
; Atomic Energy Commission
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Angiosperms
; Climate - Discussion of
; Seed
AB None
$
CL 0718
AU Outcalt, S.I.
; Benedict, J.B.
DT 1965
TI Photointerpretation of two types of rock glacier in the Colorado Front
 Range, U.S.A.
SO Journal of Glaciology, 5(42):849-856
DE Geomorphology
; Remote sensing
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Periglacial
AB None
$
CL 0719
AU Outcalt, S.I.
; MacPhail, D
2000
.D.
DT 1965
TI A survey of Neoglaciation in the Front Range of Colorado
SO University of Colorado Studies, Series in Earth Science, 4. 124 pp.
 Summarized in: Ives, J.D. (ed.), 1980: Geoecology of the Colorado Front Range.
 Boulder: Westview Press, 203-208
DE Geomorphology
; Chronology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Dating - Radiocarbon and Other
; Periglacial
AB None
$
CL 0721
AU Paddock, M.W.
DT 1959
TI Weather types of the east slope of the Colorado Front Range (abstracted)
SO Attachment VIIF to Technical Progress Report of the Institute of Arctic and
 Alpine Research to the United States Atomic Energy Commission, Contract No.
 AT(11-1)435. 4 pp.
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0720
AU Paddock, M.W.
DT 1959
TI Some precipitation patterns in the Colorado Front Range as related to
 elevations and weather types
SO Journal Colorado-Wyoming Academy of Sciences, 4(11):38. Abstract
DE Climatology
; Institute of Arctic and Alpine Research
; A-1 Climate Station
; Altitude
; Precipitation
AB None
$
CL 0722
AU Paddock, M.W.
DT 1961
TI The food habits of the pika, Ochotona princeps saxatilis Bangs
SO M.A. thesis, University of Colorado. 81 pp.
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Lagomorphs
; Angiosperms
; Food Habits
AB None
$
CL 0724
AU Paddock, M.W.
DT 1964
TI Science Lodge conference on inland field stations
SO BioScience 14(3):41-42
DE Biology
; Management
; Mountain Research Station - Location
AB None
$
CL 1417
AU Parker, E.R.
; Sanford, R.L.
DT 1999
TI The effect of mobile tree islands on soil phosphorus concentrations and distribution in an alpine ecosystem
SO Arctic, Antarctic, and Alpine Research. 31:16-20
DE None
AB Niwot Ridge is populated by moving patches of trees that form islands of woody vegetation in a habitat dominated by graminoids. This study determined the amounts and distribution of soil phosphorous (P) in relation to tree islands. As tree islands retreat to leeward, we hypothesize that the colonized soils would become both depleted in organic P (Po) and would possess more geochemically bound P than the adjacent tundra. A modified Hedley sequential fractionation indicated that the individual soil P fractions, along with the sums of thesse fractions, did not differ significantly between tundra, windward and leeward sites. Overall, soil P appears to be distributed in almost equal portions between geochemical and biological forms. The lack of significant change of soil P concetrations and distribution in response to tree island passage on Niwot Ridge is likely due to the lack of recent glaciation ad well as a long history of infrequent disturbances.     $
CL 1350
AU Parker, E.R.
; Sanford, R.L.
DT 1999
TI The effects of mobile tree islands on soil phosphorus concentrations and distribution 
 in an alpine tundra ecosystem on Niwot Ridge, Colorado Front Range, U.S.A
SO Arctic, Antarctic, and Alpine Research 31:16-20
DE NWTLTER
; alpine
; tree islands
; soil
; phosphorus
AB Niwot Ridge is populated by moving patches of trees that form islands
 of woody vegetation in a habitat dominated by graminoids. This study
 determined the amounts and distribution of soil phosphorus (P) in relation
 to tree islands. As tree islands retreat to leeward, we hypothesize that
 the colonized soils would become both depleted in organic P (Po) and
 would possess more geochemically bound P than in the adjacent tundra.
 A modified Hedley sequential fractionation indicated that the individual
 soil P fractions, along with the sums of these fractions, did not differ
 significantly between tundra, windward, and leeward sites. Overall, soil
 P appears to be distributed in almost equal portions between geochemical
 and biological forms. The lack of significant change of soil P is
 likely due to the lack of recent glaciation as well as a long history
 of infrequent perturbances.
$
CL 0723aa
AU Parrish, D.D.
; Fahey, D.W.
; Williams, E.J.
; Liu, S.C.
; Trainer, M.
; Murphy, P.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
DT 1986
TI Background ozone and anthropogenic ozone enhancement at Niwot Ridge,
 Colorado
SO Journal of Atmospheric Chemistry, 4:63-80
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; anthropogenic
; atmospheric chemistry
; ozone
AB None
$
CL 0724aa
AU Parrish, D.D.
; Trainer, M.
; Williams, E.J.
; Fahey, D.W.
; Hubler, G.
; Eubanks, C.S.
; Liu, S.C.
; Murphy, P.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
DT 1986
TI Measurements of the NOx-O3 photostationary state at Niwot Ridge, Colorado
SO Journal of Geophysical Research, 91:5361-5370
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; nitrogen compounds
AB None
$
CL 0723a
AU Parrish, D.D.
; Norton, R.B.
; Bollinger, M.J.
; Liu, S.C.
; Murphy, P.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
; Huebert, B.
DT 1986
TI Measurement of HNO3 and NO3 particulates at a rural site in the Colorado
 mountains
SO Journal of Geophysical Research, 91:5379-5393
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; nitrogen compounds
AB None
$
CL 1309
AU Pauker, S.J.
; Seastedt, T.R.
DT 1996
TI Effects of mobile tree islands on soil carbon storage in tundra ecosystems
SO Ecology 77(8): 2563-2567
DE NWTLTER
; tree islands
; krummholz
; carbon
AB None
$
CL 1207
AU Payton, E.A.
DT 1985
TI Rainfall and snowmelt frequency in the Boulder Watershed, Colorado
SO M.S. thesis, University of Colorado, Boulder
DE NWTLTER
; City of Boulder Watershed
; Green Lakes Valley
; hydrology
; precipitation
; meteorology
; snowmelt
AB None
$
CL 0724a
AU Payton, E.A.
; Brendecke, C.M.
; Sweeten, J.G.
; Michaels, P.S.
; James, E.D.
; Sarantitis, B.
DT 1985
TI Hydrological studies in an alpine watershed, Colorado Front Range (a
 collection of papers reprinted from the Proceedings of the 53rd Annual Western
 Snow Conference)
SO University of Colorado Long-Term Ecological Research Data Report 85/8. 38 pp
DE Data Report
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Watershed
AB None
$
CL 0724b
AU Payton, E.A.
; Brendecke, C.M.
DT 1985
TI Rainfall and snowmelt frequency in an alpine watershed
SO In:  Proceedings of the 53rd Annual Western Snow Conference pp. 25-36
DE Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Watershed
; NWTLTER
AB None
$
CL 1265
AU Peddle, D.R.
; Duguay, C.R.
; Deschamps, G.
DT 1993
TI Use of ancillary climate data in satellite image analysis of an 
 alpine tundra ecosystem, Front Range, Colorado Rocky Mountains
SO Pp 215-220 In: Proceedings of the 16th Canadian Symposium on Remote 
 Sensing and 8e Congres de l'Association quebecoise de teledetection, 
 Sherbrooke, Quebec, 7-10 June 1993
DE NWTLTER
; vegetation classification
; Landsat TM
; climatic indices
; digital elevation model
; precipitation
; temperature
; wind
; soil moisture
; snow distribution
AB The accuracy and precision of alpine vegetation classification at
 the Niwot Ridge LTER site were increased using climatic indices of
 precipitation, temperature, wind, soil moisture, and snow distribution
 derived from a 16-year archive of digital Landsat imagery, 
 geomorphometry from a DEM, and meteorological station data. Five 
 climatic indices were implemented: (i) orogenic precipitation index;
 (ii) slope-aspect index; (iii) snow probability index; (iv) insolation
 index; and (v) growing degree days. The highest maximum likelihood
 classification accuracies were obtained using all climate indices with
 two Landsat TM bands and ranged from 74% to 83% at the highest and
 lowest levels of precision tested with respect to the hierarchical
 Braun-Blanquet vegetati
2000
on classification system. These results were
 favourable for the sensor resolutions and classification algorithms
 used in this complex environment, and provide additional promise for
 future studies involving higher quality remote sensing and topographic
 data sets together with more sophisticated classification algorithms.
$
CL 0738
AU Pennak, R.W.
DT 1963
TI Ecological and radiocarbon correlations in some Colorado mountain lake and
 bog deposits
SO Ecology, 44:1-15
DE Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Invertebrates
; Lake
; Dating - Radiocarbon and Other
; Plankton
AB None
$
CL 0735
AU Pennak, R.W.
DT 1945
TI Hydrography and morphometry of some northern Colorado Lakes
SO University of Colorado Studies, Series D-2: 245-262
DE Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Lake
; Stream
; Plankton
; Invertebrates
AB None
$
CL1467
AU Pepin, N.
; Losleben, M.V.
DT 2002
TI Climate change in the Colorado Rocky Mountains: Free air versus temperature trends
SO International Journal of Climatology, v.22, pp 311-329
DE NWTLTER
AB None
$
CL1549
AU Pepin, N.C.
DT 2000
TI Twentieth-century change in the climate record for the Front Range, CO, USA.
SO Artc. Antarct. Alp. Res. vol. 32 pp. 135-146.
DE NWTDATA
; NIWOT RIDGE
; TEMPERATURE
; MODEL
AB The long-term climate records of the Mountain Research Station (MRS) at the University of Colorado cover a range of elevations from the lower montane forest zone (similar to 2000-2400 m), through the upper montane forest (similar to 2400-2800 m) and subalpine forest (similar to 2800-3300 m) to the alpine tundra (>3300 m) on Niwot Ridge, Colorado. Temperature records from all four MRS sites and the additional high plains site of Longmont (1509 m) are analyzed for the period 1952-1997, after extraction of much extra data from the original thermograph charts. The records are adjusted for instrumental changes where necessary and all four records are judged to be homogenous. Contrasting temporal trends are uncovered at the various elevations with warming at middle elevations and absolute cooling above the treeline in the alpine tundra. The resulting increased surface-based lapse rates do not arise from changes in relative frequencies of airflow types as is shown by a synoptic analysis based on objective airflow indices. Lapse rate increases are most systematic for synoptic classes with westerly components and during fall, winter, and spring. Climate at high elevations of the Front Range appears to be responding in an unusual way to global-warming influences.
$
CL 0740
AU Petersen, B.
DT 1968
TI Pollination of some tundra plants with miniature flowers on Niwot Ridge in
 Boulder County, Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 106 pp.
DE Dissertation
; Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Invertebrates
; Pollination
AB None
$
CL 0742
AU Petersen, B.
DT 1977
TI Pollination of Thlaspi alpestre by selfing and by insects in the alpine zone
 of Colorado
SO Arctic and Alpine Research, 9:211-215
DE Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Invertebrates
; Pollination
AB None
$
CL 0741
AU Peterson, B.
DT 1977
TI Pollination by ants in the alpine tundra of Colorado
SO Transactions Illinois State Academy of Science, 70(3/4):349-355
DE Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Invertebrates
; Pollination
AB None
$
CL 0742a
AU Peterson, B. V.
DT 1989
TI An unusual black fly (Diptera: Simuliidae) representing a new genus and new
 species
SO Journal of the New York Entomological Society 97:317-331
DE article
; taxonomy
; Long-Term Ecological Research Program
; Boulder City Watershed
; Insects
; distribution
; NWTLTER
AB None
$
CL 0742b
AU Petzold, E.
; Ruwisch, K.
; Holtmeier, F.K.
DT 1984
TI Multiregressive Abschatzung von Windsystemkomponenten am Beispiel der
 Colorado Front Range, USA
SO Verhandlungen der Gesellschaft fur Okologie, Bern, 1982. Bd.12, 219-225
DE article
; ecology
; climatology
; Mountain Research Station
; Indian Peaks Region
; wind
AB None
$
CL 0743
AU Pewe, T.L.
DT 1983
TI Alpine permafrost in the contiguous United States: A review
SO Arctic and Alpine Research, 15:145-156
DE Geomorphology
; Niwot Ridge
; Permafrost
; Overview
AB None
$
CL 0744
AU Phillips, M.P.
; Goldan, P.D.
; Sievers, R.E.
; Fehsenfeld, F.C.
DT 1979
TI Enhancement of electron capture detector sensitivity to non-electron
 attaching compounds using N20 carrier gas doping
SO American Society for Mass Spectrometry Meeting, Seattle. Abstract
DE Abstract
; Technique
; Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0745
AU Phillips, V.D., III
DT 1982
TI Responses by alpine plants and soils to microtopography within sorted
 polygons
SO Ph.D. dissertation, University of Colorado, Boulder. 208 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Soil
; Periglacial
; Demography
; Distribution
AB None
$
CL1545
AU Pielke, R.A.
; Stohlgren, T.
; Schell, L. 
; Parton, W.
; Doesken, N.
; Redmond, K. 
; Moeny, J. 
; McKee, T. 
; Kittel, T.G.F. 
DT 2002
TI Problems in evaluating regional and local trends in temperature: An example from eastern Colorado, USA
SO INTERNATIONAL JOURNAL OF CLIMATOLOGY vol. 22 no. 4 pp. 421-434
DE NWTDATA
; temperature trends
; weather trends
; geographic anomalies
; global change
; regional climate
AB We evaluated long-term trend,, in average maximum and minimum temperatures. threshold temperatures, and growing season in eastern Colorado. USA. to explore the potential shortcomings of many climate-change studies that either: ( 1) generalize regional patterns from single station,,. single seasons. or a few parameters over short duration from averaging dissimilar stations: or (2) generalize an a average regional pattern from coarse-scale general circulation models. Based on I I weather stations, some trends Acre weakly regionally consistent with previous studies of night-time temperature warming. Long-term (80 + year,,) mean minimum temperatures increased significantly ( P < 0.2) in about half the stations in winter. spring. and autumn and six Stations had significant decreases in the number of days per year with temperatures less than or equal to - 17.8 C (less than or equal to0 F), However, spatial and temporal variation in the direction of change as enormous for all the other weather parameters tested. and, in the majority of tests, few stations showed significant trend, (even at P < 0.2). n summer. four stations had significant increases and three stations had significant decreases in minimum temperature,,,. producing a strongly mixed regional signal, Trend,, in maximum temperature varied seasonally and geographically, as did trends in threshold temperature days greater than or equal to32.2 C (greater than or equal to90 F) or days greater than or equal to37.8 C (greater than or equal to100 F). There was evidence of a subregional cooling in autumn's maximum temperature,,, with five stations showing significant decreasing trends. There were many geographic anomalies where neighbouring weather stations differed greatly in the magnitude of change or where they had significant and opposite trends. We conclude that sub-regional spatial and seasonal variation cannot be ignored when evaluating the direction and magnitude of climate change, It is unlikely that one or a few weather stations are representative of regional climate trends. and equally unlikely that regionally projected climate change from coarse-scale general circulation models will accurately portray trends at sub-regional scales. However. the assessment of a group of stations for consistent more qualitative trend, (Such as the number of days less than -17.8 degreesC, such as we found) provides a reasonably robust procedure to evaluate climate trends and variability. Copyright (C) 2002 Royal Meteorological Soci
2000
ety.
$
CL1547
AU Pielke, R.A. 
; Stohlgren, T. 
; Parton, W.
; Doesken, N. 
; Moeny, J. 
; Schell, L. 
; Redmond, K.
DT 2000
TI Spatial representativeness of temperature measurements from a single site
SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY vol. 81 no. 4 pp. 826-830
DE NWTDATA
AB This paper discusses the spatial distribution of the early spring minimum temperature and the length of the growing season in eastern Colorado. It is shown that even in the relatively homogeneous landscape, there are significant differences in long-term trends of these data. The authors conclude that the direction and magnitude of regional climate trends cannot be reliably inferred from single-site records, even over relatively homogeneous terrain.
$
CL 0746a
AU Pollak, O.
; Phillips, S.
; Herger, L.
; Shaw, K.
DT 1988
TI Procedures manual for plant community dynamics subproject
SO University of Colorado Long-Term Ecological Research Data Report 88/1. 61 pp
DE Data Report
; Technique
; Ecology
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Plants
; Phenology
; Productivity
; Reproduction
; Community
; Growth (Development)
; Population
AB None
$
CL 0747
AU Pollock, R.
DT 1970
TI What colors the mountain snow?
SO Sierra Club Bulletin, 55(4): 18-20
DE Ecology
; Niwot Ridge
; Algae
; Snow
AB None
$
CL 1510
AU Pomeroy, J.W.
; Holler, P.
; Marsh, P.
; Walker, D.A.
; Williams M.W. 
DT 2001
TI Snow vegetation interactions: issues for a new initiative
SO in, (eds. A.J. Dolman, A.J. Hall, M.L. Kavvas, T. Oki and J.W. Pomeroy) Soil-Vegetation-Atmosphere Transfer Schemes and Large Scale Hydrological Models.  IAHS Publ. No. 270, IAHS Press, Wallingford, UK 299-305
DE NWTLTER
AB None
$
CL 0749
AU Pratte, J.F.
; Clark, R.J.
DT 1983
TI PROFS MESONET - description and performance
SO Preprint volume: Fifth Symposium on Meteorological Observations and
 Instrumentation, Toronto, Ontario, Canada, April 11-15, 1983. Boston,
 Massachusetts: American Meteorological Society, 303-307
DE Technique
; Climatology
; NOAA - Profs
; C-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0752
AU Quick, H.F.
DT 1966
TI Population of small mammals in the Boulder City watershed and a preliminary
 estimate of biomass cycle in 1964
SO Attachment No. 11 to USAEC Contract No. AT(11-1)-1191. Radio-ecology of the
 Colorado Front Range, Osburn, W.S., Principal Investigator, mimeographed
DE Technical report
; Ecology
; Atomic Energy Commission
; Boulder Watershed and Rainbow Lakes
; Mammals
; Biomass
AB None
$
CL 0753
AU Quinn, B. G.
DT 1962
TI Seasonal plankton studies on a Colorado mountain flowage
SO Ph.D. dissertation, University of Colorado, Boulder. 89 pp.
DE Dissertation
; Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Stream
; Phenological (seasonal)
; Plankton
AB None
$
CL 1369
AU Raab, T.K.
; Lipson, D.A.
; Monson, R.K.
DT 1999
TI Soil amino acid utilization among species of the Cyperaceae:
 plant and soil processes
SO Ecology 80:2408-2419
DE NWTLTER
; alpine
; amino acids
; ammonium uptake
; Carex
; Cyperaceae
; Cyperus
; Kobresia
; nitrate uptake
; nutrient uptake
; proteolysis
; shortgrass steppe
; subalpine fen
AB Amino acids are released during the decomposition of soil organic matter and 
 have been shown to be utilized as a nitrogen source by some non-mycorrhizal 
 species in the family Cyperaceae (the sedge family).  Twelve out of 13 Cyperaceae 
 species examined in the current study were capable of absorbing soil amino acids 
 in the non-mycorrhizal state.  With two exceptions (two species in the genus Kobresia), 
 species from subalpineor alpine habitats exhibited lower rates of total nitrogen 
 uptake compared to species from more temperate habitats, which is possibly explained 
 by lower growth rates in the alpine and subalpine species and a lower overall demand 
 for soil nitrogen.  The alpine and subalpine species exhibited higher rates of glycine 
 uptake relative to NH4+ and NO3- uptake, compared to species from the more temperate 
 habitats.  This may reflect specialization toward the uptake of organic N in the alpine 
 and subalpine species. 
 In three ecosystems where sedges commonly occur, amino acids were present in the 
 soil pore water, but in highly variable amounts.  Seasonal maximum amino acid 
 concentrations in alpine soil pore water ranged from 13 to 158 micromol/L in 
 four dry meadow sites.  The most common amino acid i these alpine soils was glycine.  
 In a subalpine fen habitat, aspartate was the most commonly observed amino acid, and 
 total amino acid concentrations were 15-20 micromol/L.  In a shortgrasssteppe habitat, 
 glutamate was the most abundant amino acid, and total amino acid concentrations were 
 25-45 micromol/L. 
 Soil protease activities correlated positively with soil protein content when all 
 three ecosystems (alpine, subalpine fen, and shortgrass steppe) were considered together.  
 The addition of protein (as casein) significantly increased soil protease activity, 
 indicating that soil protein content contributes to the capacity to generate soil amino 
 acids.  Soil protein contents correlated positively with total soil N content when the 
 alpine and shortgrass steppe sites were considered together.  The retention of NH4+ and 
 amino acids on the alpine soil was high compared to soils of lower organic matter content 
 that have been investigated in past studies.  We conclude that (1) the potential to take up 
 amino acids in non-mycorrhizal roots of the family Cyperaceae is widespread among species 
 native to a variety of different habitats, (2) amino acids are available for uptake 
 (though most abundant in the alpine), (3) the potential to generate soil amino acids 
 is proportional to soil protein concentration, and (4) soil amino acids can be 
 retained in the soil at high levels, leading to the conclusion that the soil binding 
 affinity of amino acids may constrain uptake by plant roots and miroorganisms.  
$
CL 1312
AU Raab, T.K.
; Lipson, D.A.
; Monson, R.K.
DT 1996
TI Non-mycorrhizal uptake of amino acids by roots of the alpine sedge
 Kobresia myosuroides: implications for the alpine nitrogen cycle
SO Oecologia 108:488-494
DE NWTLTER
; alpine plants
; nitrogen cycle
; cyperaceae
; tundra
; organic nitrogen
AB Non-mycorrhizal plants of the alpine sedge, Kobresia myosuroides, take
 up the amino acid glycine from nutrient solutions at greater rates than
 NO3- or NH4+. The amino acids glutamate and proline were also taken up 
 at high rates. Total plant biomass was twice as high after 4 months of
 growth on glycine, compared to NH4NO3, with significant increases in both
 root and leaf biomass. By taking advantage of differences in the delta 13C
 signature of air in the growth chamber and the glycine used for growth, a
 two-member mixing model was used to estimate that a significant amount of
 the glycine was taken up as intact molecules, enough to contribute 16% of
 the total carbon assimilation over a 4-month growing period. Glycine uptake
 was inhibited when roots were exposed to N2 in place of air, and when the
 protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) was added to
 the root solution. From these results it is concluded that glycine uptake
 occurs through active transport. Glycine uptake exhibited a Q10 of 2.0 
 over the temperature range 5-15 degrees C, with relatively high rates 
 maintained at the lowest temperature measured (5 degrees C). Roots of
 Kobresia were not capable of taking up NH4+ at measurable rates. To our 
 knowledge, this is the first report of a plant whose non-mycorrhizal roots
 cannon take up NH4+. Measurements of three N fractions (NO3-, NH4+, and
 total amino acids) in the soil pore water were made over two growning
 seasons in two Kobresia dry meadows using microlysimeters. At the West
 Knoll site, which is characterized by soils with average amounts of organic
 matter, the dominant forms of N in the soil pore water w
2000
ere NO3- and NH4+
 (0-450 micromoles per liter). Amino acid concentrations were generally
 less than 20 micromoles per liter at this site. At the East Knoll site,
 which is characterized by soils with higher than average amounts of organic
 matter, amino acids were generally present at higher concentrations 
 (17-100 micromoles per liter), compared to NO3- and NH4+. The most abundant
 amino acids were glycine (10-100 micromoles per liter), glutamate (5-70
 micromoles per liter), and late in the season cysteine (5-15 micromoles
 per liter). The results demonstrate that this sedge, which dominates
 dry meadow communities in many alpine ecosystems, is capable of taking
 up intact amino acids as a principal N source, and has access to high
 amino acid concentrations in certain alpine soils. Such uptake of organic
 N may accommodate plant N demands in the face of snow alpine N mineralization
 rates due to cold soil temperature.
$
CL 1399 
AU Rattray, G.
; Sievering, H.
DT 2001
TI Dry deposition of ammonia, nitric acid, and nitrate to alpine tundra at     Niwot Ridge, CO
SO Atmospheric Environment 35:1085-1109.
DE None
AB None
$
CL 0774
AU Raven, K.A.
DT 1948
TI Ecology of a timberline area in the Colorado Front Range
SO M.S. thesis, University of Colorado, Boulder.  83 pp.
DE Thesis
; Ecology
; University of Colorado
; Niwot Ridge
; Forest-Tundra Ecotone (Timberline)
; Spermopsida
AB None
$
CL 0779
AU Reddy, M.M.
; Liebermann, T.D.
; Jellinski, J.C.
; Caine, N.
DT 1985
TI Variation in pH during summer storms near the Continental Divide in Central
 Colorado, U.S.A.
SO Arctic and Alpine Research, 17:79-88
DE Climatology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; C-1 Climate Station
; Acid Deposition
; Precipitation
; Chemistry
; NWTLTER
AB None
$
CL 0778b
AU Reddy, M.M.
; Caine, N.
DT 1990
TI A small alpine basin budget: Front Range, Colorado
SO In: International Mountain Watershed Symposium: Subalpine processes and
 water quality. I. G. Poppoff, C. R. Goldman, S. L. Loeb and L. B. Leopold
 editors. Tahoe Resource Conservation District, South Lake Tahoe, CA. pp.
 370-385
DE article
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; water
; watershed
; precipitation
; snow
; stream
; lake
; glacier
; NWTLTER
AB None
$
CL 0778a
AU Reddy, M.M.
DT 1988
TI Chemical budget for a small alpine basin in Colorado
SO Eos, 69(44):1214. Abstract
DE Abstract
; Soil Sciences
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Acid Deposition
; Chemistry
; Precipitation
AB None
$
CL 0782
AU Reheis, M.J.
DT 1974
TI Source, transportation, and deposition of debris on Arapaho Glacier, Front
 Range, Colorado
SO M.S. thesis, University of Colorado, Boulder. 71 pp.
DE Thesis
; Geomorphology
; Glaciology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Altitude
; Soil
; Wind
; Periglacial
; Glacier
AB None
$
CL 0784
AU Reheis, M.J.
DT 1975
TI Source, transportation and deposition of debris on Arapaho Glacier, Front
 Range, Colorado, U.S.A
SO Journal of Glaciology, 4(72):407-420. Reprinted in: Ives, J.D. (ed.), 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 174-186
DE Geomorphology
; Glaciology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Altitude
; Soil
; Wind
; Periglacial
; Glacier
AB None
$
CL 0783
AU Reheis, M.J.
DT 1974
TI Source, transportation, and deposition of debris on Arapahoe Glacier, Front
 Range, Colorado
SO Geological Society America, Abstracts with Programs, 6(7):469-470. Abstract
DE Abstract
; Geomorphology
; Glaciology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Altitude
; Soil
; Wind
; Periglacial
; Glacier
AB None
$
CL 1334
AU Reich P.B.
; Walters M.B.
; Ellsworth D.S.
; Vose J.M.
; Volin J.C.
; Gresham C.
; Bowman W.D.
DT 1998
TI Relationships of leaf dark respiration to leaf nitrogen, specific
 leaf area and leaf life-span: a test across biomes and functional groups
SO Oecologia 114:471-482
DE NWTLTER
; respiration
; leaf life-span
; specific leaf area
; nitrogen
; functional groups
AB Based on prior evidence of coordinated multiple leaf trait scaling,
 we hypothesized that variation among species in leaf dark respiration
 rate (Rd) should scale with variation in traits such as leaf nitrogen
 (N), leaf life-span, specific leaf area (SLA), and net photosynthetic
 capacity (Amax). However, it is not known whether such scaling, if it
 exists, is similar among disparate biomes and plant functional types. We
 tested this idea by examining the interspecific relationships between
 Rd measured at a standard temperature and leaf life-span, N, SLA and
 Amax for 69 species from four functional groups (forbs, broad-leafed
 trees and shrubs, and needle-leafed conifers) in six biomes traversing
 the Americas: alpine tundra/subalpine forest, Colorado; cold temperate
 forest/grassland, Wisconsin; cool temperate forest, North Carolina;
 desert/shrubland, New Mexico; subtropical forest, South Carolina; and
 tropical rain forest, Amazonas, Venezuela. Area-based Rd was positively
 related to area-based leaf N within functional groups and for all species
 pooled, but not when comparing among species within any site. At all sites,
 mass-based Rd (Rd-mass) decreased sharply with increasing leaf life-span
 and was positively related to SLA and mass-based Amax and leaf N (leaf
 Nmass). These intra-biome relationships were similar in shape and slope
 among sites, where in each case we compared species belonging to different
 plant functional groups. Significant Rd-mass - Nmass relationships were
 observed in all functional groups (such as forbs) with higher SLA and
 shorter leaf life-span, Nmass and/or SLA (r^2 >= 0.79, P < 0.001). At
 any given SLA, Rd-mass rises with increasing Nmass and/or decreasing leaf
 life-span; and at any level of Nmass, Rd-mass rises with increasing SLA
 and/or decreasing leaf life-span. The relationships between Rd and leaf
 traits observed in this study support the idea of a global set of predictable
 interrelationships between key leaf morphological, chemical and metabolic 
 traits.
$
CL 1361
AU Reich, P.B.
; Ellsworth, D.S.
; Walters, M.B.
; Vose, J.M.
; Gresham, C.
; Volin, J.C.
; Bowman, W.C.
DT 1999
TI Generality of leaf traits: a test across six biomes
SO Ecology 80: 1955-1969
DE NWTLTER
AB Convergence in interspecific leaf trait relationships across diverse taxonomic 
 groups and biomes would have improtant evolutionary and ecological implications.  
 Such convergence has been hypothesised to result from trade-offs that limit the 
 combination of plant traits for any species.  Here we address this issue by testing 
 for biome differences in the slope and intercept of specific relationships among leaf 
 traits: longevity, net photosynthetic capacity (A max), leaf diffusive conductance (G s), 
 specific leaf area (SLA), and nitrogen (N) status, for more than 100 species in six 
 distinct biomes of the Americas.  The six biomes were: alpine tundra -subalpine forest 
 ecotone, cold temperate forest-prairie ecotone, montane cool temperate forest, desert 
 shrubland, subtropical forest, and tropical rain forest.  Despite large differences in 
 climate and evolutionary history, in all biomes mass-based leaf N (N mass), SLA, G s, 
 and A max were positively related to one onother and decreased with increasing leaf life 
 span.  The relationships between pairs of leaf traits exhibited similar slopes among biomes, 
 suggesting a predictable set of scaling relationships among terrestrial ecosystems 
 regardless of biome or vegetation type.  However, the intercept (i.e., the overall 
 elevation of regression lines) of relationships between pairs of leaf traits usually 
 differed among biomes.  With increasing aridity across sites, species had greater A 
 max for a given level of G s and lower SLA for any 
2000
given leaf life span.  Using 
 principal components analysis, most variation among species was explained by an axis 
 related to mass-based leaf traits (A max, N, and SLA) while a second axis reflected 
 climate, G s, and other area-based leaf traits. 
$
CL 0787
AU Retzer, J.L.
DT 1974
TI Alpine soils
SO In: Ives, J.D. and Barry, R.G. (eds.), Arctic and Alpine Environments.
 London: Methuen, 771-802
DE Soil sciences
; Niwot Ridge
; Soil
; Precipitation
; Climate - Discussion of
; Plant
AB None
$
CL 0786
AU Retzer, J.L.
DT 1956
TI Alpine soils of the Rocky Mountains
SO Journal of Soil Science, 7:22-32
DE Soil sciences
; Soil
; Overview
AB None
$
CL 0788
AU Reynolds, D.W.
DT 1983
TI Prototype workstation for mesoscale forecasting
SO Bulletin of the American Meteorological Society, 64(3):264-273
DE Technique
; Climatology
; NOAA - Profs
; C-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0789
AU Reynolds, G.F.
DT 1978
TI Record of decision for USDA, Forest Service
SO Environmental Assessment Report, Como Creek Greenback Cutthroat Trout
 Restoration Project - Roosevelt National Forest, Boulder, County, Colorado.
 USDA Forest Service, Rocky Mountain Region, Fort Collins, Colorado
DE Management
; Mountain Research Station - Location
; Stream
; Fish
AB None
$
CL 1325
AU Rikkers, M.
DT 1997
TI Spatial variability of liquid water in a continental alpine snowpack:
 Niwot Ridge Colorado.
SO M.S. thesis, University of Colorado, Boulder. 74 pp.
DE NWTLTER
; melwater
; snowfileds
AB None
$
CL 0793
AU Rink, L.P.
DT 1984
TI Temporal and spatial distribution of Acomastylis rossii over an alpine
 tundra site
SO New Mexico Journal of Science, 24(1):47-48
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Snow
; Distribution
; Phenological (seasonal)
AB None
$
CL 0794
AU Rissing, J.M.
; Thorn, C.E.
DT 1985
TI Particle size and clay mineral distribution within sorted and nonsorted
 circles and the surrounding parent material, Niwot Ridge, Front Range,
 Colorado, U.S.A.
SO Arctic and Alpine Research, 17:153-163
DE Geomorphology
; Sedimentology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Soil
; Periglacial
AB None
$
CL 0795
AU Robbins, W.W.
DT 1910
TI Climatology and vegetation in Colorado
SO Botanical Gazette, 49:256-280
DE Climatology
; Ecology
; History
; Spermopsida
; Climate - Discussion of
; Distribution
AB None
$
CL 0800a
AU Roberts, J.M.
; Langford, A.O.
; Goldan, P.D.
; Fehsenfeld, F.C.
DT 1988
TI Ammonia measurements at Niwot Ridge, Colorado, and Point Arena, California,
 using the tungsten oxide denuder tube technique
SO Journal of Atmospheric Chemistry 7:137-152
DE article
; NOAA - Aeronomy Lab
; Atmospheric Science
; C-1 Climate Station
; atmospheric chemistry
; nutrients
; nitrogen compounds
AB None
$
CL 0800b
AU Roberts, J.M.
; Norton, R.B.
; Goldan, P.D.
; Fehsenfeld, F.C.
DT 1987
TI Evaluation of the tungsten oxide denuder tube technique as a method for the
 measurement of low concentrations of nitric acid in the troposphere
SO Journal of Atmospheric Chemistry 5:217- 238
DE article
; NOAA - Aeronomy Lab
; Atmospheric Science
; C-1 Climate Station
; atmospheric chemistry
; nutrients
; nitrogen compounds
AB None
$
CL 0798
AU Roberts, J.M.
; Fehsenfeld, F.C.
; Albritton, D.L.
; Sievers, R.E.
DT 1984
TI Sampling and analysis of monoterpene hydrocarbons in the atmosphere with
 Tenax GC porous polymer
SO In: Keith, L.H. (ed.), Identification and Analysis of Organic Pollutants in
 Air. Woburn, Massachusetts: Butterworth Publishers, 371-387
DE Technique
; Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0797a
AU Roberts, J.M.
; Fehsenfeld, F.C.
; Albritton, D.L.
; Sievers, R.E.
DT 1983
TI Measurements of monoterpene hydrocarbons at Niwot Ridge, Colorado
SO Journal of Geophysical Research, 88(C15):10667-10678
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
AB None
$
CL 0799
AU Roberts, J.M.
; Goldan, P.D.
; Albritton, D.L.
; Fehsenfeld, F.C.
; Sievers, R.E.
DT 1982
TI Measurements of atmospheric hydrocarbons at a remote rural site
SO Proceedings 2nd Symposium on the Composition of the Nonurban Troposphere.
 Williamsburg, VA, May 25, 1982. American Meteorological Society. Boston,
 Massachusetts. 281-283
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0800
AU Roberts, J.M.
; Goldan, P.D.
; Albritton, D.L.
; Fehsenfeld, F.C.
DT 1982
TI Techniques for the measurements of atmospheric hydrocarbons at a remote
 rural site
SO Symposium on Pollutant Monitoring of Ambient Air and Stationary Sources,
 Raleigh, NC, May 4-7, 1982
DE Technique
; Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 1362
AU Robertson. G.P.
; Wedin, D.
; Groffman, P.M.
; Blair, J.M.
; Holland, E.A.
; Nadelhoffer, K.J.
; Harris, D.
DT 1999
TI Soil carbon and nitrogen availability: Nitrogen mineralization, nitrification and
 soil respiration potentials
SO In Robertson, G.P. et al. (eds.) Standard Soil Methods for Long-Term Ecological Research.
 Oxford Press. Pp. 258-271
DE NWTLTER
; soil
; carbon
; nitrogen
AB None
$
CL 0801
AU Rodeck, H.G.
DT 1941
TI Distribution problems in some moraine ponds
SO University of Colorado Studies, Series D, 1(3)
DE Flora
; Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Algae
; Angiosperms
; Bryophytes
; Molluscs
; Lake
; Distribution
; Periglacial
AB None
$
CL 1281
AU Rusch, D.
; Sievering, H.
DT 1995
TI Variation in ambient air nitrogen concentration and total annual
 atmospheric deposition at Niwot Ridge, Colorado
SO Pp. 23-32 In Tonnessen, K. A., M. W. Williams, and M. Tranter (eds.).
 Biogeochemistry of Seasonally Snow Covered Basins. International
 Association of Hydrological Sciences, Wallingford, UK, IAHS-AIHS
 Publication no. 228. 465 pp.
DE NWTLTER
; Niwot Ridge
; atmospheric deposition
; nitrogen
; particulate nitrate
; ammonium
; C-1
; nitric acid
; Saddle
; sulfate
; gaseous ammonia
; anthropogenic pollution
AB Sampling of ambient air concentrations of particulate nitrate (pNO3-) and 
 ammonium (pNH4+) has been ongoing at the subalpine site of the University 
 of Colorado's Mountain Research Station (MRS), known as C-1 (3018 m), for 
 the summer seasons of 1993 and 1994. Year-round sampling of pNO3-, pNH4+, 
 and nitric acid (HNO3) have also been undertaken at the tundra site of the
 MRS, the Saddle site (3520 m), since January 1993. Additionally, analysis 
 for particulate sulfate (SO42-) and trial sampling of gaseous ammonia (NH3) 
 was begun at C-1 the summer of 1994. The comparison of the data from the 
 C-1 and Saddle sites has shown variations in ambient concentrations of 
 these nitrogen species, leading to the conclusion that they are influenced 
 differently by wind and weather patterns. While the C-1 site is often 
 subject to upslope contamination by the Front Range metropolitan areas, 
 the Saddle remains a relatively pristine environment. A further comparison 
 of our data with those obtained at C-1 over a decade ago show an increase 
 of ambient concentrations and pollution inputs over time.
$
CL 0805
AU Ruwisch, K.
DT 1983
TI Windflow near soil surface/upper 4th of July Valley
SO Ph.D. dissertation, University of Munster, West Germany
DE Dissertation
; Climatology
; Ecology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Wind
; Morphological
; Tree
AB None
$
CL 0814
AU Rydberg, P.A.
DT 1915
TI Phytogeographical notes on the Rocky Mountain Region V: Grasslands of the
 subalpine and montane zones
SO Bulletin of the Torrey Botanical Club, 42:629-642
DE Ecology
; History
; Angiosperms
AB None
$
CL 0813
AU Rydberg, P.A.
DT 1915
TI Phytogeographical notes on the Rocky Mountain Region IV: Forests of the

2000

 subalpine and montane zones
SO Bulletin of the Torrey Botanical Club, 42:11-25
DE Ecology
; History
; Tree
; Conifers
; Angiosperms
AB None
$
CL 0815
AU Rydberg, P.A.
DT 1922
TI Flora of the Rocky Mountains and Adjacent Plains. 2nd edition
SO Published by the author, New York. 1143 pp.
DE Overview
; Ecology
; History
; Plant
AB None
$
CL 0810
AU Rydberg, P.A.
DT 1913
TI Phytogeographical notes on the Rocky Mountain Region I: alpine region
SO Bulletin of the Torrey Botanical Club, 40:677-686
DE Ecology
; History
; Tree
; Distribution
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0809
AU Rydberg, P.A.
DT 1906
TI Studies on the Rocky Mountain flora, XVI
SO Bulletin of the Torrey Botanical Club, 33:137-161
DE Taxonomy and systematics
; Distribution
; Plant
AB None
$
CL 0812
AU Rydberg, P.A.
DT 1914
TI Phytogeographical notes on the Rocky Mountain Region III: Formations the
 alpine zone
SO Bulletin of the Torrey Botanical Club, 41:459-474
DE Ecology
; History
; Distribution
; Angiosperms
AB None
$
CL 0816
AU Rydberg, P.A.
DT 1917
TI Phytogeographical notes on the Rocky Mountain region, VII: Formations in the
 subalpine zone
SO Bulletin of the Torrey Botanical Club, 44:431-454
DE Ecology
; History
; Plant
AB None
$
CL 0817
AU Saether, O.A.
DT 1970
TI Chironomids and other invertebrates from North Boulder Creek, Colorado
SO University of Colorado Studies, Series in Biology, 31:59-114
DE Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Stream
; Distribution
; Insects
; Invertebrates
AB None
$
CL 0724f
AU Sarantitis, B.
DT 1985
TI Temporal variations in snowmelt runoff from an alpine snowfield
SO In:  Proceedings of the 53rd Annual Western Snow Conference pp. 160-162
DE Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Water
; Chemistry
; Snow
; Stream
; Watershed
; NWTLTER
AB None
$
CL 0819a
AU Sarantitis, B.C.
DT 1986
TI Temporal variation in the runoff hydrograph of an alpine snowfield
SO M.A. thesis, University of Colorado, Boulder, 158 pp.
DE thesis
; hydrology
; Long-Term Ecological Research Program
; Boulder City Watershed
; snow
; water
; seasonal
; watershed
; NWTLTER
AB None
$
CL 1495
AU Schadt, C.W.
; Martin, A.P.
; Lipson, D.A.
; Schmidt, S.K.
DT 2003
TI Seasonal Dynamics of Previously Unknown Fungal Lineages in Tundra Soils
SO Science v. 301 pp. 1359-1361
DE NWTLTER
AB The finding that microbial communities are active under snow has changed the estimated global rates of biogeochemical processes beneath seasonal snowpacks.  We used microbiological and molecular techniques to elucidate the phylogenetic composition of undersnow microbial communities in Colorado, the United States.  Here we show that tundra soil microbial biomass reaches its annual peak under snow, and that fungi account for most of the biomass.  Phylogenetic analysis of tundra soil fungi revealed a high diversity of fungi and three novel clades that constitute major new groups of fungi (divergent at the subphylum or class level).  An abundance of previously unknown fungi that are active beneath the snow substantially broadens our understanding of both the diversity and biogeochemical functioning of fungi in cold environments.$
CL1453
AU Schadt, C.W.
; Mullen, R.B.
; Schmidt, S.K.
DT 2001
TI Isolation and phylogenetic identification of a dark-septate fungus associated with the alpine plant Ranunculus adoneus
SO New Phytologist v.150 pp 747-755
DE NWTLTER
AB None
$
CL 1557
AU Schmidt, S.K.
; Lipson, D.A.
DT 2004
TI Microbial growth under the snow: Implications for nutrient and allelochemical availability in temperate soils
SO Plant and Soil vol. 259 pp. 1-7
DE NWTLTER
; allelopathy
; litter decomposition
; nitrogen immobilization
; phenolic compounds
; snow-covered soils
; tundra
AB Recent work has shown that plant litter inputs fuel microbial growth in autumn and winter resulting in a large increase of microbial biomass under the snow pack in tundra soils. This winter-adapted microbial community can grow at low temperatures (-5 to 3 degrees C) and depletes the litter of easily degraded constituents, such as simple phenolic compounds, and immobilizes nitrogen. During snowmelt there is a die-off of this winter microbial community (due to starvation and intolerance to higher soil temperature) resulting in a release of nitrogen that can be utilized by plants and the summer microbial community. The summer microbial community can tolerate higher temperatures (5 to 20 degrees C) and utilizes mostly plant root exudates for growth. These yearly cycles of microbial growth dynamics have profound implications for both nutrient and alleochemical availability to plants. Firstly, these results show that release (from litter) and degradation of plant phenolic compounds (potential alleochemicals) occurs before plant growth commences in the spring. Secondly, nitrogen (N) immobilized by over-winter microbial growth is released back to the soil during and after snowmelt, thus becoming available to plants. Both of these results need to be incorporated in the design of experiments to explore plant-plant interactions. Many experiments in which chemicals (or fresh litter) are incorporated during plant growth do not reflect the fact that these two events are temporally uncoupled in many natural systems.
$
CL 1230
AU Schmidt, S.K.
DT 1992
TI Models for studying the population ecology of microorganisms in natural
 systems
SO Pp. 31-59 In: Hurst, C.J. (ed.). Modeling the Metabolic and Physiologic
 Activities of Microorganisms. New York: John Wiley and Sons
DE NWTLTER
; microbiology
; modeling
; population ecology
; microorganisms
; Monod equation
; population dynamics
AB None
$
CL 1437
AU Schmidt, S.K.
; West A.E.
; Brooks, P.D.
; Smith, L.K.
; Jaeger, C.H.
; Fisk, M.C.
; Holland, E.A.
DT 2001
TI Soil-atmosphere gas exchange
SO Chapter 13 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 1418    
AU Schmidt, S.K.
; Lipson, D.A.
; Raab, T.K.
DT 2000
TI Effects of willow (Salix brachycarpa) on populations of salicylate-mineralizing microorganismsin alpine soils
SO J. Chem. Ecol. 26: 2049-2057
DE None
AB None
$
CL1556
AU Schmidt, S.K.
; Lipson, D.A.
; Ley, R.E.
; Fisk, M.C.
; West, A.E.
DT 2004
TI Impacts of chronic nitrogen additions vary seasonally and by microbial functional group in tundra soils
SO Biogeochemistry vol. 69 pp. 1-17
DE NWTLTER
; Fertilization
; Microbial functional groups
; Microbial respiration
; Nitrogen cycling
; Nitrogen immobilization
; Tundra soils
AB Previous studies have shown that fertilization with nitrogen depresses overall microbial biomass and activity in soil. In the present study we broaden our understanding of this phenomenon by studying the seasonality of responses of specific microbial functional groups to chronic nitrogen additions in alpine tundra soils. We measured soil enzyme activities, mineralization kinetics for 8 substrates, biomass of 8 microbial functional groups, and changes in N and carbon pools in the soil. Our approach allowed us to compare the ability of the soil microbial biomass to utilize various substrates in addition to allowing us to estimate changes in biomass of microbial functional groups that are involved in carbon and nitrogen cycling. Overall microbial activity and biomass was reduced in fertilized plots, whereas pools of N in the soil and microbial biomass N were higher in fertilized plots. The negative effects of N were most prominent in the summer. Biomass of the dominant microbial functional groups recovered in fertilized soils during the winter and nitrogen storage in microbial biomass was higher in fertilized soils in the autumn and winter than in the summer. Microbial immobilization of N may therefore be a significant sink for added N during autumn and winter months when plants are not active. One large microbial group that did not recover in the winter in fertilized soils was phe
2000
nol mineralizers, possibly indicating selection against microbes with enzyme systems for the breakdown of phenolic compounds and complex soil organic matter. Overall, this work is a step towards understanding how chronic N additions affect the structure and biogeochemical functioning of soil microbial communities.$
CL 1355
AU Schmidt, S.K.
; Ley, R.L.
DT 1999
TI Microbial competition and bioavailability limit the expression of allelochemicals in 
 natural soils
SO In Inderjit, S., K.M.M. Dakshini and C.L. Foy (eds.). Principles and Practices in 
 Plant Ecology: Allelochemical Interactions. CRC Press.
DE NWTLTER
; soil
AB None
$
CL 1229
AU Schmidt, S.K.
DT 1992
TI A substrate-induced growth-response method for estimating the biomass of
 microbial functional groups in soil and aquatic systems
SO FEMS Microbiology Ecology 101: 197-206
DE NWTLTER
; microbial biomass
; functional groups
; substrate-induced respiration
; modeling
AB A substrate-induced growth-response (SIGR) method is presented for
 estimating the biomass or density of microorganisms capable of carrying out
 specific metabolic functions in natural and human-made systems. The biomass of
 active organisms can be estimated based on the concentration of substrate
 needed to induce growth of the standing population. Curves of substrate
 mineralization or depletion are used as indirect indicators of growth.
 Estimates of population size are obtained by using non- linear regression
 techniques to fit simple models, that contain biologically relevant
 parameters, to the substrate mineralizaton curves. In the present study, the
 SIGR method was used to estimate the numbers of organisms capable of
 mineralizing 2,4 dinitrophenol in soil and in a model waste-treatment system.
 The SIGR approach was tested by comparison of the model estimates for the same
 parameters obtained by independent means.
$
CL 0826
AU Schultz, C.B. (ed.)
; Smith, H.T.U., (ed.)
DT 1965
TI Guidebook for One-Day Field Conferences, Boulder Area, Colorado
SO International Association for Quaternary Research, VIIth Congress. 80 pp.
DE Niwot Ridge
; Mount Evans and Guanella Pass Region
; Rocky Mountain National Park - Location
; Guide
AB None
$
CL 1564
AU Scott-Denton, L.E.
; Sparks, K.L.
; Monson, R.K.
DT 2003
TI Spatial and temporal controls of soil respiration rate in a high-elevation, supalpine forest
SO Soil Biology and Biochemistry vol. 35 pp. 525-534
DE NWTLTER
AB We examined soil respiration to determine what measurable environmental variables can be used to predict variation in soil respiration rates, spatially and temporally, at a high-elevation, mixed conifer, subalpine forest site at the Niwot Ridge Ameriflux Site in Colorado. For three summers, soil respiration rates were measured using soil collars and a portable gas-exchange system. Transects of the collars were established to ensure spatial characterization of the litter-repleted areas beneath tree crowns and the litter-depleted open spaces between tree crowns. Soil temperature and soil moisture were both identified as important drivers of soil respiration rate, but were found to confound each other and to function as primary controls at different scales. Soil temperature represents a primary control seasonally, and soil moisture represents a primary control interannually. Spatially, organic layer thickness, ammonium concentration, water content, and the microbial and soil soluble carbon pools were found to predict variation from point to point. Soil microbial biomass strongly correlated to soil respiration rate, whereas root biomass was identified as a weak predictor of respiration rate and only when controlling for other variables. Spatial variation in soil respiration rate is highly determined by the depth of the soil organic horizon, which in this ecosystem varies predictably according to distance from trees. The conclusions that can be drawn from the study provide the foundation for the development of future models of soil respiration driven by fundamental variables of the climate and soil microenvironment.$ 
CL 1385
AU Seastedt, T.R.
DT 2000
TI Soil fauna and controls of carbon dynamics: Comparisons of rangelands and forests across latitudinal gradients
SO Pages 293-312 In: D.C. Coleman and P. Hendrix (eds.). Invertebrates as Webmasters in Ecosystems. CABI Publ., Wallington, UK.
DE None
AB None
$
CL 1388
AU Seastedt, T.R.
; Adams, G.A.
DT 2001
TI Effects of moblie tree islands on alpine tundra soils 
SO Ecology 82:8-15
DE NWTLTER
AB None
$
CL 1381
AU Seastedt, T.R.
DT 2000
TI Soil Fauna and controls of carbon dynamics: Comparisons of rangelands and forests 
 across latitudinal gradient
SO In D.C. Coleman and P.Hendrix (eds). Soil Arthropods as webmasters of Ecosystems.  
DE NWTLTER
; soil fauna
; carbon
AB None
$
CL 1424
AU Seastedt, T.R.
; Vaccaro, L.
DT 2001
TI Plant Species Richness, Productivity, and Nitrogen and Phosphorus Limitations across a Snowpack Gradient in Alpine Tundra, Colorado, U.S.A 
SO Arctic, Antarctic, and Alpine Research. 33(1): 100-106
DE Colorado
; Niwot Ridge
AB The extent to wich nutrient limitations affects species composition, abundance, and productivity of the alpine tundra is an ongoing area of ecological inquiry. At Niwot Ridge in the Front Range of Colorado, plant species richness and foliage production were studied with respect to N and P additions in three alpine communities varying in snowpack depth and duration. These effects were also measured in conjuction with a snowpack enhancement experiment.  Measurements of plant responses were made 4 yr following the initiation of hte manipulations. The addition of either N or P enhanced plant foliage productivity (P=0.05 and P=0.03 respectively). Nitrogen additions had a negative effect on species richness (P>0.001), while P additions had no effect on species richness (P>0/60). Snowpack did not affect foliage productivity (P=0.20), but species richness was negativelyiaffected (P<0.001). Snowpack also appeared to mediate species-specific responses to N and P additions. In the alpine, the relationship between species diversity and plant productivity is mediated by species-specific traits. After 4 yr, the increased peoduction by plant species sensitive to P additions did not reduce species richness. This suggests that production-induced competitive excution is not a generarlization that can be used to explain the decline in species richness. Moreover, the reduction in species richness due to N additiion occured across all the tundra communities studied here. These communities differ with respect to strength of other potential limiting resources such as light (self-shading) or water. Thus, this negative response is best explained by changes in the soil chemistry that resulted directly or indirectly from N additions.$
CL 1436
AU Seastedt, T.R.
; Walker, M.D.
; Bryant, D.M.
DT 2001
TI Controls on decomposition processes in alpine tundra
SO Chapter 11 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL1550
AU Seastedt, T.R.
; Bowman, W.D.
; Caine, T.N.
; McKnight, D.
; Townsend, A.
; Williams, M.W.
DT 2004
TI The Landscape Continuum: A Model for High Elevation Ecosystems
SO Bioscience vol. 54 no. 2 pp. 111-121
DE NWTLTER
; alpine
; aquaticterrestrial interactions
; climate
; nutrient deposition
; transport processes
AB Interactions between climate and ecosystems with complex topographic gradients generate unique source and sink habitats for water and nutrients as a result of precipitation, energy, and chemical redistribution.  We examined these phenomena for a high-elevation site in the Colorado Front Range.  Current changes in climate and atmospheric deposition of nitrogen to these systems are causing rapid changes in some portions of this system but not in others.  Using a conceptial model that links terrestrial ecosystems to each other and to aquatic ecosystems, we report how atmospheric inputs and endogenous resources can be amplified or attenuated by transport processes. 
2000
 High-elevation lakes and the alpine tundra-forest ecotone are expected to receive the brunt of anthropogenic inputs obtained from (a) the redistribution of exogenous materials from the regional environment and (b) endogenous sources originated in other montane areas.$
CL1479
AU Seastedt, T.R.
DT 2002
TI Base camps of the Rockies: The Intermountain Grasslands
SO In: Baron, J.S., D. Fagre, and R. Hauer (eds.) Rocky Mountain Futures: an Ecological Perspective. Island Press
DE None
AB None
$
CL 1429
AU Seastedt, T.R. 
DT 2001
TI Soils
SO Chapter 8. in: Bowman, W.D. and T.R. Seastedt (eds.) Structure and function of an alpine ecosystem: Niwot Ridge, Colorado. Oxford Press
DE None
AB None
$
CL 0830a
AU Shankman, D.
; Daly, C.
DT 1988
TI Forest regeneration above tree limit depressed by fire in the Colorado Front
 Range
SO Bulletin of the Torrey Botanical Club 115:272-279
DE article
; ecology
; University of Colorado
; Niwot Ridge
; Conifers
; revegetation
; fire
; forest-tundra ecotone
; growth
AB None
$
CL 0830
AU Shankman, D.
DT 1984
TI Tree regeneration following fire as evidence of timberline stability in the
 Colorado Front Range, U.S.A.
SO Arctic and Alpine Research, 16:413-417
DE Ecology
; University of Colorado
; Niwot Ridge
; Angiosperms
; Fire
; Tree
; Forest-Tundra Ecotone (Timberline)
; Revegetation
; NWTLTER
AB None
$
CL 0830c
AU Shea, K.L.
DT 1987
TI Effects of population structure and cone production on outcrossing rates in
 Engelmann spruce and subalpine fir
SO Evolution, 41:124-136
DE article
; ecology
; genetics
; University of Colorado
; Mountain Research Station
; conifers
; demography
; population
; seed
AB None
$
CL 0831
AU Shea, K.L.
DT 1985
TI Mating systems and population structure in Engelmann spruce and subalpine
 fir
SO Ph.D. dissertation, University of Colorado, Boulder.  170 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Distribution
; Reproduction
; Conifers
; Genetics
AB None
$
CL 0830b
AU Shea, K.L.
; Grant, M.C.
DT 1985
TI Clonal growth in spire-shaped Engelmann spruce and subalpine fir trees
SO Canadian Journal of Botany, 64:255-261
DE article
; ecology
; University of Colorado
; Mountain Research Station
; conifers
; growth
AB None
$
CL 0830aa
AU Shea, K.L.
DT 1985
TI Demographic aspects of coexistence in Engelmann spruce and subalpine fir
SO American Journal of Botany, 72:1823-1833
DE article
; ecology
; University of Colorado
; Mountain Research Station
; conifers
; demography
AB None
$
CL 1407
AU Sheriff, R.L.
DT 2000
TI Fire history at high elevation in the Colorado Front Range
SO M.A. Thesis, Geography, University of Colorado, Boulder. 85 pp.
DE None
AB None
$
CL 1522
AU Sherriff, R.L.
; Veblen, T.T.
; Sibold, J.S. 
DT 2001
TI Fire history in high elevation subalpine forests in the Colorado Front Range
SO Ecoscience v. 8 no. 3 pp. 369-380
DE NWTLTER
; fire
; climate change
; subalpine forests
; Colorado Front Range
; El Nino-Southern Oscillation
AB Resource managers rely on knowledge of fire history to guide management decisions, but for the subalpine zone of the Colorado Front Range little information exists on fire history documenting changes in fire regimes over the past several centuries. We examined fire history at 13 high elevation sites in the Colorado Front Range to detect long-term trends that may be related to changes in land use and/or to climatic variability. There is a high degree of spatial and temporal variation in fire regimes across sites; however, most sites exhibit an increase in fire frequency during the 20(th) century compared to the 19(th) century. We did not find any evidence that fire suppression after the creation of National Forests and Rocky Mountain National Park in the early 1900s decreased fire frequency at the highest elevations of forest cover in the Front Range. Human influences over the last 200 years have played less of a role in these high elevation subalpine forests than in the lower elevation forests of the Colorado Front Range. In the absence of effective fire exclusion in these high elevation forests, there is no basis for assuming that forest structure and fuel conditions are outside of the historic range of variability for this habitat. Fire occurrence in these high elevation sites is highly dependent on drought, which often results from La Nina events. In comparison with lower elevation ponderosa pine forests of the Front Range, fire is less dependent on increased fuel production following wet El Nino events.$
CL 1404
AU Sherrod, S.K.
DT 1999
TI A multiscale analysis of the Northern Pocket Gopher (Thomomys talpoides) in the Alpine, Niwot Ridge, CO
SO Ph.D. dissertation, University of Colorado. 141 pp.
DE NWTLTER
AB None
$
CL1448
AU Sherrod, S.K.
; Seastedt, T.R.
DT 2001
TI Effects of the northern pocket gopher (Thomomys talpoides) on alpine soil characteristics, Niwot Ridge, CO
SO Biogeochemistry vol. 55 (2).  pp.195-218
DE NWTLTER
AB Effects of the northern pocket gopher (Thomomys talpoides) on surface soil characteristics were examined at the alpine site of Niwot Ridge, CO. We measured erosion of soil from gopher mounds and compared the characteristics of gopher mound (disturbed) and undisturbed soils in two major plant community types. Our measurements of erosion indicate long-term susceptibility of gopher-disturbed soils to redistribution by water and/or wind in this ecosystem. Ecosystem heterogeneity introduced by the gopher is reflected in significantly lower SOM in gopher mounds than in surrounding undisturbed soils, a characteristic which appears to be causally associated with other effects of gopher disturbance including changes in soil texture and significantly lower clays, total C, total N, total P, and labile P. In contrast to plant-available P, NO-3 was higher and steadily increased for the short term in both gopher mound soils and those beneath the mounds. These pools of NO-3 then decreased to pre-disturbance levels by the following spring. Collectively our results indicate that, through the physical manipulation of soil and subsequent effects on soil resources, the northern pocket gopher functions as an agent of increased ecosystem heterogeneity and soilmass and nutrient redistribution at Niwot Ridge.
$
CL1472
AU Shiels, A.B.
; Sanford, R.L.
DT 2001
TI Soil nutrient differences between two krummholz-form tree species and adjacent alpine tundra
SO GEODERMA 102 (3-4) pp205-217
DE krummholz
; alpine
; tundra
; soil nutrients
; soil phosphorus
; organic horizon 
; COLORADO FRONT-RANGE
; ROCKY MOUNTAINS
; NIWOT-RIDGE
; PHOSPHORUS
; ISLANDS
; USA
; PLANTS
; ECOSYSTEMS
AB Above treeline at Goliath Peak, Colorado, Pinus aristata (bristlecone pine) and Picea engelmannii (Engelmann spruce) grow as krummholz tree forms. Due to the harsh alpine climate, these trees are dwarfed in size (approximately 0.5 to 3.0m tall) and root along a horizontal stem. Soil nutrients, including carbon, nitrogen, and phosphorus fractions were examined to 10-cm depth beneath P. aristatakrummholz and P. engelmannii krummholz, as well as from adjacent, undisturbed alpine soils. Plant available phosphorus was higher under P. engelmannii than P. aristata, suggesting that although these two species exist in the same environment, they have a different effect on the availability of labile soil phosphorus. Mineral soils under P. aristata were not significantly different than under P. engelmannii for total carbon, total nitrogen, and total phosphorus. Soil phosphorus differences are important in this ecosystem because of the proposed P limitation in some alpine ecosystems. (C) 2001 Elsevier Science B.V. All rights reserved.
$
CL 0833
AU Short, S.K.
; Elias, S.A.
DT 1984
TI Holocene vegetational history of the Colorado Front Range
SO 6th International Palynological Conference, University of Calgary, Calgary,
 Alberta. Abstract. 153 pp.
DE Paleoecology
; Long-Term Ecological Research Program
; Conifers
; Angiosperms
; Climate - Discussion of
; Pollen
; Chronology

2000
AB None
$
CL 0833a
AU Short, S.K.
; Elias, S.A.
DT 1987
TI New pollen and beetle analyses at the Mary Jane site, Colorado: evidence for
 late glacial tundra conditions
SO Geological Society of America Bulletin, 98:540-548
DE article
; paleoecology
; Long-Term Ecological Research Program
; angiosperms
; insects
; pollen
; timberline
; NWTLTER
AB None
$
CL 0834
AU Short, S.K.
; Nichols, H.
; Briggs, W.
; Elias, S.A.
; Andrews, J.T.
DT 1983
TI Paleoenvironmental studies in the Colorado Front Range
SO University of Colorado Long-Term Ecological Research Data Report, 83/4. 38
 pp.
DE Paleoecology
; Long-Term Ecological Research Program
; Conifers
; Angiosperms
; Climate - Discussion of
; Pollen
AB None
$
CL 0832a
AU Short, S.K.
DT 1985
TI Palynology of Holocene sediments, Colorado Front Range: vegetation and
 treeline changes in the subalpine forest
SO American Association Stratigraphic Palynologist Contribution Series, 16:7-30
DE Paleoecology
; Long-Term Ecological Research Program
; Indian Peaks Region
; Climate - Discussion of
; Lake
; Sediment
; Pollen
; Succession
; NWTLTER
AB None
$
CL 0839
AU Shulls, W.A.
; Mancinelli, R.L.
DT 1982
TI Comparative study of metabolic activities of bacteria in three ecoregions of
 the Colorado Front Range, U.S.A.
SO Arctic and Alpine Research, 14:53-58
DE Microbiology
; Long-Term Ecological Research Program
; Niwot Ridge
; A-1 Climate Station
; Decomposition
; Metabolism
; NWTLTER
AB None
$
CL 0837
AU Shulls, W.A.
DT 1976
TI Microbial populations of the Colorado alpine tundra
SO Arctic and Alpine Research, 8:387-391
DE Microbiology
; University of Colorado
; Niwot Ridge
; Community
; Demography
; Decomposition
; Metabolism
AB None
$
CL 0838
AU Shulls, W.A.
DT 1982
TI A review of some aspects of bacteriological decomposition of plant litter
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37: 138-147
DE Microbiology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Decomposition
; Metabolism
; NWTLTER
AB None
$
CL 0840
AU Shushan, S.
; Flock, J.W.
; Bonde, E.K.
DT 1983
TI Plant voucher specimens from Niwot Ridge
SO University of Colorado Long-Term Ecological Research Working Paper, 83/3. 8
 pp.
DE Data report
; Flora
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Angiosperms
; Lichens
; Bryophytes
AB None
$
CL 1300
AU Sievering H.
; Rusch D.
; Marquez L.
DT 1996
TI Nitric acid, particulate nitrate and ammonium in the continental free
 troposphere: Nitrogen deposition to an alpine tundra ecosystem
SO Atmospheric Environment 30 (14):2527-2537
DE NWTLTER
; deposition
; ecosystem
; nitrogen
; nitric acid
; tundra
; tropospheric
AB Atmospheric sampling of nitric acid vapor, particulate nitrate and 
 ammonium has been ongoing at a 3540m a.s.l. alpine tundra site on Niwot 
 Ridge, Colorado, since January 1993. These nitrogen (N) species data,
 in conjunction with meteorological data, N data at a 3020m a.s.l. subalpine
 site, and back-trajectory information, show that over 90% of the sampling
 was obtained under free tropospheric but, apparently, N-enriched
 conditions. Seasonal concentration and estimated N dry deposition trends
 are presented. Dry plus wet atmospheric N loading is found to provide
 2.5-3 kg N per ha of new, available N to tundra plants during the growing
 season (mid-May to mid-September), of which 50%, or more, is dry deposited.
 During the eight-month, nongrowing season about 5 kg N per ha is wet plus 
 dry deposited to the aggrading snowpack or dormant tundra plants. Up to 
 half of this nongrowing season N loading is made available to growing
 tundra plants by atmospheric deposition of, primarily, anthropogenically
 derived N. This annual input of new, available N to nutrient N-limited
 tundra plants may be compared with the dominant pathway for plant N
 availability at Niwot Ridge-net mineralization of 10-12 kg N per ha per
 year recycled through the soil. The ratio of atmospheric N deposition to
 net N mineralization, presently approaching 0.5, is higher at the Niwot
 Ridge alpine tundra ecosystem than at most other ecosystems in the 
 continental U.S.
$
CL1446
AU Sievering, H.
; Kelly, T.
; McConville, G.
; Seibold, C.
; Turnipseed, A.
DT 2001
TI Nitric acid dry deposition to conifer forests: Niwot Ridge spruce-fir-pine study
SO Atmospheric Environment vol.35. pp.3851-3859
DE Nitric acid
; Dry deposition
; Conifer forests
; Sprice
; Fir
; Pine
AB The dry deposition velocity of nitric acid, Vd(HNO3), over a 12-m (mean height) spruceùfir forest at Niwot Ridge, Colorado was estimated during 13 daytime periods using the flux-gradient approach. Turbulence intensity at this site is high (mean u* of 0.65 m s-1 with u of 2.9 m s-1) and contributed to the large observed Vd(HNO3). The overriding contributor is identified to be the small aerodynamic needle width of the conifer trees. Two cases had inflated Vd(HNO3) due to height-differentiated nitric acid loss to soil-derived particle surfaces. Not considering these cases, the mean Vd(HNO3) was 7.6 cm s-1. The mean laminar boundary layer resistance (Rb) was found to be 7.8 s m-1 (of similar magnitude to that of the aerodynamic resistance, 8.5 s m-1). The data-determined Rb is bracketed by two theoretical estimates of the mean Rb, 5.9 and 8.6 s m-1, that include consideration of the small canopy length scale (aerodynamic needle width), 1 mm or less, at this conifer forest. However, the poor correlation of data-determined Rb values with both sets of theoretical estimates indicates that measurement error needs to be reduced and/or improved formulations of theoretical Rb values are in order. The large observed Vd(HNO3) at this conifer forest site is attributed to high turbulence intensity, and, especially, to small aerodynamic needle width.
$
CL 0840a
AU Sievering, H.
; Ahnberg, P.
DT 1987
TI Estimated annual dry deposited fluxes of several elements in long-range
 transported ambient air aerosol particles over the Niwot Ridge area during
 1986
SO University of Colorado Long-Term Ecological Research Data Report 87/3. 11 pp
DE Data Report
; Atmospheric Sciences
; Long-Term Ecological Research Program
; Acid Deposition
; Atmospheric Chemistry
; Wind
; Precipitation
; C-1 Climate Station
; Saddle (Niwot Ridge)
AB None
$   
CL 1378
AU Sievering, H.
DT 1999
TI Nitrogen deposition and carbon sequestration
SO Nature 400:629
DE NWTLTER
; nitrogen deposition
; carbon sequestration
AB None
$
CL 1433
AU Sievering, H.
DT 2001
TI Atmospheric chemistry and deposition
SO Chapter 3 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 0840b
AU Sievering, H.
; Braus, J.
; Caine, J.
DT 1989
TI Dry deposition of nitrate and sulfate to coniferous canopies in the Rocky
 Mountains
SO In: Transactions, Effects of Air Pollution on Western Forests (R.K. Olson
 and A.S. Lefohn, eds.).  Air and Waste Management Association, Anaheim,
 California, pp. 171-175
DE atmospheric science
; Long-Term Ecological Research Program
; C-1
; conifers
; acid deposition
; atmospheric chemistry
; nitrogen compounds
; nutrients
; NWTLTER
AB None
$
CL 1231
AU Sievering, H.,
; Burton, D.
; Caine, N.
DT 1992
TI Atmospheric loading of nitrogen to alpine tundra in the Colorado Front Range
SO Global Biogeochemical Cycles 6: 339-346
DE NWTLTER
; atmospheric deposition
; nitrogen
; biogeochemistry
; nutrient cycling
; Niwot Ridge
AB Dry deposition of atmospheric nitrogen gas and aerosol species was estimated
 for the alpine tundra of Niwot Ridge, 3525 m elevation in the Colorado
 Rockies. Comparisons, for the 4-month long growing season and the remaining 8
 months of the year, were made with wet deposition and throughfall incident
 measurements taken during 1987-1989. Dry deposition of N to the tundra is
 e
2000
stimated to be equal or slightly greater than its wet deposition. During the
 mid-May to mid-September growing season, atmospheric N deposition is > 1.0 mg
 N/m^2/d directly from the atmosphere with a similar amount contributed
 indirectly as NO3-N in snowmelt water as a result of dry and wet deposition to
 the winter snowpack. The total N deposition to Niwot Ridge tundra during the
 growing season of about 2 mg N/m^2/d may be compared to an earlier measurement
 of dry plus fog deposition (1-2 mg N/m^2/d) to a subalpine coniferous canopy
 at Niwot Ridge. Nitrate yields from two small drainage basins at Niwot Ridge
 match these fluxes. Seven years of record from an unvegetated glacial cirque
 suggest an average yield from the alpine of 0.7 mg N/m^2/d. The equivalent
 estimate for a basin with 50% tundra vegetation cover is 0.4 mg N/m^2/d. The
 contrast in these two estimates of daily averaged N yields for the entire year
 suggests the retention of nearly 1 mg N/m^2/d during the growing season in the
 more vegetated basin. The sink for this N could be tundra soil and vegetation
 where biological activity is often limited by the availability of N.
$
CL 0841
AU Sievers, R.E.
; Roberts, J.M.
; Fehsenfeld, F.C.
DT 1982
TI Measurement of monoterpene hydrocarbons in rural atmospheres
SO Presented before the division of Environmental Chemistry, American Chemical
 Society, Kansas City, MO, September 1982
DE Atmospheric sciences
; NOAA - Aeronomy Lab
; C-1 Climate Station
; Atmospheric Chemistry
AB None
$
CL 0841b
AU Silverstein, M.C.
; Greenland, D.
DT 1991
TI Wet acid deposition in Colorado in the 1985 hydrologic year
SO Physical Geography 12(1): 55-71
DE article
; atmospheric science
; climatology
; University of Colorado
; Niwot Ridge
; acid deposition
; NWTLTER
AB None
$
CL 0841a
AU Silverstein, M.C.
DT 1988
TI Climatology of wet acid deposition in Colorado
SO M.A. thesis, University of Colorado, Boulder, 153 pp
DE thesis
; atmospheric science
; climatology
; University of Colorado
; Niwot Ridge
; acid deposition
; NWTLTER
AB None
$
CL 0842
AU Simkins, E.C.
DT 1931
TI The alpine flora of Mt. Niwot, Colorado
SO M.A. thesis. University of Colorado, Boulder. 68 pp.
DE Ecology
; History
; University of Colorado
; Niwot Ridge
; Angiosperms
AB None
$
CL 0843
AU Simms, H.R.
DT 1965
TI Fungi of two spruce-fir forests in Northern and Southern Colorado
SO Ph.D. dissertation, University of Colorado, Boulder. 94 pp.
DE Dissertation
; Flora
; Ecology
; University of Colorado
; Taxonomy & systematics
; Boulder Watershed and Rainbow Lakes
; Fungi
; Conifers
; Disease
AB None
$
CL 0848
AU Sinclair, R.A. (ed.)
DT 1983
TI Long-Term Ecological Research Data Management Workshop held at
 Urbana-Champaign, Illinois. November 22-23, 1982
SO Illinois State Water Survey Miscellaneous Publication, 72. 24 pp.
DE Technical report
; Ecology
; Management
; Long-Term Ecological Research Program
; NWTLTER
AB None
$
CL 0849
AU Slaymaker, O.
DT 1984
TI High mountain environments
SO Progress in Physical Geography, 8:118-128
DE Overview
; Ecology
; Niwot Ridge
AB None
$
CL 0849a
AU Smith, C.C.
; Hamrick, J.L.
; Kramer, C.L.
DT 1988
TI The effects of stand density on frequency of filled seeds and fecundity in
 lodgepole pine (Pinus contorta Dougl.)
SO Canadian Journal of Forest Research 18:453-460
DE article
; ecology
; Mountain Research station
; conifers
; community
; demography
; germination
; population
; seed
; tree
AB None
$
CL 1401
AU Soranno, P.A.
; Webster, K.E.
; Riera, J.L.
; Kratz, T.K.
; Baron, J.S.
; Bukaveckas, P.A.
; Kling, G.W.
; White, D.S.
; Caine, N.
; Lathrop, R.C.
; Leavitt, P.R.
DT 1999
TI Spatial variation among lakes within landscapes: Ecological organization    along lake chains  
SO Ecosystems 2:395-410. 
DE None
AB None
$ 
CL 1370
AU Soranno, P.A. 
;Webster, K.E.
; Riera, J.L.
; Kratz, T.K.
; Baron, J.S.
; Bukaveckas, P.A.
; Kling, G.W.
; White, D.S.
; Caine, N.
; Lathrop, R.C.
; Leavitt, P.R.
DT 1999
TI Spatial variation among lakes within landscapes: Ecological organization
 along lake chains
SO Ecosystems 2:395-410
DE NWTLTER
; landscape position
; lake variability
; lake districts
; synchrony
; coherence
; north temperate lakes;
; lake chains
; lake order
; lake number
; water residence time
AB Although limnologists have long been interested in regional patterns in lake
 attributes, only recently have they considered lakes connected and organized
 across the landscape, rather than as spatially independent entities. Here we
 explore the spatial organization of lake districts through the concept of 
 landscape position, a concept that considers lakes longitudinally along
 gradients of geomorphology and hydrology. We analyzed long-term chemical
 and biological data from nine lake chains (lakes in series connected through
 surface or groundwater flow) from seven lake districts of diverse hydrologic
 and geomorphic settings across North America. Spatial patterns in lake 
 variables driven by landscape position were surprisingly common across lake 
 districts and across a wide range of variables. On the other hand, temporal 
 patterns of lake variables, quantified using synchrony, the degree to which 
 pairs of lakes exhibit similar dynamics through time, related to landscape 
 position only for lake chains with lake water residence times that spanned 
 a wide range and were generally long (close to or greater than 1 year).  
 Highest synchrony of lakes within a lake chain occurred when lakes had short
 water residence times. Our results from both the spatial and temporal analyses
 suggest that certain features of the landscape position concept are robust
 enough to span a wide range of seemingly disparate lake types. The strong spatial
 patterns observed in this analysis, and some unexplained patterns, suggest the 
 need to further study these scales and to continue to view lake ecosystem spatially,
 longitudinally, and broadly across the landscape.
$
CL 0856aa
AU Southwick, C.H.
; Golian, S.C.
; Whitworth, M.R.
; Halfpenny, J.C.
; Brown, R.
DT 1986
TI Population density and fluctuations of pikas (Ochotona princeps) in Colorado
SO Journal of Mammalogy, 67:149-153
DE article
; ecology
; Long-Term Ecological Research Program
; Saddle
; lagomorphs
; snow
; population
; behavior
; NWTLTER
AB None
$
CL 0853
AU Southwick, C.H.
; Golian, S.C.
; Whitworth, M.R.
; Halfpenny, J.C.
DT 1984
TI Population studies of pika: a theory of population stability
SO American Zoologist, 24: 88A.  Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Demography
; Lagomorphs
AB None
$
CL 0855
AU Southwick, C.H.
; Whitworth, M.R.
; Golian, S.
; Halfpenny, J.C.
DT 1984
TI Population functions of pikas in Central Colorado
SO New Mexico Journal of Science, 24(1):80. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Demography
; Lagomorphs
AB None
$
CL 0856
AU Southwick, C.H.
; Whitworth, M.R.
; Golian, S.C
; Halfpenny, J.C.
DT 1984
TI Relative stability of pika populations (Ochotona princeps) in Colorado
SO Bulletin of Ecological Society of America, 65(2):95. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Lagomorphs
; Demography
AB None
$
CL 0854
AU Southwick, C.H.
; Golian, S.
; Whitworth, M.R.
; Halfpenny, J.H.
DT 1985
TI Population patterns of pika: A theory of population stability
SO In: Fuller, W.A., Nietfield, M.T., and Harris, M.A. (eds.), Abstracts of
 Papers and Posters, Fourth International Theriological Congress, Edmonton,
 13-20 August, 1985. Abstract No. 589, Session W08. Abstract
DE Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Demography
; Lagomorphs
; Abstract
AB None
$
CL 0856a
AU Spence, J.R.
; Flock, J.W.
DT 1988
TI Alpine mosses of the Indian Peaks region, Front Range, Colorado
SO Mountain Research Station, University of
2000
 Colorado Natural History Paper 2,
 19 pp
DE Technical Report
; Taxonomy
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Mosses
; Pteropsida
AB None
$
CL 0860
AU Stein, J.R.
; Amundsen, C.C.
DT 1967
TI Studies on snow algae and fungi from the Front Range of Colorado
SO Canadian Journal of Botany, 45:2034-2046
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Algae
; Fungi
; Snow
; Community
AB None
$   
CL 1346
AU Steltzer, H.
; Bowman, W.D.
DT 1998
TI Differential influence of plant species on soil nitrogen transformations within
 moist meadow alpine tundra
SO Ecosystems 1:464-474
DE NWTLTER
; plant species effect
; net nitrogen mineralization
; net nitrification
; alpine tundra
; phenolics
; carbon:nitrogen ratio
; fine-root production
AB Plant species can influence nitrogen (N) cycling indirectly through the 
 feedbacks of litter quality and quantity on soil N transformation rates. 
 The goal of this research was to focus on small-scale (within-community) 
 variation in soil N cycling associated with two community dominants of the 
 moist meadow alpine tundra. Within this community, the small-scale patchiness 
 of the two most abundant species (Acomastylis rossii and Deschampsia 
 caespitosa) provides natural variation in species cover within a relatively 
 similar microclimate, thus enabling estimation of the effects of plant 
 species on soil N transformation rates.  Monthly rates of soil N 
 transformations were dependent on small-scale variation in both soil 
 microclimate and species cover. The relative importance of species cover 
 compared with soil microclimate increased for months 2 and 3 of the 3-month 
 growing season. Growing-season net N mineralization rates were over ten 
 times greater and nitrification rates were four times greater in Deschampsia 
 patches than in Acomastylis patches. Variability in litter quality 
 [carbon:nitrogen (C:N) and phenolic:N], litter quantity (aboveground and 
 fine-root production), and soil quality (C:N) was associated with three 
 principal components. Variability between the species in litter quality
 and fine-root production explained 31% of the variation in net N mineralization
 rates and 36% of net nitrification rates. Site variability across the landscape
 in above-ground production and soil C:N explained 33% of the variation in net
 N mineralization rates and 21% of net nitrification rates. Within the moist 
 meadow community, the high spatial variability in soil N transformation rates 
 was associated with differences in the dominant species' litter quality and 
 fine-root production. Deschampsia-dominated patches consistently had greater 
 soil N transformation rates than did Acomastylis-dominated patches across 
 the landscape, despite site variability in soil moisture, soil C:N, and 
 aboveground production. Plant species appear to be an important control 
 of soil N transformation in the alpine tundra, and consequently may influence 
 plant community structure and ecosystem function.
$
CL 0863
AU Stinson, N., Jr.
DT 1978
TI Seasonal survival rates in subalpine mammals
SO Journal Colorado-Wyoming Academy of Sciences, 10(1):43. Abstract
DE Abstract
; Ecology
; University of Colorado
; Mountain Research Station - Location
; Rodents
; Snow
; Demography
; Phenological (seasonal)
AB None
$
CL 0862
AU Stinson, N.S.
DT 1977
TI Species diversity, resource partitioning, and demography of small mammals in
 a subalpine deciduous forest
SO Ph.D. dissertation, University of Colorado. 238 pp.
DE Dissertation
; Ecology
; University of Colorado
; Mountain Research Station - Location
; Rodents
; Demography
; Diversity
; Food Habits
; Snow
AB None
$
CL 0864
AU Street, F.A.
DT 1973
TI A study of tors in the Front Range of the Rocky Mountains in Colorado, with
 special reference to their value as an indicator of nonglaciation
SO M.A. thesis, University of Colorado, Boulder. 241 pp.
DE Thesis
; Geomorphology
; Institute of Arctic and Alpine Research
; Altitude
; Periglacial
; Indian Peaks Region
; Mount Evans and Guanella Pass Region
; Rocky Mountain National Park - Location
; Niwot Ridge
AB None
$
CL 0865
AU Sturgeon, K.B.
DT 1980
TI Evolutionary interactions between the mountain pine beetle, Dendroctonus
 ponderosae Hopkins, and its host trees in the Colorado Rocky Mountains
SO Ph.D. dissertation, University of Colorado, Boulder.  160 pp.
DE Dissertation
; Ecology
; University of Colorado
; Mountain Research Station - Location
; Conifers
; Insects
; Demography
; Distribution
; Parasites
AB None
$
CL 0866
AU Suanraksa, S.
DT 1960
TI Differences in metabolic rate between grasshoppers from high and low
 altitudes
SO M.S. thesis, University of Colorado, Boulder. 61 pp.
DE Thesis
; Biology
; University of Colorado
; Mount Evans and Guanella Pass Region
; B-1 Climate Station
; Insects
; Metabolism
; Rollins Pass and Tolland
; A-1 Climate Station
; D-1 Climate Station
; Climate - Discussion of
AB None
$
CL 1573
AU Suding, K.N.
; Collins, S.L.
; Gough, L.
; Clark, C.
; Cleland, E.E.
; Gross, K.L.
; Milchunas, D.G.
; Pennings, S.
DT 2005
TI Functional- and abundance-based mechanisms explain diversity loss due to N fertilization
SO Proceedings of the National Academy of Sciences of the United States of America vol. 102 (12) pp. 4387-4392
DE NWTLTER
; Conference Proceedings
AB None
$
CL 1567
AU Suding, K.N.
; Larson, J.
; Thorsos, E.
; Steltzer, H.
; Bowman, W.B.
DT 2004
TI Species effects on resource supply rates: do they influence competitive interactions?
SO Plant Ecology vol. 175 pp. 47-58
DE NWTLTER
AB None.
$
CL 0867a
AU Swanson, F.J.
; Kratz, T.K.
; Caine, N.
; Woodmansee, R.G.
DT 1988
TI Landform effects on ecosystem patterns and processes
SO BioScience, 38(2):92-98
DE Journal
; Geomorphology
; Geoecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Landslide
; Glacier
; Stream
; Lake
; Periglacial
; NWTLTER
AB None
$
CL 0868
AU Sweeten, J.C.
DT 1984
TI Applications of the precipitation-runoff modeling system to the Boulder
 alpine watershed
SO M.S. thesis, University of Colorado, Boulder. 119 pp.
DE Thesis
; Model
; Hydrology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Lake
; Precipitation
; Snow
; Stream
; NWTLTER
AB None
$
CL 0868a
AU Swift, L.W., Jr.
; Ragsdale, H.L.
DT 1985
TI Meteorological data stations at Long-Term Ecological Research sites
SO In: Hutchison, B.A., and Hicks, B.B. (eds.), Proceedings of Forest
 Environmental Measurements Conference.  Oak Ridge, TN, October 1983. Reidel,
 Dordrecht, Holland, 25-37
DE Climatology
; Long-Term Ecological Research Program
; A-1 to D-1 Climate Stations
; Climate - Discussion of
AB None
$
CL 0868b
AU Tans, P.P.
; Conway, T.J.
; Nakazawa, T.
DT 1989
TI Latitudinal distribution of the sources and sinks of atmospheric carbon
 dioxide derived from surface observations and an atmospheric transport model
SO Journal of Geophysical Research 94:5151-5172
DE article
; atmospheric science
; University of Colorado
; NOAA - Geophysical Monitoring for Climatic Change
; C-1
; atmospheric chemistry
; carbon dioxide
AB None
$
CL 0869
AU Taussig, W.H.
DT 1962
TI An ecological study of Formica neorufibarbis gelida Wheeler in the alpine
 tundra of Colorado
SO M.S. thesis, University of Colorado, Boulder. 91 pp.
DE Thesis
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Insects
; Altitude
; Distribution
; Habitat
AB None
$
CL 0869a
AU Taylor, M.D.
; Halfpenny, J.C.
; Heffernan, M.
; Rink, L.
DT 1987
TI Community phenology of the Saddle, Niwot Ridge, Colorado
SO University of Colorado Long-Term Ecological Research Data Report 87/6. 54 pp
DE Data Report
; Ecology
; Long-Term Ecological Research Program
; Saddle (Niwot Ridge)
; Angiosperms
; Snow
; Map
; Phenology
AB None
$
CL 1240
AU Taylor, R.V.
; Seastedt, T.R.
DT 1994
TI Short- and long-term patterns of soil moisture in alpine tun
2000
dra
SO Arctic and Alpine Research 26(1):14-20
DE NWTLTER
; Niwot Ridge
; Saddle
; soil moisture
; time domain reflectometry
; climate
AB Time domain reflectometry (TDR), a nondestructive technique for monitoring
 water content of soils, was used to measure volumetric soil moisture in three
 different communities in the alpine tundra during the summer of 1992. Data
 were converted to gravimetric estimates in order to allow comparison with 20
 yr of records of gravimetric data, some of which date back to 1953. Analysis
 for growing-season trends indicated progressive depletion of soil moisture in
 all three community types studied. Using a linear model, mesic meadows showed
 the strongest seasonal decline and wet meadows the weakest. Curvilinear fits
 of the data suggested midsummer minima in xeric and mesic meadows and a
 midsummer maximum in wet meadows. Average summer soil moisture values for
 xeric meadows during the 1953-1964 interval were lower than those made in
 later years. This result may reflect sample site differences, but is
 consistent with a directional trend in increasing precipitation, but not
 growing season (June-August) rainfall; this pattern was only discernible with
 the 20 yr data set.
$
CL 1506
AU Taylor, S.
; Feng, X.
; Williams, M.W.
; McNamara, J.
DT 2002
TI How isotopic fractionation of snowmelt affects hydrograph separation
SO Hydrologic Processes v. 16 pp. 3683-3690
DE NWTLTER
AB None
$
CL 1301
AU Theodose T.A.
; Jaeger C.H.
; Bowman W.D.
; Schardt J.C.
DT 1996
TI Uptake and allocation of 15N in alpine plants: implications for the
 importance of competitive ability in predicting community structure in
 a stressful environment
SO Oikos 75: 59-66
DE NWTLTER
; alpine tundra
; nitrogen limitation
; nitrogen
; biomass
; plant competition
AB Several potential components of competitive ability were determined
 for 13 plant species in a N-limited alpine moist meadow community in
 order to determine if competition had an influence on relative abundance
 in this stressful environment. The components of competitive ability
 examined were 15N uptake rate, 15N allocation, whole plant biomass,
 root:shoot ratio, and tissue N concentrations. It was hypothesized that
 15N uptake rate would be the component most correlated with relative 
 abundance. However, 15N uptake rate was negatively correlated with
 percent cover in  the community. In contrast, whole plant biomass
 and root:shoot ratio were positively correlated with relative abundance.
 Tissue N concentrations and 15N allocation were not important predictors
 of relative abundance. These results suggest that in a harsh environment,
 high resource uptake rates are not indicative of competitive ability, 
 but may instead be a mechanism by which rare species are able to coexist
 with competitive dominants.
$
CL 1274
AU Theodose, T.A.
DT 1995
TI Interspecific plant competition in alpine tundra
SO Ph.D. dissertation, University of Colorado, Boulder. 160 pp.
DE NWTLTER
; plant communities
; community dynamics
; Niwot Ridge
; competitive interactions
; allocation
; nutrients
; nitrogen
; biogeochemistry
AB The goal of this research was to demonstrate the importance of 
 interspecific competition in influencing community composition
 (abundance and distribution) in a stressful environment. The 
 responses of plant species abundance and diversity to 
 fertilization were investigated in two alpine plant communities,
 a dry meadow and a wet meadow. Dominance shifts following fertilization
 were more pronounced in the dry meadow than in the wet meadow, leading
 to an increase in diversity in the dry meadow and a decrease in the
 wet meadow. The relationship between abundance and certain aspects of
 competitive ability was further demonstrated in an alpine moist 
 meadow. Biomass and root:shoot ratio were positively correlated with
 abundance. The influence of competition on the distribution of the
 moist meadow dominant Deschampsia caespitosa was investigated in a dry
 meadow community. Pot experiments established that traits that confer
 competitive ability were exhibited to a greater extent in Deschampsia
 than in the dry meadow dominant Kobresia myosuroides. However, in the
 field Deschampsia survival and reproduction were greater in plots with
 Kobresia removed relative to plots with Kobresia present. Soil moisture
 results suggested that competition was for water. Thus Kobresia may 
 competitively displace Deschampsia from the dry meadow.
$
CL 1329
AU Theodose, T.A.
; Bowman, W.D.
DT 1997
TI Nutrient availability, plant abundance, and species diversity in two alpine
 tundra communities. 
SO Ecology 78: 1861-1872
DE NWTLTER
; species diversity
; nitorgen
; phosphorus
AB None
$
CL 1319
AU Theodose, T.A.
; Bowman, W.D.
DT 1997
TI The influence of interspecific competition on the distribution of an 
 alpine graminoid: evidence for the importance of plant competition in an 
 extreme environment.
SO Oikos. 79:101-114.
DE NWTLTER
; plant competition
; alpine 
; Kobresia myosuroides
; Deschampsia caespitosa
AB The importance of interspecific competition to plant distribution
 in an unproductive environment was investigated for two alpine
 tundra graminoids that differed in community of origin, Kobresia
 myosuroides from a resource poor dry meadow and Deschampsia caespitosa
 from a more resource rich moist meadow. It was hypothesized that
 Deschampsia is absent from the resource poor dry meadow due to competitive
 displacement by Kobresia, rather than low resource availability. A
 removal experiment was performed in the dry meadow, where Deschampsia
 growth, physiology, and mortality in response to both vegetation removal
 and N additions were examined. Water availability was monitored
 throughout the experiment. The effect of removal on Deschampsia was 
 more pronounced than that of N addition. Removal resulted in a significant
 decrease in Deschampsia mortality, and significant increases in Deschampsia
 shoot and root biomass, tillering, biomass per tiller, root:shoot ratio,
 root N concentrations, water-use-efficiency and flowering. Soil moisture
 differences between intact and removal plots suggest that Kobresia is
 able to competitively displace Deschampsia from the dry meadow by reducing
 water levels below which Deschampsia can grow and reproduce. A second
 experiment, conducted in removal plots only, examined the mortality, 
 growth, and physiology of Deschampsia and Kobresia in response to variations
 in neighbor and N availability. Kobresia exhibited no adverse response
 to competition with Deschampsia, even under high N conditions. These
 results demonstrate that a species of a resource poor community is
 capable of competitively displacing a species from a more resource rich
 community. Since this experiment was conducted in alpine tundra, these
 results illustrate that competition can be an important force structuring
 plant community composition in an extreme environment.
$
CL 0871
AU Thilenius, J.F.
DT 1975
TI Alpine range management in the Western United States--principles, practices,
 and problems: the status of our knowledge
SO U.S.D.A. Forest Service Research Paper, RM-157. 32 pp.
DE Technical report
; Ecology
; Management
; Niwot Ridge
; Plant
; Animals
; Habitat
AB None
$
CL 1335
AU Thomas B.D.
; Bowman W.D.
DT 1998
TI Influence of N2-fixing Trifolium on plant species composition
 and biomass production in alpine tundra
SO Oecologia 115:26-31
DE NWTLTER
; alpine tundra
; biotic interactions
; community structure
; nitrogen
; Trifolium
AB Alpine Trifolium species have high rates of symbiotic N2-fixation
 which may influence the abundance and growth of plant species growing
 near them. The potential for facilitative effects on plant abundance
 and growth in dry meadow alpine tundra of Niwot Ridge, Colo., characterized
 by low resource availability, was investigated by measuring soil N,
 aboveground biomass production, and plant species composition in patches
 of Trifolium dasyphy
2000
llum and surrounding tundra. Extractable inorganic
 N was more than twofold greater and extractable P was 27% lower in
 Trifolium patches than in surrounding tundra. Aboveground production
 was twofold greater in Trifolium patches than in surrounding tundra.
 However, the difference was largely due to the production of T. dasyphyllum
 relative to the non-Trifolium component of biomass, which was not different
 between the Trifolium patches and surrounding tundra. In the Trifolium
 patches, the proportion of graminoid biomass was lower while the proportion
 of forb biomass was higher relative to surrounding tundra. Although the
 abundance of some species was positively associated with the presence of
 Trifolium, other species were less abundant, possible due to increased
 competition for P and differential abilities of alpine species to respond
 to increased N availability. Trifolium may exert both facilitative and
 inhibitive effects on dry meadow alpine species and, in the process,
 substantially influence the spatial heterogeneity in community structure
 and primary production.
$
CL 0886
AU Thorn, C.E.
; Darmody, R.G.
DT 1985
TI Grain-size sampling and characterization of eolian lag surfaces within
 alpine tundra, Niwot Ridge, Front Range, Colorado, U.S.A.
SO Arctic and Alpine Research, 17:443-450
DE Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Wind
; Soil
; Soil sciences
AB None
$
CL 0881
AU Thorn, C.E.
DT 1980
TI Alpine bedrock temperatures: An empirical study
SO Arctic and Alpine Research, 12:73-86
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Temperature
; Soil
AB None
$
CL 0882
AU Thorn, C.E.
DT 1982
TI Gopher disturbance: its variability by Braun-Blanquet vegetation units in
 the Niwot Ridge alpine tundra zone, Colorado Front Range, U.S.A.
SO Arctic and Alpine Research, 14:45-51
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Rodents
; Soil
; Community
; Demography
; Distribution
; Angiosperms
; Disturbances
AB None
$
CL 0874
AU Thorn, C.E.
DT 1975
TI Influence of late-lying snow on rock-weathering rinds
SO Arctic and Alpine Research, 7:373-378
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Snow
; Periglacial
AB None
$
CL 0887
AU Thorn, C.E.
; Hall, K.
DT 1980
TI Nivation: An arctic-alpine comparison and reappraisal
SO Journal of Glaciology, 25(91):109-124
DE Geomorphology
; Niwot Ridge
; Snow
; Periglacial
; Water
AB None
$
CL 0878
AU Thorn, C.E.
DT 1978
TI The geomorphic role of snow
SO Annals of the Association of American Geographers, 68:414-425
DE Geomorphology
; Niwot Ridge
; Snow
; Periglacial
; Water
AB None
$
CL 0885
AU Thorn, C.E.
; Darmody, R.G.
DT 1985
TI Grain-size distribution of the insoluble component of contemporary eolian
 deposits in the alpine zone, Front Range, Colorado, U.S.A.
SO Arctic and Alpine Research, 17:433-442
DE Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Wind
; Soil
; Soil sciences
AB None
$
CL 0876
AU Thorn, C.E.
DT 1976
TI Quantitative evaluation of nivation in the Colorado Front Range
SO Geological Society of America Bulletin, 87:1169-1178. Reprinted in: Ives,
 J.D. (ed.), 1980: Geoecology of Colorado Front Range. Boulder: Westview Press,
 164-173
DE Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Snow
; Periglacial
; Water
AB None
$
CL 0873
AU Thorn, C.E.
DT 1974
TI Nivation: a reappraisal
SO Geological Society of America Abstracts with Programs, 6(7):987. Abstract
DE Abstract
; Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Snow
; Periglacial
; Water
AB None
$
CL 0872
AU Thorn, C.E.
DT 1974
TI An analysis of nivation processes and their geomorphic significance, Niwot
 Ridge, Colorado Front Range
SO Ph.D. dissertation, University of Colorado, Boulder. 351 pp.
DE Dissertation
; Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Snow
; Periglacial
; Water
AB None
$
CL 0879
AU Thorn, C.E.
DT 1979
TI Bedrock freeze-thaw weathering regime in an alpine environment, Colorado
 Front Range
SO Earth Surface Processes, 4:211-228
DE Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Frost
; Snow
; Temperature
; Periglacial
AB None
$
CL 0875
AU Thorn, C.E.
DT 1975
TI A model of nivation processes
SO Proceedings of the Association of American Geographers, 7:243-246
DE Model
; Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Snow
; Periglacial
; Water
AB None
$
CL 0884
AU Thorn, C.E.
; Darmody, R.G.
DT 1980
TI Contemporary eolian sediments in the alpine zone of the Colorado Front Range
SO Physical Geography, 1:162-171
DE Geomorphology
; Niwot Ridge
; Wind
; Sediment
; Soil
; Soil sciences
AB None
$
CL 0877
AU Thorn, C.E.
DT 1978
TI A preliminary assessment of the geomorphic role of pocket gophers in the
 alpine zone of the Colorado Front Range
SO Geografiska Annaler, 60A:181-187
DE Ecology
; Geomorphology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Mammals
; Rodents
; Soil
; Succession
AB None
$
CL 0880
AU Thorn, C.E.
DT 1979
TI Ground temperatures and surficial transport in colluvium during snowpatch
 meltout: Colorado Front Range
SO Arctic and Alpine Research, 11:41-52
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Snow
; Temperature
; Sediment
; Water
; Soil
AB None
$
CL 0883
AU Thorn, C.E. (ed.)
DT 1982
TI Space and Time in Geomorphology
SO The 'Binghamton' Symposia in Geomorphology: International Series, No. 12.
 London: George Allen and Unwin. 379 pp.
DE Overview
; Geomorphology
; Niwot Ridge
AB None
$
CL 0888
AU Thornbury, W.D.
DT 1928
TI Glaciation of the east side of the Colorado Front Range between Longs Peak
 and James Peak
SO M.A. thesis, University of Colorado.  66 pp.
DE Thesis
; Geomorphology
; Glaciology
; History
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Indian Peaks Region
; Rocky Mountain National Park - Location
; Periglacial
; Glacier
AB None
$
CL 0888a
AU Thurman, E.M.
DT 1985
TI Organic Geochemistry of Natural Waters
SO Dordrecht, Netherlands: Martinus Nijhoff/Dr W. Junk Publishers. xii + 489 pp
DE Geology
; Hydrology
; Sedimentology
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Acid Deposition
; Atmospheric Chemistry
; Sediment
; Water
; Stream
; Lake
AB None
$
CL 1206
AU Thurman, E.M.
DT 1983
TI Multidisciplinary research - an experiment
SO Environmental Science and Technology 17(11): 511A
DE NWTLTER
; Long-Term Ecological Research
; environmental chemistry
; multidisciplinary research
AB None
$
CL 0889
AU Thurman, E.M.
; Caine, N.
; Furbish, D.
DT 1984
TI Specific export of carbon in an alpine watershed
SO Bulletin of Ecological Society of America, 65(2):193. Abstract
DE Abstract
; Geomorphology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Watershed
; Water
; Carbon
AB None
$
CL 0891
AU Tieszen, L.L.
DT 1974
TI Leaf area index in the U.S. Tundra Biome
SO U.S. Tundra Biome Data Report, 74-5. 62 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Morphological
; Technique
AB None
$
CL 1242
AU Toetz, D.
; Windell, J.
DT 1993
TI Phytoplankton in a high-elevation lake, Colorado Front Range: Application to
 lake acidification
SO Great Basin Naturalist 53 (4):350-357
DE NWTLTER
; Green Lakes Valley
; phytoplankton
; diatoms
; lake acidification
; nutrients
; subalpine lake
; flagellates
; Colorado
AB The purpose of this research was to evaluate the status of phytoplankton in
 Lake Albion in the Green Lakes Valley, Colorado Front Range, with respect to
 lake acidification. The research was conducted during the inventory phase of
 the Long-Term Ecological Research program of
2000
 the University of Colorado at the
 Niwot Ridge/ Green Lakes Valley site. Lake Albion is a small subalpine lake on
 the terminal end of the Green Lakes Valley (13 ha, mean depth 6 m, and surface
 pH 6.51). Net plankton were collected six times during June-August 1984.
 Ancillary data on nutrients, temperature, chlorophyll a, and Secchi disc
 transparency were also obtained. Diatoms were identified and assigned to
 categories based upon their known tolerances to hydrogen ion concentration.
 The diatom flora was composed mostly of alkaphilic or species indifferent to
 hydrogen ion concentration, a characteristic Lake Albion shares with other
 Front Range lakes. The diatom flora and water chemistry of Lake Albion are
 compared to other high-elevation lakes.
$
CL 0893a
AU Toetz, D.
DT 1985
TI Lake productivity in the Green Lakes Valley, Front Range, Colorado - 1984
SO University of Colorado Long-Term Ecological Research Data Report 85/9. 12 pp
DE Data Report
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Algae
; Lake
; Photosynthesis
; Productivity
; Plankton
AB None
$
CL 1232
AU Toetz, D.
DT 1992
TI Use of mass spectroscopy to investigate the diet of brook trout Salvelinus
 fontinalis in an alpine lake
SO Journal of Freshwater Ecology 7: 251-256
DE NWTLTER
; mass spectroscopy
; Salvelinus fontinalis
; brook trout
; diet
; food webs
; stable isotopes
; 15N
AB Stable isotope analysis was used to investigate the food web of a Colorado
 alpine lake where cannibalism by brook trout, Salvelinus fontinalis, was
 suspected. Brook trout had higher than expected values of delta-15N compared
 to zooplankton, but not compared to insect larvae in drift into the lake or
 aerial insects. Cannibalism was not demonstrated.
$
CL 1425
AU Toetz, D.
DT 2000
TI Decomposition in an alpine wetland brook, Colorado Front Range
SO Verh. Internat. Verein. Limnol. 27: 748-751
DE Colorado; Niwot Ridge
AB Long-term ecological research (LTER) is being conducted by scientists with support from the U.S.A. National Science Foundation in select biomes in North America to produce time series data, to measure trends, to study the effects of rare events, to observe slow biogeochemical processes and to measure the vaiability of ecosystem level processes in time and space (Kratz et al. 1987). Frequently, only short-term data are available on processes such as decomposition. Furthermore, spatial variability of such processes is often unknown. The objective of this study was to determine the spatial pattern of long-term (20-year) decomposition of organic matter in an alpine brook at the Niwot Ridge/ green Lakes Valley LTER site in Colorado, USA. This paper reports weight loss and chemical composition of terrestrial plant partss after the first 4 years of decomposition.   $
CL 0893b
AU Toetz, D.
DT 1988
TI Aquatic productivity of a high elevation wetland, Colorado Front Range, an
 LTER site
SO Bulletin of Ecological Society of America, 69(2):320
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Algae
; Lake
; Productivity
; Plankton
AB None
$
CL1551
AU Toetz, D.
; Payton, M. E.
DT 2004
TI Synergism of Nutrients and Humic Acid in Accrual of Periphytic Biomass in a Subalpine Stream, Colorado Front Range
SO Journal of Freshwater Ecology vol. 19 no. 1 pp 35-40
DE NWTLTER
; DISSOLVED ORGANIC-MATTER
AB Nutrient diffusing substrata were used to test for a three-way interaction between humic acid (HA), nitrogen (N) and phosphorus (P) nutrients in North Boulder Creek, Colorado. Biomass accrual was measured after three weeks as chlorophyll a (chl a). In 2001 the experimental design was a 2x2x2 factorial arrangement of treatments in a completely randomized design. Ethylene diamine tetraacetic acid (EDTA) was also tested as a possible growth stimulant in 2002. Analysis of variance procedures were used to reveal important interactions among the three factors. Higher chl a in HA+P and N+P treatments suggested strongest synergisms between P and HA and between P and N. EDTA failed to promote as much biomass accrual as HA when N and P were supplied. It is suggested that the synergism between P and HA may simply be due to dissolved organic matter that HA provides. Alternatively, HA may provide a microhabit free of UV-B radiation which is conducive to colonization by tube-forming chironomid larvae and their algal "gardens."
$
CL 0893c
AU Toetz, D.
; Koenig, P.
; Horton, R.
DT 1986
TI Brook charr (Salvelinus fontinalus) from Green-Lake 3.  Growth, fecundity,
 metals and pesticides content
SO University of Colorado Long-Term Ecological Research Data Report 86/2. 10 pp
DE Data Report
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Fish
; Lake
; Pollution
; Mining
; Chemistry
; Growth (Development)
; Demography
; Reproduction
AB None
$
CL 1295
AU Toetz, D.
DT 1995
TI Water chemistry and periphyton in an alpine wetlan
SO Hydrobiologia 312:93-105
DE NWTLTER
; Green Lakes Valley
; alpine
; long-term ecological research
; water chemistry
; nutrient limitation
; colonization
; periphyton
AB Remote high elevation sites are thought to be good sites to monitor 
 global change and anthropogenic effects on ecosystems. This study was
 conducted during 1987-1990 in a high elevation wetland (3593m) located
 in the Green Lakes Valley, Front Range, Colorado (USA). Salix spp. was 
 the dominant riparian species in this 2 ha. wetland. Small shallow pools 
 (<0.5 m depth) constituted a water area of 236 cubic meters. The major 
 source of water during the study period was snowmelt. The wetland had a 
 well defined outlet and inlet, although an undetermined amount of water
 entered as groundwater from the snow patch above. Outlet discharge was
 424-460 cubic meters during the month of July and declined thereafter
 as water input from the snowpatch declined. Inlet discharge was 67% of
 outlet discharge. Water temperatures in the outlet were always less than 
 6.8 degrees C, pH 6.0-6.3, and mean conductivity 30.8 microS per cm.
 Both NO3- and SO42- were higher in the inlet than in the outlet. Dominant
 cations in the inlet and outlet waters were Ca2+ >> Mg2+ > K+ > Na+;
 dominant anions were SO42- >> HCO3- > NO3- >> Cl-. Nutrient limitation
 by P was demonstrated once using nutrient diffusing substrata. No limitation
 could be shown for NO3-, HCO3-, or Fe+EDTA. Slow colonization rates of
 periphyton on tiles were attributed to low temperatures and/or ultraviolet
 radiation. However, interannual differences in biomass on tiles were as 
 much as 300% after 35 days. A minimum of 16-54 samples would be needed
 to detect a significant interannual change in biomass on tiles after 35
 days assuming that the extreme case for periphyton patchiness. Global 
 climate change is likely to affect discharge and water temperature in
 this wetland which will have direct and indirect affects on population
 dynamics and ecosystem function.
$
CL 0893d
AU Toetz, D.
; McFarland, M.
DT 1987
TI Lake loading ratios (N:P) and lacustrine nitrogen fixation
SO Water Resources Bulletin 23:239-241
DE article
; ecology
; Boulder City Watershed
; algae
; lake
; watershed
; stream
; nitrogen compounds
; nutrients
; biochemical
; productivity
; NWTLTER
AB None
$
CL 0895
AU Toetz, D.
; Windell, J.T.
DT 1984
TI Observations of nitrogen fixation and nutrients in the Green Lakes, Colorado
SO New Mexico Journal of Science, 24(1):39. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Lake
; Nutrients
; Nitrogen
AB None
$
CL 0894
AU Toetz, D.W.
; Windell, J.T.
DT 1984
TI Lake productivity in the Green Lakes Valley, Front Range, Colorado - 1983
SO University of Colorado Long-Term Ecological Research Data Report, 84/5. 15
 pp.
DE Data report
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Lake
; Nitrogen
; Product
2000
ivity
; Plankton
AB None
$
CL 0893e
AU Toetz, D.W.
; Muoneke, M.
; Windell, J.T.
DT 1991
TI Age, growth, and condition of brook trout (Salvelinus phontinalis) from an
 unexploited alpine lake
SO Northwest Science, 65(3): 89-92
DE article
; ecology
; Long-Term Ecological Research Program
; Boulder City Watershed
; fish
; lake
; demography
; growth
; NWTLTER
AB None
$
CL 1490
AU Toetz, D.W.
; Mihuc, T.B.
DT 2002
TI Effects of ultraviolet radiation on algae and chironomids in a subalpine stream, Colorado Front Range
SO Verh. Internat. Verein. Limnol v. 28 pp. 1095-1100
DE NWTLTER
AB None
$
CL 1363
AU Toetz. D.W.
DT 1999
TI Multiple limiting nutrients in a subalpine stream, Colorado Front Range
SO Journal of Freshwater Ecology 14:349-355
DE NWTLTER
; nutrient limitation
; nitrogen
; phosphorus
; silicon
AB Nutrient-diffusing substrata were used to test for nutrient limitation of periphytic 
 epilithon in North Boulder Creek, Green Lakes Valley, Colorado. Both N and P were 
 co-limiting. In addition co-limitation by P and Si was observed. In a few experiments 
 humic acid promoted biomass accrual, but more research is needed to discover its exact 
 role in the growth of periphyton.
$
CL 0896
AU Tolbert, W.W.
; Tolbert, V.R.
; Ambrose, R.E.
DT 1977
TI Distribution, abundance, and biomass of Colorado alpine tundra arthropods
SO Arctic and Alpine Research, 9:221-234
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Insects
; Demography
; Distribution
; Biomass
AB None
$
CL 1523
AU Tomaszewski, T.
; Boyce, R.
; Sievering, H. 
DT 2003
TI Canopy uptake of atmospheric nitrogen and new growth nitrogen requirement at a Colorado subalpine forest
SO Can. J. of Forest Research v. 33 no. 11 pp. 2221-2227
DE NWTLTER
; SPRUCE PICEA-ABIES
; NUTRIENT RETRANSLOCATION
; THROUGHFALL CHEMISTRY
; ECOSYSTEM RESPONSES
; HIGH-ELEVATION
; NIWOT RIDGE
; FRONT RANGE
; FIR FOREST
; L KARST
; DEPOSITION
AB A field study at a Rocky Mountain spruce-fir-pine forest was undertaken to obtain canopy N uptake (CNU), N reallocation, and foliar N requirement. Wet deposition, dry deposition, and throughfall fluxes of ammonium and nitrate were measured during the 2000 and 2001 growing seasons. Estimation of CNU, for both ammonium and nitrate, was obtained by subtracting throughfall (TF) flux from the sum of wet deposition (WD) and dry deposition (DD): CNU = WD + DD - TF. CNU efficiency (CNU/(WD + DD)) for ammonium (0.9) was consistent across 2000 and 2001. For nitrate, this efficiency was 0.8 and 0.7 for 2000 and 2001, respectively. Foliar N requirement for growth in 2000 and 2001 was about 19 and 22 kg N.ha(-1).year(-1), respectively. Growing season estimates of CNU for 2000 and 2001 were approximately 2 and 3 kg N.ha(-1), respectively. Thus, CNU may contribute 10%-15% of the foliar N requirement for canopy growth. Mountain upslope winds bring substantial amounts of anthropogenic N to this forest during the growing season, thereby contributing to CNU. Given that a sizable fraction of CNU is anthropogenic in origin, the forest's N cycle has likely undergone substantial changes on a decadal time scale.
$
CL 1289
AU Tonnessen, K.A.
; Williams, M.W.
; Tranter, M.
DT 1995
TI Biogeochemistry of seasonally snow covered basins
SO International Association of Hydrological Sciences, Wallingford, UK, IAHS-AIHS
 Publication no. 228. 465 pp.
DE NWTLTER
; hydrology
; hydrochemistry
; biogeochemistry
; snow
; snow distribution
; snowpack
; snowmelt
; glacier
; runoff
; modelling
; energy flux
; deposition chemistry
; atmospheric chemistry
AB There is considerable uncertainty regarding the impacts of global change on
 natural ecosystems and human populations in regions where basin hydrology is
 dominated by the dynamics of seasonal snowpacks and glacial runoff.  We need
 to improve our understanding of both the hydrology of these regions and the
 hydrochemical changes in surface waters that might result from changes in
 patterns of snowfall, snow distribution, snow and glacier melt, and deposition
 chemistry.  Data bases on headwater basins in alpine areas worldwide have been
 developed in response to concerns about the effects of acid precipitation and
 global change on natural processes.  There is a need to expand these studies
 to include larger drainage basins to improve our ability to predict the impact
 of changes in snowpack and glacier dynamics on water users downstream.  The
 objective of this Symposium was to provide a forum for the discussion of the
 dynamics of snowpacks in glacier and seasonally snow-covered catchments and
 the development of models of physical, chemical and biological processes in
 these catchments to aid in our prediction of the impacts of global climate
 change and changes in deposition chemistry.  
$
CL 0896b
AU Trainer, M.
; Parrish, D.D.
; Fahey, D.W.
; Roberts, J.M.
; Liu, S.C.
; Albritton, D.L.
; Fehsenfeld, F.C.
DT 1985
TI Photochemical oxidants at Niwot Ridge, Colorado
SO In:  Atmospheric Ozone (C. S. Zerefos and A. Ghazi, eds.). D. Reidel, 
 Dordrecht, pp. 759-764
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
AB None
$
CL 0896a
AU Trainer, M.
; Hsie, E.Y.
; McKeen, S.A.
; Tallamraju, R.
; Parrish, D.D.
; Fehsenfeld, F.C.
; Liu, S.C.
DT 1987
TI Impact of natural hydrocarbons on hydroxyl and peroxy radicals at a remote 
 site
SO Journal of Geophysical Research 92:11879-11894
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
AB None
$
CL 0896c
AU Trainer, M.
; Williams, E.J.
; Parrish, D.D.
; Buhr, M.P.
; Allwine, E.J.
; Westberg, H.H.
; Fehsenfeld, F.C.
; Liu, S.C.
DT 1987
TI Models and observations of the impact of natural hydrocarbons on rural ozone
SO Nature 329:705-707
DE article
; NOAA - Aeronomy Lab
; Atmospheric science
; C-1 Climate Station
; atmospheric chemistry
; ozone
AB None
$
CL 1512
AU Tranter, M. 
; R. Armstrong, R.
; Brun, E.
; Jones, G.
; Sharp, M.
; Williams, M.W. 
DT 1999
TI Interactions Between the Cryosphere, Climate, and Greenhouse Gases, ed by M. Tranter, R. Armstrong, E. Brun, G. Jones, M. Sharp, and M. Williams
SO IAHS-AIHS Publication 256, International Association of Hydrological Sciences, Wallingford, UK, 281 pages
DE NWTLTER
AB None
$
CL 0898
AU Tschirley, F.H.
DT 1954
TI The altitudinal distribution of spiders in Boulder County, Colorado
SO M.A. thesis, University of Colorado, Boulder. 50 pp.
DE Thesis
; Ecology
; University of Colorado
; Niwot Ridge
; Rocky Mountain National Park - Location
; Mountain Research Station - Location
; Arachnids
; Atmospheric Chemistry
; Distribution
; Indian Peaks Region
AB None
$
CL1459
AU Turk, J.T.
; Taylor, H.E.
; Ingersoll, G.P.
; Tonnessen, K.A.
; Clow, D.W.
; Mast, M.A.
; Cambell, D.H.
; Melack, J.M.
DT 2001
TI Major-ion chemistry of the Rocky Mountain snowpack, USA
SO Atmospheric Environment 35:3957-3966
DE NWTLTER
AB None
$
CL 0907
AU U.S. Department of Interior/U.S. Department of Agriculture
DT 1979
TI Rocky Mountain National Park Boundary Study: area surrounding Rocky Mountain
 National Park, including Indian Peaks Wilderness in Arapaho and Roosevelt
 National Forests, Colorado
SO Joint Study conducted by the National Park Service and the Forest Service
DE Technical report
; Ecology
; Management
; Remote sensing
; Mountain Research Station - Affiliation
; Indian Peaks Region
; Niwot Ridge
; Plant
; Map
AB None
$
CL 0908
AU U.S. International Biological Program
DT 1972
TI Report of the US/IBP Phenology Committee, July 1972
SO Environmental Programs Coordinating Office, U.S. Component of the
 International Biological Program. 54 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Plant
; Animals
; Phenological (seasonal)
AB None
$
CL 0909d
AU Veblen, T.T.
; Hadley, K.S.
; Reid, M.S.
; Robertus, A.J.
DT 1991
TI Methods of detecting past spruce beetle outbreaks in Rock
2000
y Mountain
 subalpine forests.
SO Canadian Journal of Forest Research 21(2):242-
DE article
; technique
; ecology
; University of Colorado
; Niwot Ridge
; insects
; anthropogenic
; disturbance
; recovery
; conifers
; tree
AB None
$
CL 0909e
AU Veblen, T.T.
; Hadley, K.S.
; Reid, M.S.
; Robertus, A.J.
DT 1991
TI The response of subalpine forests to spruce beetle outbreak in Colorado
SO Ecology 72:213-231
DE article
; ecology
; University of Colorado
; Niwot Ridge
; anthropogenic
; disturbance
; recovery
; conifers
; tree
AB None
$
CL 0909f
AU Veblen, T.T.
; Lorenz, D.C.
DT 1986
TI Anthropogenic disturbance and recovery patterns in montane forests, Colorado
 Front Range
SO Physical Geography 7:1-24
DE article
; ecology
; University of Colorado
; Niwot Ridge
; anthropogenic
; disturbance
; recovery
; conifers
; tree
AB None
$
CL 0909a
AU Veblen, T.T.
DT 1986
TI Age and size structure of subalpine forests in the Colorado Front Range
SO Bulletin of the Torrey Botanical Club, 113:225-240
DE article
; ecology
; University of Colorado
; Boulder City Watershed
; Indian Peaks Region
; conifers
; demography
; tree
AB None
$
CL 0909g
AU Veblen, T.T.
; Lorenz, D.C.
DT 1991
TI The Colorado Front Range: A century of ecological change
SO University of Utah Press, Salt Lake City
DE overview
; ecology
; University of Colorado
; Niwot Ridge
; anthropogenic
; disturbance
; recovery
; conifers
; tree
AB None
$
CL 0911
AU Vetter-Sauchyn, M.A.
DT 1981
TI The physiological ecology of Sedum lanceolatum in the Colorado Front Range
SO Ph.D. Dissertation, Duke University. 235 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Physiological
; Bioenergetics
; Reproduction
AB None
$
CL 0911A
AU Wahle, B.M.
DT 1988
TI Benthos data from the Green Lakes Valley flowage system
SO University of Colorado Long-Term Ecological Research Working Paper 88/4. 51
 pp
DE Data Report
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Plants
; Algae
; Lake
; Productivity
; Taxonomy
AB None
$
CL 0912
AU Wahlstrom, E.
DT 1933
TI Geology of the Lake Albion region, Boulder County, Colorado
SO M.A. thesis, University of Colorado, Boulder. 47 pp.
DE Thesis
; Geology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Lake
AB None
$
CL 0913
AU Wahlstrom, E.E.
DT 1940
TI Audubon-Albion stock, Boulder County, Colorado
SO Geological Society of America Bulletin, 51:1789-1820
DE Geology
; University of Colorado
; Niwot Ridge
; Chemistry
AB None
$
CL 0917
AU Waldrop, H.A.
DT 1964
TI Arapaho Glacier: a sixty-year record
SO University of Colorado Studies, Series in Geology No. 3. 37 pp. Abstract
 reprinted in:Ives, J.D. (ed.), 1980: Geoecology of the Colorado Front Range.
 Boulder: Westview Press, 202. Abstract
DE Abstract
; Glaciology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0918
AU Waldrop, H.A.
; White, S.E.
DT 1965
TI Arapaho Glacier and Arapaho Rock Glacier
SO In: Schultz, C.B. and Smith, H.T.U. (eds.), Guidebook for One-Day Field
 Conferences, Boulder Area, Colorado. International Association for Quaternary
 Research, VII Congress, 5-10
DE Geomorphology
; Glaciology
; Boulder Watershed and Rainbow Lakes
; Periglacial
; Glacier
AB None
$
CL 0916
AU Waldrop, H.A.
DT 1962
TI Arapaho Glacier, Boulder County, Colorado
SO M.S. thesis, University of Colorado. 91 pp.
DE Thesis
; Glaciology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 1239
AU Walker, D.A.
; Halfpenny, J.C.
; Walker, M.D.
; Wessman, C.A.
DT 1993
TI Long-term studies of snow-vegetation interactions
SO BioScience 43: 287-301
DE NWTLTER
; GIS
; Niwot Ridge Saddle
; Green Lakes Valley
; climatology
; global change
AB None
$
CL 1442
AU Walker, D.A.
; Molenaar, J.G.
; Billings, W.D.
DT 2001
TI Snow-vegetation interactions in tundra environments
SO Chapter 6 In: Jones, H.G., J. Pomeroy, D.A. walker, and R. Wharton (eds.). Snow Ecology: An interdisciplinary examination of snow-covered ecosystems. Cambridge University Press.
DE None
AB None
$
CL 1218
AU Walker, D.A.
; Walker, M.D.
DT 1991
TI History and pattern of disturbance in Alaskan arctic terrestrial ecosystems:
 A hierarchical approach to analysing landscape change
SO Journal of Applied Ecology 28: 244-276
DE NWTLTER
; scale
; GIS
; disturbance
; Arctic
AB None
$
CL 1244
AU Walker, D.A.
; Lewis, B.E.
; Krantz, W.B.
; Price, E.T.
; Tabler, R.D.
DT 1994
TI Hierarchic studies of snow-ecosystem interactions: A 100-year 
 snow-alteration experiment 
SO Pp 407-414 In: Ferrik, M. (ed.), Proceedings of the Fiftieth Annual 
 Eastern and Western Snow Conference, Quebec City, Quebec, Canada, 
 8-10 June 1993
DE NWTLTER
; Niwot Ridge
; Saddle
; snow
; vegetation
; NDVI
; soil temperature
AB The Niwot Long-Term Ecological Research (LTER) project is examining the
 long-term ecological effects of altered snowpack regimes. Key components
 of the studies include: (1) hierarchic analysis of the relationship 
 between natural snowpack patterns and geobotanical features, and (2) a
 snow-fence experiment. A 3-m high snow fence will be built in the summer
 of 1993. Baseline soil-temperature and snow-depth studies were initiated
 during the unusually wet winter of 1992-93 (183% of normal precipitation
 at the D-1 climate station on Niwot Ridge). Minimum winter soil 
 temperatures (15-cm depth) were about -10 degrees Celsius.
$
CL 0918a
AU Walker, M.D.
; Herger, L.
; Webber, P.J.
; Benjamin, T.
DT 1988
TI Below-ground live vascular phytomass data, 1987, Martinelli Slope site
SO University of Colorado Long-Term Ecological Research Data Report 88/2. 11 pp
DE Data Report
; Technique
; Martinelli
; Long-Term Ecological Research Program
; Ecology
; Plants
; Soils
; Productivity
AB None
$
CL 1377
AU Walker, M.D.
; Walker, D.A.
; Welker, J.M.
; Arft, A.M.
; Bardsley, T.
; Brooks, P.D.
; Fahnestock, J.T.
; Jones, M.H.
; Losleben, M.
; Parsons, A.N.
; Seastedt, T.R.
; Turner, P.L.
DT 1999
TI Long-term experimental manipulation of winter snow regime and summer 
 temperature in arctic and alpine tundra
SO Hydrological Processes 13:2315-2330
DE NWTLTER
; arctic tundra
; alpine tundra
AB Three 60 m long, 2.8 m high snowfences have been erected to study 
 long-term effects of changing winter snow conditions on arctic and 
 alpine tundra.  This paper describes the experimental design and 
 short-term effects.  Open-top fiberglass warming chambers are placed 
 along the experimental snow gradients and in controls areas outside 
 the fences; each warming plot is paired with an unwarmed plot.  
 The purpose of the experiment is to examine short- and long-term 
 changes to the integrated physical-biological systems under simultaneous 
 changes of winter snow regime and summer temperature, as part of the 
 Long-Term Ecological research network and the International Tundra Experiment.  
 The sites were at Niwot ridge, colorado, a temperate high altitude site in 
 the Colorado Rockies, and Toolik Lake, Alaska high-latitude site.  
 Initial results indicate that although experimental designs are 
 essentially identical at the arctic and alpine sites, experimental 
 effects are different.  The drift of Niwot Ridge lasts much longer 
 than do the Toolik Lake drifts o that the Niwot Ridge fence affects 
 both summer and winter conditions, whereas the Toolik Lake fence 
 affects primarily winter conditions.
 The temperature experiment also differs in effect between sites.  
 Although the average temperature increase at the two sites is similar 
 (daily increase 1.5 degrees C at Toolik and 1.9 degrees C at Niwot Ridge),
 at Toolik Lake there is only minor diurnal variation, whereas at Niwot 
 Ridge the daytime increases are extreme on sunny days (as much a 7-10 
 degrees C), and minimum nighttime temperatures in the chambers are often 
 slightly co
2000
oler than ambient (by about 1 degree C)temperatures in the 
 chambers are often slightly cooler than ambient (by about 1 degree C).  
 The experimental drifts resulted in wintertime increases in temperature 
 and Co2 flux.  Temperatures under the deep drifts were much more consistent 
 and warmer than in control areas, and at Niwot Ridge remained very close 
 to 0 degrees C all winter.  These increased temperatures were likely 
 responsible for observed increases in system carbon loss.  Initial changes 
 to the above ground biotic system included an increase in growth in response 
 to both snow and warming, despite  a reduced growing season .  This is 
 expected to be a transient response that will eventually be replaced by 
 reduced growth.  At least one species, Kobresia myosuroides, had almost 
 completely died at Niwot Ridge three years after fence construction, 
 whereas other species were increasing.  We expect in both the short- 
 and long-term to see the strongest effects of snow at the Niwot Ridge 
 site, and stronger effects of temperature at Toolik Lake.
$
CL 1275
AU Walker, M.D.
; Ingersoll, R.C.
; Webber, P.J.
DT 1995
TI Effects of interannual climate variation on phenology and growth 
 of two alpine forbs
SO Ecology 76:1067-1083
DE NWTLTER
; Niwot Ridge Saddle
; Acomastylis rossii
; alpine vegetation
; Bistorta bistortoides
; climate
; Colorado Rockies
; growth
; long-term ecological research
; phenology
; snow
AB Variations in growth, flowering, and phenology of two forbs, Acomastylis
 rossii and Bistorta bistortoides, were compared among six years (1983-1988)
 and five plant communities (fellfield, dry meadow, moist meadow, wet 
 meadow, snowbed) at an alpine site in the Front Range of Colorado. The
 purpose was to determine the extent to which the phenological patterns of
 these species varied among plant communities and how interannual climate
 variability affects phenology and growth. There were significant differences
 in growth among communities for both species. In B. bistortoides, there were
 also significant differences among years, due primarily to the influence of
 a single year (1983) when leaf length increased by ~10% and the average
 number of B. bistortoides leaves nearly doubled. Key phenological events of
 both species (initiation of growth, date of maximum leaf length, leaf 
 number, and flower number) were related to snowmelt patterns, resulting in
 differences among communities. There were also significant differences 
 among years, again primarily related to the single year 1983, the year of
 a major El Nino Southern Oscillation (ENSO) event that produced high 
 snowfall amounts at the site. The increased leaf length in a high snow
 year is counterintuitive to the commonly accepted notion that alpine 
 species may be limited by season length. We hypothesize that changes in 
 phenology related to changes in snowfall or snowmelt will cause 
 detectable changes in growth, but that these will not be predicted simply
 from phenology alone. Rather, the timing of snowmelt in relation to 
 nutrient availability, soil moisture, and air temperature will be critical
 in determining how individual species respond.
$
CL 1247
AU Walker, M.D.
; Webber, P.J.
; Arnold, E.H.
; Ebert-May, D.
DT 1994
TI Effects of interannual climate variation on aboveground phytomass in alpine
 vegetation
SO Ecology 75:393-408
DE NWTLTER
; alpine tundra
; climate change
; Colorado
; ecosystems
; path analysis
; phytomass
; plant community
; soil moisture
; Niwot Ridge Saddle
AB Relationships between peak annual vascular aboveground phytomass and annual
 climate variation in alpine plant communities located on Niwot Ridge,
 Colorado, were analyzed using path analysis. The five community types,
 fellfield, dry meadow, moist meadow, wet meadow, and snowbed, represent a snow
 depth-soil moisture gradient and broadly represent the most common vegetation
 types on east-facing slopes of of the Front Range alpine zone. Using nine
 successive years of data, this is the first longer term analysis of alpine
 phytomass and climate and one of the longest nonagricultural production
 records available. Live phytomass ranged from 97 g/m^2 (snowbed) to 237 g/m^2
 (fellfield). Among-community differences in phytomass were greater than
 differences among years, but there was also significant phytomass variation
 among years. Path analysis indicated that climate accounted for 15-40% of the
 variation in phytomass. The dry communities, fellfield (exposed rocky summit
 areas dominated by cushion and mat plants) and dry meadow, were most sensitive
 to previous year precipitation, the moist and wet meadow communities were most
 sensitive to current growing season soil moisture, and the snowbed community
 was most sensitive to date of snow release. Because of the relatively high
 amount of variation attributable to variables related to precipitation,
 changes in precipitation regimes that may occur in alpine ecosystems will
 likely result in changes in phytomass that are detectable with clip-harvest
 methods.
$
CL 1434
AU Walker, M.D.
; Walker, D.A.
; Theodose, T.A.
; Webber, P.J.
DT 2001
TI The vegetation: hierarchical species-environment relationships
SO Chapter 6 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL 0919
AU Wallace, R.G.
DT 1967
TI Types and rates of alpine mass movement, west edge of Boulder County,
 Colorado, Front Range
SO Ph.D. dissertation, Ohio State University, Columbus. 200 pp.
DE Dissertation
; Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Altitude
; Sediment
; Periglacial
; Water
; Avalanche
AB None
$
CL 0919a
AU Warburton, J.
DT 1985
TI Raleigh convection and the initiation of sorted patterned ground: three
 field investigations
SO M.A. thesis, University of Colorado, Boulder, 127 pp.
DE thesis
; geomorphology
; Long-Term Ecological Research Program
; Boulder City Watershed
; permafrost
; periglacial
; soil
AB None
$
CL 0922
AU Wardle, P.
DT 1974
TI Alpine timberline.
SO In: Ives, J.D. and Barry, R.G., (eds.) Arctic and Alpine Environments.
 London: Methuen, 371-402
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Physiological
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0921
AU Wardle, P.
DT 1968
TI Engelmann spruce (Picea engelmannii Engel.) at its upper limits on the Front
 Range, Colorado
SO Ecology, 49:483-495. Reprinted in: Ives, J.D., (ed.), 1980: Geoecology of
 the Colorado Front Range. Boulder: Westview Press, 339-350
DE Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Physiological
; Tree
; Forest-Tundra Ecotone (Timberline)
AB None
$
CL 0923
AU Washichek, J.N.
DT 1972
TI Summary of Snow Survey Measurements for Colorado and New Mexico
SO Denver: Soil Conservation Service. 208 pp.
DE Technical report
; Hydrology
; Boulder Watershed and Rainbow Lakes
; Snow
AB None
$
CL 0924
AU Waterman, S.
DT 1979
TI Investigation of multispectral remote sensing on snow cover using solar
 radiation model
SO Ph.D. dissertation, University of Colorado, Boulder. 206 pp.
DE Dissertation
; Model
; Hydrology
; Remote sensing
; NASA - PY
; Niwot Ridge
; Insolation
; Snow
; Water
AB None
$
CL 0937
AU Webber, P.J.
; Halfpenny, J.C.
DT 1984
TI Niwot Ridge/Green Lakes Long-Term Ecological Research
SO New Mexico Journal of Science, 24(1):48. Abstract
DE Abstract
; Overview
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
AB None
$
CL 0935
AU Webber, P.J.
; Emerick, D.C.
; Ebert-May, D.C.
; Komarkova, V.
DT 1976
TI The impact of increased snowfall on alpine vegetation
SO In: Steinhoff, H.W. and Ives, J.D. (eds.), Ecological Impacts of Snowpack
 Augmentation in the San Juan Mountains, Colorado. Final Report, San Juan
 Ec
2000
ology Project prepared for U.S. Department of Interior, Bureau of
 Reclamation. Fort Collins, Colorado State University. CSU-FNR-7052-1, 201-264
DE Technical report
; Ecology
; Management
; San Juan Ecology Project
; Niwot Ridge
; Angiosperms
; Snow
; Demography
; Morphological
AB None
$
CL 0942
AU Webber, P.J.
; Pollak, O.D.
; Lederer, N.D.
DT 1984
TI The significance of long-term measurement of primary production in six
 Colorado alpine communities
SO Bulletin of Ecological Society of America, 65(2):248. Abstract
DE Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Community
; Productivity
AB None
$
CL 0938
AU Webber, P.J.
; Keigley, R.B.
DT 1982
TI Defining disturbance and stability in northern ecosystems
SO Proceedings of the 33rd Alaskan Science Conference, 208. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; Disturbances
AB None
$
CL 0927
AU Webber, P.J.
DT 1977
TI Belowground tundra research: A commentary
SO Arctic and Alpine Research, 9:105-111
DE Overview
; Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Soil
; Productivity
; Biomass
AB None
$
CL 0940
AU Webber, P.J.
; May, D.E.
DT 1977
TI The magnitude and distribution of below ground plant structures in the
 alpine tundra of Niwot Ridge, Colorado
SO Arctic and Alpine Research, 9:157-174. Reprinted in: Ives, J.D. (ed)., 1980:
 Geoecology of the Colorado Front Range. Boulder: Westview Press, 412-429
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Soil
; Distribution
; Biomass
AB None
$
CL 0931
AU Webber, P.J.
; Andrews, J.T.
DT 1973
TI Lichenometry: A commentary
SO Arctic and Alpine Research, 5:295-302
DE Technique
; Ecology
; Geomorphology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Lichens
AB None
$
CL 0936
AU Webber, P.J.
; Halfpenny, J.C.
DT 1982
TI Niwot Ridge/Green Lakes LTER Research Site (Front Range, Colorado, U.S.A.)
SO Bulletin of the Ecological Society of America, 63(2):117. Abstract
DE Abstract
; Overview
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
AB None
$
CL 0934
AU Webber, P.J.
; Ebert, D.C.
DT 1973
TI Ordination and production of tundra vegetation from Niwot Ridge, Colorado,
 and Point Barrow, Alaska
SO U.S. Tundra Biome Data Report, 73-22. 72 pp.
DE Technical report
; Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Snow
; Soil
; Climate - Discussion of
; Productivity
; Phytosociology
AB None
$
CL 0933
AU Webber, P.J.
; Caine, T.N.
; Andrews, J.T.
; Keigley, R.
DT 1984
TI Temporal variability in Long-Term Ecological Research
SO New Mexico Journal of Science, 24(1):44. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Climate - Discussion of
; Plant
AB None
$
CL 0929
AU Webber, P.J.
DT 1981
TI Niwot Ridge, Colorado, U.S.A.
SO In: Bliss, L.C., Heal, O.W., and Moore, J.J. (eds.), Tundra Ecosystems: A
 Comparative Analysis. Cambridge: Cambridge University Press, 780-782
DE Geoecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Plant
; Animals
; Climate - Discussion of
AB None
$
CL 0925
AU Webber, P.J.
DT 1972
TI Comparative ordination and productivity of tundra vegetation
SO In: Bowen, S. (ed.), Proceedings 1972 Tundra Biome Symposium, Lake
 Wilderness Center, University of Washington, 3-5 April 1972. U.S. IBP Tundra 
 Biome, 55-60
DE Ecology
; U.S. International Biological Programme
; Niwot Ridge
; Angiosperms
; Soil
; Climate - Discussion of
; Productivity
; Phytosociology
AB None
$
CL 0926
AU Webber, P.J.
DT 1974
TI Tundra primary productivity
SO In: Ives, J.D. and Barry, R.G. (eds.), Arctic and Alpine Environments.
 London: Methuen, 445-473
DE Ecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Angiosperms
; Climate - Discussion of
; Productivity
; Overview
AB None
$
CL 0932
AU Webber, P.J.
; Caine, N.
; Andrews, J.T.
; Keigley, R.
DT 1982
TI Temporal variability in Long-Term Ecological Research (LTER): some examples
 from the Colorado alpine environment
SO Bulletin of the Ecological Society of America, 63(2):119. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Climate - Discussion of
; Plant
AB None
$
CL 0941
AU Webber, P.J.
; Pollak, O.D.
; Lederer, N.D.
DT 1984
TI Peak season standing crop and annual production data for six alpine plant
 communities from the Saddle, Niwot Ridge  1982 and 1983
SO University of Colorado Long-Term Ecological Research Data Report, 84/4. 21
 pp.
DE Data report
; Ecology
; Long-Term Ecological Research Program
; Saddle, Niwot Ridge
; Angiosperms
; Community
; Productivity
; Biomass
AB None
$
CL 0928
AU Webber, P.J. (ed.)
DT 1979
TI High Altitude geoecology. AAAS Selected Symposium No. 12.
SO Boulder: Westview Press. 188 pp.
DE Overview
; Geoecology
; Institute of Arctic and Alpine Research
; Niwot Ridge
; Plant
; Animals
AB None
$
CL 0942a
AU Weber, U.
DT 1988
TI Dendrooekologische studie in Douglasien- und Blaufichtenbestanden, Front
 Range, Colorado
SO Diplomarbeit thesis, University of Basel, Basel, 138 pp.
DE thesis
; paleoecology
; Mountain Research Station Program
; Indian Peaks Region
; conifers
; climate - discussion of
; tree
AB None
$
CL 0949
AU Weber, W.A.
DT 1966
TI Additions to the flora of Colorado. IV
SO University of Colorado Studies, Series in Biology, 23:1-24
DE Flora
; Taxonomy & systematics
; University of Colorado
; Niwot Ridge
; Angiosperms
; Distribution
AB None
$
CL 0952
AU Weber, W.A.
; Shushan, S.
DT 1955
TI The lichen flora of Colorado: Centraria, Cornicularia, Dactylina, and
 Thamnolia
SO University of Colorado Studies, Series in Biology, 3:115-134
DE Flora
; Taxonomy & systematics
; University of Colorado
; Niwot Ridge
; Lichens
AB None
$
CL 0946
AU Weber, W.A.
DT 1961
TI Additions to the Flora of Colorado
SO University of Colorado Studies, Series in Biology, 7:1-26
DE Taxonomy and systematics
; University of Colorado
; Tracheophytes
; Distribution
AB None
$
CL 0945
AU Weber, W.A.
DT 1955
TI Additions to the Flora of Colorado - II
SO University of Colorado Studies, Series in Biology, 3:65-109
DE Taxonomy and systematics
; University of Colorado
; Spermopsida
; Distribution
AB None
$
CL 0943
AU Weber, W.A.
DT 1949
TI The Flora of Boulder County, Colorado
SO Department of Biology and the University of Colorado Museum, Boulder
DE Flora
; Taxonomy & systematics
; University of Colorado
; Plant
AB None
$
CL 0950
AU Weber, W.A.
DT 1973
TI Guide to the mosses of Colorado
SO University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper, 6. 48 pp.
DE Flora
; Taxonomy & systematics
; University of Colorado
; Indian Peaks Region
; Bryophytes
AB None
$
CL 0947
AU Weber, W.A.
DT 1961
TI Studies of Colorado Bryophytes
SO University of Colorado Studies, Series in Biology, 7:27-52
DE Taxonomy and systematics
; University of Colorado
; Spermopsida
; Distribution
AB None
$
CL 0951
AU Weber, W.A.
DT 1976
TI Rocky Mountain Flora, 5th edition
SO Boulder: Colorado Associated University Press. viii + 438 pp.
DE Flora
; Taxonomy & systematics
; University of Colorado
; Indian Peaks Region
; Tracheophytes
AB None
$
CL 0944
AU Weber, W.A.
DT 1953, 1961
TI Handbook of Plants of the Colorado Front Range
SO Boulder: University of Colorado Press. (Revised editions under the title
 Rocky Mountain Flora.) 232 pp.
DE Flora
; Taxonomy & systematics
; University of Colorado
; Plant
AB None
$
CL 1332
AU Welker, J.M.
; Molau, U.
; Parsons, A.N.
; Robinson, C.
; Wookey, P.A.
DT 1997
TI Responses of Dryas Octopetala to ITEX environmental manipulations:
 a synthesis with circumpolar comparisons.
SO Global Change Biology 3: 61-73
DE NWTLTER
; tundra
; climate change
; dwarf shrub
; Arctic
; alpine
; comparative studies
; ITEX
AB We have exam
2000
ined organismic responses of Dryas octopetala to simulated
 changes in the summer climate at four tundra sites as part of the International
 Tundra Experiment (ITEX). Our study sites are located in the High Arctic, on
 Svalbard, Norway, in the Low Arctic at Abisko, Sweden, and at Toolik Lake,
 Alaska, USA and our temperate alpine site is at Niwot Ridge, Colorado, USA.
 These sites represent a range of tundra temperature and precipitation regimes,
 being generally cold and dry in the High Arctic and warmer and wetter at 
 Toolik Lake and Niwot Ridge. Results from our studies indicate organismic
 attributes such as flowering shoot length varies by 30% between low and high
 arctic populations and that experimental warming results in significant
 increases in shoot height at three of four sites. We find that phenological
 development of Dryas is accelerated under experimentally warmed conditions
 which corresponds with a lengthening of the growing season in autumn, greater
 degrees of seed set and a higher likelihood of colonization of bare ground.
 We also observe that Dryas dominated ecosystems which are exposed to 
 experimental manipulations are capable of exhibiting net carbon sequestration
 in late autumn, and that Dryas photosynthesis and green leaf biomass is 
 significantly greater under warmer as opposed to ambient temperature 
 conditions. Dryas leaf nitrogen is also significantly lowered under warmer
 conditions resulting in senescent leaves having a higher C:N ratio than those
 under ambient conditions. Together these findings indicate that Dryas phenology
 and carbon flux may be altered to the greatest degree in spring and again in
 autumn by higher summer temperatures and that simultaneously both positive
 and negative feedback effects may result from changes in plant and ecosystem
 performance.
$
CL 1364
AU Welker, J.M.
; Brown, K.A.
; Fahnestock, J.T.
DT 1999
TI CO2 flux in arctic and alpine dry tundra: comparative field responses under ambient
 and experimentally warmed conditions
SO Arctic, Antarctic, and Alpine Research 31:308-313
DE NWTLTER
; carbon dioxide
; alpine tundra
; arctic tundra
AB We compared growing season CO2 flux patterns between botanically similar arctic and 
 alpine dry tundra ecosystems in Alaska and Colorado under ambient and experimentally warmed 
 conditionsconditions.  Measurements weree taken during the 1997 growing season, 3 yr 
 after the warming treatments were begun.  Under ambient weather conditions, arctic dry 
 tundra at Toolik Lake, Alaska was a net source (4 g CO2-C m-2) of CO2 to the atmosphere, 
 while alpine dry tundra at Niwot Ridge, Colorado, was a net CO2 sink (7 g CO2-C m-2) 
 during the growing season.  Experimental warming of arctic tundra by 1 to 3 degree C, 
 resulted in a sevenfold (32 g CO2-C m-2) increase in this ecosystem's carbon source activity.  
 Similar warming in alpine tundra changed this ecosystem from a net carbon sink to a net 
 carbon source of 8 g CO2-C m-2 over the growing season.  In the arctic, increased CO2 
 efflux with warming was largely the result of increased rates of ecosystem respiration 
 throughout the entire growing season, while in the alpine ecosystem respiration increased 
 only early in the growing season.  Rates of photosynthesis were generally not affected 
 by experimental warming at either site.  These data suggest that global warming will 
 accentuate the carbon source activity of dry dundra in the northern foothills of Alaska 
 and will change the net CO2 exchange of alpine dry tundra in the northern Rocky Mountains 
 from a net CO2 sink to a source. 
$
CL 1440
AU Welker, J.M.
; Bowman, W.D.
; Seastedt, T.R.
DT 2001
TI Environmental change and future directions in alpine research
SO Chapter 16 In: Bowman, W.D. and T.R. Seastedt. (eds.) Structure and function of an alpine ecosystem. Oxford University Press
DE None
AB None
$
CL1466
AU West, A.E.
; Schmidt, S.K.
DT 2002
TI Endogenous methanogenesis stimulates oxidation of atmospheric CH4 in alpine tundra soil
SO Microbial Ecology 43:408-415
DE NWTLTER
AB None
$
CL 1340
AU West, A.E.
; Schmidt, S.K.
DT 1998
TI Wetting stimulates atmospheric CH4 oxidation by alpine soil
SO FEMS Microbiology Ecology 25:349-353
DE NWTLTER
; methane
; soil CH4
; oxidation
; dry-rewet
; methanotroph
; alpine tundra soil
AB Studies were done to assess the effects of soil moisture manipulations on CH4 oxidation
 in soils from a dry alpine tundra site. When water was added to these soils there was a
 stimulation of CH4 oxidation. This stimulation of CH4 oxidation took time to develop. One 
 to three days after water additions no stimulation was observed. Nine days after rewetting, 
 CH4 oxidation was greatly stimulated. This time delay suggests that methanotrophs grew in 
 response to water additions, or that they take a long time to recover from metabolically 
 inactive resting stages.
$
CL 1401  
AU West, A.E.
DT 1998
TI Microbial ecology of methane metabolism in alpine tundra soils
SO PhD dissertation, University of Colorado, Boulder. 170 pp.
DE None
AB None 
$
CL 1423   
AU West, A.E.
; Schmidt, S.K.
DT 1999
TI Acetate stimulates atmospheric CH4 oxidation by an alpine tundra soil 
SO Soil Biology and Biochemistry
DE None
AB None
$
CL 1352
AU West, A.E.
; Brooks, P.D.
; Fisk, M.C.
; Smith, L.K.
; Holland, C.H.
; Jaeger, C.H.
; Babcock, S.
; Lai, R.S.
; Schmidt, S.K.
DT 1999
TI Landscape patterns of CH4 fluxes in an alpine tundra ecosystem
SO Biogeochemistry 45:243-264
DE NWTLTER
; alpine tundra
; methane
; trace gas
AB We measured CH4 fluxes from three major plant communities characteristic of alpine 
 tundra in the Colorado Front Range. Plant communities in this ecosystem are determined 
 by soil moisture regimes induced by winter snowpack distribution. Spatial patterns
 of CH4 flux during the snow-free season correspond roughly with these plant communities.
 In Carex-dominated meadows, which receive the most moisture from snowmelt, net CH4
 production occurred. However, CH4 production in one Carex site (seasonal mean = +8.45
 mg CH4 per square meter per day) was significantly larger than in the other Carex sites 
 (seasonal means = -0.06 and +0.05 mg CH4 per square meter per day). This high CH4 flux
 may have resulted from shallower snowpack during the winter. In Acomastylis meadows, which
 have an intermediate moisture regime, CH4 oxidation dominated (seasonal mean = -0.43
 mg CH4 per square meter per day). In the windswept Kobreasia meadow plant community, which
 receive the least amount of moisture from snowmelt, only CH4 oxidation was observed
 (seasonal mean = -0.77 mg CH4 per square meter per day). Methane fluxes correlated
 with a different set of environmental factors within each plant community. In the Carex
 plant community, CH4 emission was limited by soil temperature. In the Acomastylis meadows,
 CH4 oxidation rates correlated positively with soil temperature and negatively with soil
 moisture. In the Kobresia community, CH4 oxidation was stimulated by precipitation. Thus,
 both snow-free season CH4 fluxes and the controls on those CH4 fluxes were related to the
 plant communities determined by winter snowpack.
$
CL 0954
AU Western Resource Development Corporation, 1984: Mule Deer Study: Current
 Conditions and Management
SO Report prepared for City of Boulder, Colorado. 46 pp.
DE Technical report
; Ecology
; Indian Peaks Region
; Artiodactyls
; Movement
; Mountain Research Station - Location
AB None
$
CL 0960
AU White, S.E.
DT 1976
TI Rock glaciers and block fields: Review and new data
SO Quarternary Research, 6:77-97
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0959
AU White, S.E.
DT 1974
TI Comment: Relative age dating technique and a late Quaternary chronology,
 Arikaree Cirque, Colorado
SO Geology, 2:326. Reprinted in: Ives, J.D. (ed.), 1980: Geoecology of the
 Colorado Front Range. Boulder: Westview Press, 56
DE Geomorphology
; Chronology
; M
2000
ountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Lichens
; Snow
; Periglacial
AB None
$
CL 0955
AU White, S.E.
DT 1967
TI Rockfall, alluvial, and avalanche talus in the Colorado Front Range.
 Abstracts for 1967
SO Geological Society of America Special Publication 115:237. Abstract
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Altitude
; Sediment
; Avalanche
AB None
$
CL 0958
AU White, S.E.
DT 1972
TI Alpine subnival boulder pavements in Colorado Front Range
SO Geological Society of America Bulletin, 83:195-200
DE Geomorphology
; Indian Peaks Region
; Periglacial
AB None
$
CL 0956
AU White, S.E.
DT 1971
TI Debris falls at the front of Arapaho rock glacier, Colorado Front Range,
 U.S.A.
SO Geografiska Annaler 53A(2):86-91
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Altitude
; Sediment
; Periglacial
; Avalanche
AB None
$
CL 0962
AU White, S.E.
DT 1981
TI Alpine mass movement forms (noncatastrophic): classification, description,
 and significance
SO Arctic and Alpine Research, 13:127-137
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Niwot Ridge
; Wind
; Sediment
; Water
AB None
$
CL 0963
AU White, S.E.
DT 1982
TI Physical and geological nature of the Indian Peaks, Colorado Front Range
SO In: Halfpenny, J.C. (ed.), Ecological studies in the Colorado Alpine.
 University of Colorado, Institute of Arctic and Alpine Research, Occasional
 Paper, 37:1-12
DE Overview
; Geology
; Geomorphology
; Long-Term Ecological Research Program
; Mountain Research Station - Affiliation
; Indian Peaks Region
; NWTLTER
AB None
$
CL 0961
AU White, S.E.
DT 1971
TI Rock glacier studies in the Colorado Front Range, 1961 - 1968
SO Arctic and Alpine Research, 3:43-64. Reprinted in part in: Ives, J.D. (ed.),
 1980: Geoecology of the Colorado Front Range. Boulder: Westview  Press,
 102-122
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Glacier
AB None
$
CL 0957
AU White, S.E.
DT 1971
TI Rock glacier studies in the Colorado Front Range, 1961 to 1968
SO Arctic and Alpine Research, 3:43-64
DE Geomorphology
; Mountain Research Station - Affiliation
; Boulder Watershed and Rainbow Lakes
; Periglacial
; Glacier
AB None
$
CL 0964
AU Whitworth, M.R.
; Southwick, C.H.
DT 1984
TI Sex differences in the ontogeny of social behavior in pikas; possible
 relationships to dispersal and territoriality
SO Behavioral Ecology and Sociobiology, 15:175-182
DE Behavior
; University of Colorado
; Mount Evans and Guanella Pass Region
; Lagomorphs
; NWTLTER
AB None
$
CL 1354
AU Wickland, K.P
; Striegl, R.G.
; Schmidt, S.K.
; Mast, M.A.
DT 1999
TI Methane flux in subalpine wetland and unsaturated soils in the southern Rocky Mountains
SO Global Biogeochemical Cycles 13:101-113
DE NWTLTER
; methane
; soil
AB Methane exchange between the atmosphere and subalpine wetland and unsaturated soils was 
 evaluated over a 15-month period during 1995-1996.  Four vegetation community types along 
 a moisture gradient (wetland , moist-grassy, moist-mossy, and dry) were included in a 100 m 
 sampling transect situated at 3200 m elevation in Rocky Mountain National Park, Colorado.  
 Methane fluxes and soil temperature were measured during snow-free and snow-covered periods, 
 and soil moisture content was measured during snow-free periods.  The range of mean measured 
 fluxes through all seasons ( a positive value represents CH4 efflux to the atmosphere) were: 
 0.3 to 29.2 mmol CH4 m-2d-1 wetland area; 0.1 to 1.8 mmol CH4 m-2 d-1 moist-grassy area; -0.04 
 to 0.7 mmol CH4 m-2 d-1 moist-mossy area; amd -0.6 to 0 mmol CH4 m-2 d-1, dry area.  Methane 
 efflux was significantly correlated with soil temperature (5 cm) at the continuously saturated 
 wetland area during snow-free periods. Consumption of atmospheric methane was significantly 
 correlated with moisture content in the upper 5 cm of soil at the dry area. A model based on 
 the wetland flux-temperature relationship estimated an annual methane emission of 2.53 mol 
 CH4 m-2 from the wetland.  Estimates of annual methane flux based on field measurements at 
 the other sites were 0.12 mol CH4 m-2 st-grassy area; 0.03 mol CH4 m-2, moist-mossy area; 
 and -0.04 mol CH4 m-2  rea. Methane fluxes during snow-covered periods were responsible for 
 25, 73, 23, and 43% of the annual fluxes at the wetland, moist-grassy, moist-mossy, and dry 
 sites, respectively. 
$
CL 0965
AU Wielgolaski, F.E.
; Webber, P.J.
DT 1973
TI Classification and ordination of circumpolar arctic and alpine vegetation
SO International Tundra Biome Newsletter, 9:24-31
DE Ecology
; U.S. International Biological Programme
; Angiosperms
; Community
; Phytosociology
AB None
$
CL 0966
AU Wiens, D.
; Halleck, D.K.
DT 1962
TI Chromosome numbers in Rocky Mountain plants
SO Botaniska Notiser, 115:455-464
DE Genetics
; University of Colorado
; Niwot Ridge
; Angiosperms
AB None
$
CL 0967
AU Wiens, D.
; Richter, J.A.
DT 1966
TI Artemisia pattersonii: a 14-chromosome species of alpine sage
SO American Journal of Botany, 53(10):981-986
DE Genetics
; University of Colorado
; Niwot Ridge
; Angiosperms
AB None
$
CL 1337
AU Williams M.W.
; Brooks P.D.
; Seastedt T.S.
DT 1998
TI Nitrogen and carbon soil dynamics in response to climate change
 in a high-elevation ecosystem in the Rocky Mountains, U.S.A
SO Arctic and Alpine Research 30:26-30
DE NWTLTER
; alpine tundra
; nitrogen 
; carbon
; snow-fence
AB We have implemented a long-term snow-fence experiment at the Niwot Ridge
 Long-Term Ecological Research (NWT) site in the Colorado Front Range of the
 Rocky Mountains, USA, to assess the effects of climate change on alpine 
 ecology and biogeochemical cycles. The responses of carbon (C) and nitrogen
 (N) dynamics in high-elevation mountains to changes in climate are investigated
 by manipulating the length and duration of snow cover with the 2.6 x 60m snow
 fence, providing a proxy for climate change. Results from the first year of
 operation in 1994 showed that the period of continuous snow cover was increased
 by 90 d. The deeper and earlier snowpack behind the fence insulated soils
 from winter air temperatures, resulting in a 9 degree C increase in annual
 minimum temperature at the soil surface. The extended period of snow cover
 resulted in subnivial microbial activity playing a major role in annual C
 and N cycling. The amount of C mineralized under the snow as measured by
 CO2 production was 22 g per m^2 in 1993 and 35 g per m^2 in 1994, accounting
 for 20% of annual net primary above-ground production before construction
 in 1994. In a similar fashion, maximum subnivial N2O flux increased 3-fold
 behind the snow fence, from 75 micrograms N per m^2 per d in 1993 to 
 250 micrograms N per m^2 per d in 1994. The amount of N lost from denitrification
 was greater than the annual atmospheric input of N in snowfall. Surface litter
 decomposition studies show that there was a significant increase in the litter
 mass loss under deep and early snow, with no significant change under medium
 and little snow conditions. Changes in climate that result in differences in 
 snow duration, depth, and extent may therefore produce large changes in the
 C and N soil dynamics of alpine ecosystems.
$
CL 1339
AU Williams M.W.
; Bardsley T.
; Rikkers M.
DT 1998
TI Overestimation of snow depth and inorganic nitrogen wetfall using NADP data,
 Niwot Ridge, Colorado
SO Atmospheric Environment 32(22):3827-3833
DE NWTLTER
; nitrogen
; snow
; precipitation
; alpine
; NADP
AB We evaluated precipitation quantity and inorganic N deposition from wetfall at the
 Saddle site on Niwot Ridge, an alpine location in the Colorado Front Range of the
 Rocky Mountains. The chemical content of precipitation was collected with an
 Aerometrics wet-only deposition collector and pre
2000
cipitation amount was collected in
 a co-located Fegusson-type weighing gauge with a wind shield. Calculating the actual
 deposition of snow at a point in alpine areas is difficult because wind transport
 can cause under sampling or over sampling of the actual precipitation amount. We used
 a moisture sensor on the wet chemistry collector to account for blowing snow events,
 categorizing snow and rain collected in the Saddle precipitation gauge as precipitation
 when the moisture sensor was "on" and blowing snow and rain events when the moisture
 sensor was "off". Over a ten-year period, 61% of the winter precipitation was collected
 when the moisture sensor was "off". Perhaps fortuitously, annual solid precipitation
 (October-May) of 1514 mm measured at the Saddle was 61% more than the 938 mm measured
 at an alpine site 2 km away and accounted for the difference in annual precipitation 
 amount at the two sites. Annual inorganic N deposition at the Saddle site was then
 calculated as the measured summer deposition amount added to the measured winter deposition
 adjusted for over sampling from blowing snow events. These correction factors resulted in
 a 32% reduction of annual inorganic N in wetfall for the period 1986-1995, from an
 arithmetic mean of 4.7 to 3.2 kg/ha/yr.
$
CL 0977
AU Williams, G.M.
; McCoy, M.C.
DT 1984
TI Forecast results of the PROFS 1983 Summer experiment
SO Preprint Volume: 10th Conference on Weather Forecasting and Analysis, June
 25-29, 1984, Clearwater Beach, Florida. Boston, Massachusetts: American
 Meteorological Society, 234-240
DE Climatology
; NOAA - Profs
; C-1 Climate Station
; Climate - Discussion of
AB None
$
CL 0979
AU Williams, L.D.
DT 1974
TI Simulation of Green Lakes snowmelt for 1973 and for ñ 50% changes in initial
 snowpack.
SO In: Carroll, T. and Caine, N., Volume and rate of stream discharge from an
 alpine snowpack. A final report to the Eisenhower Consortium for Western
 Environmental Forestry Research. Appendix 4,3 pp. + 16 pp., figs.
DE technical report
; Model
; Hydrology
; Institute of Arctic and Alpine Research
; Boulder Watershed and Rainbow Lakes
; Lake
; Snow
; Stream
; Watershed
AB None
$
CL 1508
AU Williams, M. W. 
; Manthorne, D. 
DT 2001
TI Class I areas at risk: Event-based nitrogen deposition to a high-elevation, western site
SO The Scientific World v. 1
DE NWTLTER
AB None
$
CL1450
AU Williams, M.W
; Hood, E.W.
; Ostberg, G.
; Francou, B.
; Galarraga, R.
DT 2001
TI Synoptic survey of surface water isotopes and nutrient concentrations, paramo high-elevation region, antisana ecological reserve, ecuador
SO Arctic, Antarctic, and Alpine Research vol. 33(4). pp.397-403
DE Antisana
; water
AB Here we provide baseline information on water isotopes and nutrient concentrations for channelized streams and wetlands from a paramo ecosystem in Antisana Ecological Reserve, Ecuador. Water samples were collected from wetland areas and compared to the nearby Rio Tumiguina. Stream water samples were also collected downstream from glacial source areas for 7 km (Rio Tumiguina) and 10 km (Rio Antisana). Water samples from the gauging station on the Rio Tumiguina (n = 4) and nearby wetlands (n = 4) showed significant differences for some nutrients and little difference for other nutrients. Nitrate (N03-N) concentrations were below 14 mg L-1 (1 mmol L-1) at both sites and not significantly different. Concentrations of ammonium (NH4-N) in both stream water and wetlands were much higher than N03-N concentrations. For example, NH4-N concentrations in stream water of 195 mg L-1 (14 mmol L-1) were 17 times that of	N03-N concentrations. In contrast to N03-N and NH4-N, there was a significant difference (P < 0.001) between concentrations of soluble reactive phosphate (SRP), with concentrations of SRP in the Rio Tumiguina of about 263 mg L-1 (8.2 mmol L-1) and below detection limits in wetlands. Dissolved organic carbon (DOC) concentrations in the Rio Tumiguina of 0.4 mg L-1 were quite low compared to the 23 mg L-1 of DOC from the paramo wetlands. At both stream transects, the o180 values decreased from glacial signatures of about ù -17%o near the glacial terminus to -13%o at distances of 7 to 10 km. Nitrate concentrations were at or below detection limits at all sampling sites. Ammonium concentrations were higher than N03-N concentrations in all samples. Concentrations of dissolved organic phosphorus (DOP) were almost as high as dissolved organic carbon (DOC) near the glacial outlets. Concentrations of dissolved organic nitrogen (DON) and DOC were near detection limits near the glacial outlets and then increased downstream.$
CL 1263
AU Williams, M.W.
; Bales, R.C.
; Brown, A.D.
; Melack, J.M.
DT 1995
TI Fluxes and transformations of nitrogen in a high-elevation catchment,
 Sierra Nevada
SO Biogeochemistry 28:1-31
DE NWTLTER
; alpine tundra
; N mineralization
; nitrification
; nitrogen 
; subalpine forest
; Emerald Lake
; Sierra Nevada
; deposition
AB The fluxes and transformations of nitrogen (N) were investigated from
 1985 through 1987 at the Emerald Lake watershed (ELW), a 120-ha high-
 elevation catchment located in the southern Sierra Nevada, California, 
 USA. Up to 90% of annual wet deposition of N was stored in the seasonal
 snowpack; NO3- and NH4+ were released from storage in the form of an
 ionic pulse, where the first fraction of meltwater draining from the
 snowpack had concentrations of NO3- and NH4+ as high as 28 ueq/L 
 compared to bulk concentrations of <5 ueq/L in the snowpack. The soil
 reservoir of organic N (81 keq/ha) was about ten times the N storage 
 in litter and biomass (12 keq/ha). Assimilation of N by vegetation was
 balanced by the release of N from soil mineralization, nitrification,
 and litter decay. Mineralization and nitrification processes produced
 1.1 keq/ha/yr of inorganic N, about 3-1/2 times the loading of N from
 wet and dry deposition. Less than 1% of the NH4+ in wet and dry
 deposition was exported from the basin as NH4+. Biological assimilation
 was primarily responsible for retention of NH4+ in the basin, releasing
 one mole of H+ for every mole of NH4+ retained and neutralizing about
 25% of the annual acid neutralizing capacity produced by mineral 
 weathering in the basin. Nitrate concentrations in stream waters
 reached an annual peak during the first part of snowmelt runoff, with
 maximum concentrations in stream water of 20 ueq/L, more than 4 times
 the volume-weighted mean annual concentrations of NO3- in wet
 deposition. This annual peak in stream water NO3- was consistent with
 the release of NO3- from the snowpack in the form of an ionic pulse;
 however soil processes occurring underneath the winter snowpack were
 another potential source of this NO3-. Concentrations of stream water
 NO3- during the summer growing season were always near or below 
 detection limits (0.5 ueq/L).
$
CL 1310
AU Williams, M.W.
; Brooks, P.D.
; Mosier, A.
; Tonnessen, K.A.
DT 1996
TI Mineral nitrogen transformations in and under seasonal snow in a 
 high-elevation catchment in the Rocky Mountains, United States
SO Water Resources Research 32(10): 3161-3171
DE NWTLTER
; nitrogen
; nitrate
; ammonium
; snowpack
; snowmelt;
; soil
AB In an effort to understand sources on nitrate (NO3-) in surface waters
 of high-elevation catchments, nitrogen (N) transformations in and under
 seasonal snow were investigated from 1993 to 1995 on Niwot Ridge, an
 alpine ecosystem at 3,500 m located in the Colorado Front Range of the 
 Rocky Mountains. Ammonium (NH4+) and NO3- labeled with 15N applied as 
 nonconservative tracers to the snow showed no evidence of nitrification
 in the snowpack. Furthermore, NH4+ movement through the amended snowpack
 was highly correlated with a conservative chloride tracer (r^2=0.99). In
 an unamended snowpack NH4+ concentrations in meltwater before contact with
 the ground were highly correlated with NO3- concentrations (r^2=0.98),
 which is consistent with no nitrification in the snowpack. The isotopically 
 labeled 15
2000
NH4+ applied to the snowpack was found in underlying soils,
 showing that NH4+ released from snow can be rapidly immobilized. Resin
 bag (mixed-bed ion-exchange resins) measurements (n=22) showed that 80%
 of the mobile inorganic N in unamended subnivial soils was NO3-. Measurements
 of KCl-extractable inorganic N from the surface soils showed that the highest
 values were prior to the initiation of snowmelt and lowest values were during
 the growing season. The natural delta 15N abundance of unamended soils was
 negative and ranged from -12 to -2, suggesting that atmospheric deposition
 of delta 15N-depleted N is an important component of N cycling in these
 alpine soils. These results suggest that soil mineralization under seasonal
 snow, rather than snowmelt release of NO3-, may control NO3- concentrations
 in surface waters of high-elevation catchments.
$
CL 1306
AU Williams, M.W.
; Losleben, M
; Caine N.
; Greenland, D.
DT 1996
TI Changes in climate and hydrochemical responses in a high-eleveation 
 catchment in the Rocky Mountains, USA
SO Limnology and Oceanography 41(5): 939-946
DE NWTLTER
; climate
; hydrochemistry
; alpine
; snowpack
; acidification
; wet deposition
AB A continuous climate record since 1951 at Niwot Ridge in the Colorado
 Front Range shows a decline in mean annual temperature, an increase in
 annual precipitation amount, and a decrease in mean daily solar radiation
 for the summer months. The increase in precipitation amount explains about
 half of the 200% increase in annual wet deposition of NO3- to Niwot Ridge
 over the last decade. Differences in climate parameters between 1994 and
 1995 (increased snow depth and decreased net energy flux to the snowpack)
 resulted in a 4-5 fold increase in the magnitude of solute release from
 the snowpack in the form of an ionic pulse. In turn, the high chemical
 loading of strong acid anions in the seasonal snowpack and release of these
 solutes from the seasonal snowpack in the form of an ionic pulse is causing
 episodic acidification (ANC < 0meq/liter) in headwater catchments at
 present deposition levels. Small changes in climate parameters may cause
 large changes in the hydrochemistry of alpine streams. The changes in climate
 at Niwot Ridge are not in synchrony with lowland warming in the Great
 Plains to the east and serve as a reminder that climate in alpine areas
 is driven by local conditions and may be asynchronous with regional and
 global climate trends.
$
CL 1428
AU Williams, M.W.
; Caine, N.
DT 2001
TI Hydrology and hydrochemistry in alpine dynamics. 
SO In: The structure and function of an alpine ecosystem: Niwot Ridge
, Colorado. Bowman, W. and T.R. Seastedt (eds.). Oxford University Press
DE none
AB none
$
CL 1409
AU Williams, M.W.
; Brooks, P.D.
; Mosier, A.
; Tonnessen, K.A.
DT 1996
TI Mineral nitrogen transformationsin and under seasonal snow in a 
   high-elevation catchment in the Rocky Mountians, USA
SO Water Resources Research 32(10): 3161-3171.
DE None
AB None
$
CL 1367
AU Williams, M.W.
; Cline, D.
; Hartman, M.A.
; Bardsley, T.
DT 1999
TI Data for snowmelt model development, calibration, and verfication
 at an alpine site, Colorado Front Range
SO Water Resources Research 35:3205-3209
DE NWTLTER
; snowmelt
; data
; calibration
AB Logistical constraints have caused data collection in seasonally snow covered
 areas to generally be on a campaign basis with limited instrumentation. The
 problems of winter access, cold air temperatures, and blowing snow cause both
 equipment malfunctions and problems with consistent and timely maintenance.
 At the Long-Term Ecological Research program network site in an alpine area
 of Colorado we have been operating a meteorological station and subnivean
 (below snow) laboratory at 3517m since the spring of 1994 to collect information
 that will allow us to better understand snow-surface energy exchanges and the
 mass flux of water during snowmelt. This unique and high-quality data set was
 designed to measure the meteoroligic and hydrologic parameters necessary to
 compute the surface energy and snowpack mass balances at a point. All 
 meteorological parameters are directly measured. Turbulent fluxes are calculated
 using the aerodynamic profile method. The timing and magnitude of snowmelt is
 measured with 18 snow lysimeters. Meteorlogic parameters and energy fluxes
 are available at 10-min, hourly, and daily time steps. Complementary information 
 includes a high-resolution digital elevation model, snowpack parameters, and 
 stream discharge.
$
CL 1327
AU Williams, M.W.
; Davinroy, T.
; Brooks, P.D.
DT 1997
TI Organic and inorganic nitrogen pools in talus fields and subtalus water, 
 Green Lakes Valley, Colorado Front Range.
SO Hydrological Processes 11: 1747-1760
DE NWTLTER
; organic nitrogen
; inorganic nitrogen
; talus fields
; subtalus water
; alpine
; snow
; Colorado Front Range
AB Organic and inorganic pools of nitrogen (N) were measured in talus
 fines or 'soils' and subtalus water during the summer of 1995 in the
 alpine Green Lakes Valley catchment of the Colorado Front Range.
 Nineteen talus soil samples were divided into four classes: subtalus
 dry, subtalus wet, surface vegetated and surface bare.  The size of the
 individual talus soil patches ranged from 0.5 to 12.0 m^2 in area, with
 bulk density ranging from 0.98 to 1.71 kg m^-3 and soil texture ranging
 from sandy gravel in the subsurface talus to a loam in the vegetated
 surface.  All samples contained KCl-extractable NH4+ and NO3-, organic N
 and carbon (C), and 17 of 19 samples contained microbial biomass.  The
 mean subtalus values for KCl-extractable NH4+, of 3.2 mg N kg^-1, and
 NO3-, of 1.0 mg N kg^-1, were comparable with developed alpine soils 
 on Niwot Ridge.  Average microbial biomass in subtalus soils of 
 5.4 mg N kg^-1 and total N of 1000 mg N kg^-1 were about an order of 
 magnitude lower than alpine tundra soils, reflecting the reduced amount 
 of vegetation in talus areas.  However, these measurements in 
 surface-vegetated patches of talus were comparable with the well-developed 
 soils on Niwot Ridge.  These measurements in talus of microbial biomass, 
 total N and KCl-extractable NH4+ and NO3-, show that there is sufficient 
 biotically conditioned 'soil' within talus fields to influence the solute 
 content of interstitial waters.  Mean NO3- concentrations of 20 ueq l^-1 
 from 29 samples of subtalus water were significantly higher than the 
 6.7 ueq l^-1 in snow, while NH4+ concentrations in subtalus water of 
 0.7 ueq l^-1 was significantly lower than in snow at 5.2 ueq l^-1 
 (p = 0.001). Nitrate concentrations in subtalus water were significantly 
 (p < 0.0001) correlated with concentrations of geochemical weathering 
 products such as Ca2+ (r^2 = 0.84) and silica (r^2 = 0.49). The correlation 
 of NO3- in subtalus water with geochemical weathering products suggests 
 that NO3- concentrations in subtalus water increased with increased residence 
 time, consistent with a biological source for this subtalus water NO3-. The 
 high NO3- concentrations in subtalus water compared with atmospheric 
 deposition of NO3- suggests that NO3- in talus fields may contribute to 
 NO3- in stream waters of high-elevation catchments. 
$
CL 1292
AU Williams, M.W.
; Baron, J.S.
; Caine, N.
; Sommerfeld, R.
; Sanford, R.
DT 1996
TI Nitrogen saturation in the Rocky Mountains
SO Environmental Science and Technology 30 (2):640-646
DE NWTLTER
; Niwot Ridge
; Green Lakes Valley
; Rocky Mountains
; nitrogen
; nitrate 
; high-elevation catchments
; bristlecone pine
AB Nitrogen saturation is occurring throughout high-elevation catchments 
 of the Colorado Front Range. Annual inorganic N loading in wet deposition 
 to the Front Range of approximately 4 kg per ha per year is about twice that
 of the Pacific States and similar to many sites in the northeastern United
 States. In the last ten years at Niwot Ridge/Green Lakes Valley and Glacier
 Lakes, annual minimum concentrations o
2000
f NO3- in surface waters during the
 growing season have increased from below detection limits to approximately
 10 microequiv per liter, indicating that these two catchments are at the 
 threshold of N saturation. The Lock Vale watershed is N saturated, with 
 annual minimum concentrations of NO3- in surface waters generally above 10 
 microequiv per liter; annual volume-weighted mean (VWM) concentration of 
 16 microequiv per liter in surface waters are greater than that of 
 approximately 11 microequiv per liter NO3- in wet deposition. At these 
 high-elevation catchments, there has been a shift in ecosystem dynamics 
 from an N-limited system to an N-saturated system as a result of 
 anthropogenically fixed N in wetfall and dryfall. Results from the Western 
 Lakes Survey component of the National Surface Water Survey show that N
 saturation is a regional problem in the Colorado Front Range, with many
 Lakes having (NO3-) concentrations greater than 10 microequiv per liter.
 Foliar N:P ratios in bristlecone pine increase with elevation in the
 Colorado Front Range, indicating that at higher elevations P is translocated
 from foliar tissue more efficiently than N and that increasing atmospheric
 deposition of N with elevation is causing a change from N limitations to
 P limitation in the highest-elevation bristlecone pines. Current concepts
 of critical loads need to bve reconsidered since only modest atmospheric
 loadings of N are sufficient to induce N leaching to surface waters
 in high-elevation catchments of the western United States.
$
CL 1390 
AU Williams, M.W.
; Tonnessen, K.A.
DT 2000
TI Critical loads for inorganic nitrogen deposition in the Colorado Front Range,USA
SO Ecological Aplications 10(6):1648-1665
DE NWTLTER
AB None
$
CL1449
AU Williams, M.W.
; Hood, E.
; Caine, N.
DT 2001
TI Role of organic nitrogen in the nitrogen cycle of a high-elevation catchment, Colorado Front Range
SO Water Resources Research vol. 37 (10). pp.2569-2581
DE NWTLTER
; Nitrogen
; DON
AB Here we report on 3 years (1996ù1998) of measurements of organic and inorganic nitrogen (N) fluxes to and from Green Lakes Valley, a high-elevation ecosystem in the Colorado Front Range of the Rocky Mountains. Nitrate-N (N03-N) was the dominant form of N in both precipitation and stream water. Annual precipitation contained 52% N03-N, 32% ammonium-N (NH4-N), 9% dissolved organic N (DON), and 7% particulate organic N (PON). Annual export of N in streamfiow was composed of 70% N03-N, 4% NH4-N, 14% DON, and 12% PON. Thus the percentage of organic N increased from 16% of total N in precipitation to 26% of total N in streamflow. Subtracting inputs from outputs, Green Lakes Valley always shows net retention of inorganic N. The only form of N that showed net export was DON. DON export was low (0.18 to ù0.13 kg ha-1 yr-1), with net export recorded in 2 years and basin retention recorded in 1 year. There was a seasonal pattern in the concentrations of inorganic N (N03-N ˜ NH4-N) and organic N (DON + PON). Concentrations of inorganic N were ~15ù25 mmol L-1 during base flow, increased to ~30 mmol L-1 on the rising limb of the hydrograph during snowmelt runoff, then decreased to ~5 mmol L-1 on the recession limb of late summer, with a return to base flow values in the autumn. In contrast, organic N was 7ù15 mmol L-1 during base flow and decreased to near or below detection limits on the rising limb of the hydrograph, with a gradual but consistent increase on the recession limb and on into the autumn. The amount of N in dissolved organic matter changed over time, with the dissolved organic carbon (DOC):DON ratio decreasing from ~45 on the rising limb of the hydrograph to <20 in the autumn. Spatially, there was a striking difference in the ratios of N03-N and DON between talus and tundra areas. Nitrate concentrations in surface water draining talus areas were always greater than DON. In contrast, DON concentrations in surface water draining tundra areas were always greater than N03-N. Concentrations of DON were not significantly correlated with DOC (R2 = 0.04, p > 0.05), indicating that controls on DON export may be different than controls on DOC export. Our results suggest that the ratio of the annual mass flux of inorganic N to organic N in stream waters may provide a novel index to evaluate the N status of terrestrial ecosystems from various biomes.
$
CL 1509
AU Williams, M.W.
;  Hood, E.
;  Caine, N. 
DT 2003
TI Headwater catchments of the Boulder Creek Watershed
SO Chapter 8 in Murphy, S.F., Verplanck, P.L., and Barber, L.B., Eds., Comprehensive water quality of the Boulder Creek Watershed, Colorado, during high-flow and low-flow conditions, 2000: U.S.  Geological Survey Water Resources Investigations Report 03-4045, pp 185-197.
DE NWTLTER
AB None
$
CL 1391 
AU Williams, M.W.
; Rikkers, M.R.
; Pfeffer, W.T.
DT 2000
TI Ice columns and frozen rills in a warm snowpack, Green Lakes Valley, Colorado, USA
SO Nordic Hydrology 31(3):169-186
DE NWTLTER
AB None
$
CL 1287
AU Williams, M.W.
; Yang, D.
; Liu, F.
; Turk, J.
; Melack, J.
DT 1995
TI Controls on the major ion chemistry of the Urumqi River, Tian Shan, People's 
 Republic of China
SO Journal of Hydrology 172:209-229
DE NWTLTER
; China
; Tian Shan
; hydrology
; hydrochemistry
; calcium
; carbonic acid
; sulfate
AB Water and snow samples were collected in May of 1990 and 1992 in headwater basins
 and along a longitudinal transect of the Urumqi River, located in northwestern China.
 Surface waters were dominated by Ca++ and HCO3- at all sites. Maximum measured SO4--
 concentrations in surface waters were 550 ueq/L, and were balanced by Ca++ and HCO3-;
 pH was slightly alkaline at all locations. Several independent analyses each concluded
 that the solute composition of surface waters was dominated by dissolutions of rocks 
 with rapid weathering kinetics, such as calcite and dolomite. Preliminary analysis of
 stable sulfur ratios in headwater basins shows delta 34 S values of +6.8 for snow and
 +3.3 for surface waters. Changes is the delta 34 S value of surface waters with 
 increasing basin area were variable, suggesting changes in the stable sulfur ratios
 of source materials. The large amounts of HCO3- and base cations at all sites indicates
 that the Urumqi River is not sensitive to acidification from atmospheric deposition.
$
CL 1487
AU Williams, M.W.
; Losleben, M.V.
; Hamann, H.B.
DT 2003
TI Alpine Areas in the Colorado Front Range as Monitors of Climate Change and Ecosystem Response
SO The Geographic Review v. 92(2) pp. 180-191
DE NWTLTER
; alpine
; bighorn sheep
; biogeochemistry shift
; climate change
; nitrogen
; water acidification
AB The presence of a seasonal snowpack in alpine environments can amplify climate signals. A conceptual model is developed for the response of alpine ecosystems in temperate, midlatitude areas to changes in energy, chemicals, and water, based on a case study from Green Lakes Valley-Niwot Ridge, a headwater catchment in the Colorado Front Range. A linear regression shows the increase in annual precipitation of about 300 millimeters from 1951 to 1996 to be significant. Most of the precipitation increase has occurred since 1967. The annual deposition of inorganic nitrogen in wetfall at the Niwot Ridge National Atmospheric Deposition Program site roughly doubled between 1985-1988 and 1989-1992. Storage and release of strong acid anions, such as those from the seasonal snowpack in an ionic pulse, have resulted in episodic acidification of surface waters. These biochemical changes alter the quantity and quality of organic matter in high-elevation catchments of the Rocky Mountains. Affecting the bottom of the food chain, the increase in nitrogen deposition may be partly responsible for the current decline of bighorn sheep in the Rocky Mountains.
$
CL 1368
AU Williams, M.W.
; Sommerfeld, R.
; Massman, S.
; Rikkers, M.
DT 1999
TI Correlation lengths of melwater flow through ripe snowpacks, 
 Colorado Front Range, USA
SO Hydrological Processes 13:1807-1826
DE NWTLTER
; meltwat
2000
er
; snow grain size
AB The flowpaths of meltwater through snow is known to be an inhomogeneous
 process. The spatial distribution of meltwater flowing from the bottom 
 of melting snowpacks is the result of horizontal and vertical flow paths
 within the snowpack. The ability to characterize the spatial distribution
 of these meltwater flowpaths would be useful in developing models of snow
 melt runoff which could better characterize snow melt hydrographs. We 
 analyzed near infrared aerial photos of melting snow using a moving window
 analysis which can characterize correlation lengths in the reflectance of 
 the snow surface. Near infrared is sensitive to snow grain size, which in
 turn may indicate higher amounts of meltwater; the grains grow faster if the
 liquid water content is higher. Correlation lengths were five to seven meters
 and the probability of finding such correlation lengths increased from 0.22 
 in May 1997 when the melt had just started to 0.68 by late June when melt
 was well established. Liquid water content at the snow surface was sampled 
 with a dielectric sensor at 0.5m intervals on 100m^2 and 75m^2 grids. 
 Semi-variograms showed a sill at five to six metres. The liquid water 
 measurements at the snow surface suggest that the correlation lengths derived 
 from the infrared aerial photos represent surface expressions of higher flow 
 density through the melting snowpack. A circular array of 16 snow melt 
 lysimeters each with areas of 0.2m^2 was operated for two years at Niwot 
 Ridge in the Colorado Front Range. Variograms indicated that flows were 
 correlated over a distance of five to seven metres. These three independent 
 methods all suggest a spatial organization of five to seven metres for 
 flowpaths draining ripe snowpacks in the Rocky Mountains.
$
CL 1513
AU Williams, M.W. 
; Knoll, M.
DT 2002
TI Measuring material properties of a wet and draining snowpack using crosshole radar tomography
SO Proceedings of the 70th Western Snow Conference, pp 49-57, Granby, Colorado, 2002
DE NWTLTER
AB None
$
CL 0980
AU Williams, R.E.
DT 1977
TI Distribution, ecology, and reproductive cycles of Colorado fresh-water
 sponges (porifera: spongillidae)
SO Ph.D. dissertation, University of Colorado, Boulder. 155 pp.
DE Dissertation
; Ecology
; University of Colorado
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Altitude
; Lake
; Distribution
; Reproduction
AB None
$
CL 0983
AU Windell, J.T.
; Light, J.T.
DT 1984
TI Age and growth of alpine brook trout populations, Green Lakes Valley,
 Colorado Front Range
SO Bulletin of Ecological Society of America, 65(2):132. Abstract
DE Ecology
; Long Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Fish
; Demography
; Growth (Development)
AB None
$
CL 0981
AU Windell, J.T.
; Bushnell, J.H.
; Butler, N.
; Caine, N.
DT 1982
TI Elevational contrasts in the alpine lakes of Green Lakes Valley, Colorado
 Front Range
SO Joint Symposium on Long-Term Ecological Research. Ecological Bulletin,
 63(2):119. Abstract
DE Abstract
; Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Invertebrates
; Fish
; Altitude
; Lake
; Distribution
; Diversity
; Plankton
AB None
$
CL 0982
AU Windell, J.T.
; Foster, S.Q.
DT 1982
TI The status of unexploited fish populations in the Green Lakes Valley, an
 alpine watershed, Colorado Front Range
SO In: Halfpenny, J.C. (ed.), Ecological Studies in the Colorado Alpine: A
 Festschrift for John W. Marr. University of Colorado, Institute of Arctic and
 Alpine Research, Occasional Paper, 37:133-137
DE Ecology
; Long-Term Ecological Research Program
; Boulder Watershed and Rainbow Lakes
; Fish
; Demography
; Distribution
; NWTLTER
AB None
$
CL 1482
AU Winstral, A
; Elder, K.
; Davis, R.E.
DT 2002
TI Spatial Snow Modeling of Wind-Redistributed Snow Using Terrain-Based Parameters
SO Journal of Hydrometeorology v. 3 pp. 524-538
DE Wind
; modeling
; snow
; MOUNTAIN BASIN
; BLOWING SNOW
; ALPINE
; HYDROLOGY
; RADIATION
; PRAIRIE
; COVER
AB Wind is widely recognized as one of the dominant controls of snow accumulation and distribution in exposed alpine regions. Complex and highly variable wind fields in rugged terrain lead to similarly complex snow distribution fields with areas of no snow adjacent to areas of deep accumulation. Unfortunately, these complexities have limited inclusion of wind redistribution effects in spatial snow distribution models. In this study the difficulties associated with physically exhaustive wind field modeling are avoided and terrain-based parameters are developed to characterize wind effects. One parameter, (Sx) over bar, was based on maximum upwind slopes relative to seasonally averaged winds to characterize the wind scalar at each pixel location in an alpine basin. A second parameter, (Sb) over bar measured upwind breaks in slope from a given location and was combined with an upwind application of (Sx) over bar to create a drift delineator parameter, D-0, which was used to delineate sites of intense redeposition on lee slopes. Based on 504 snow depth samples from a May 1999 survey of the upper Green Lakes Valley, Colorado, the correlation of the developed parameters to the observed snow distribution and the effect of their inclusion in a spatial snow distribution model were quantified. The parameter (Sx) over bar was found to be a significant predictor, accounting for more of the variance in the observed snow depth than could be explained by elevation, solar radiation, or slope. Samples located in D-0-delineated drift zones were shown to have significantly greater depths than samples located in nondrift zones. A regression tree model of snow distribution based on a predictor variable set of (Sx) over bar, D-0, elevation, solar radiation, and slope explained 8%-23% more variance in the observed snow distribution, and performed noticeably better in unsampled areas of the basin, compared to a regression tree model based on only the latter three predictors.$
CL 0984
AU Wojciechowski, M.F.
DT 1981
TI Biological nitrogen fixation in the alpine tundra of the Front Range of the
 Colorado Rocky Mountains
SO Ph.D. dissertation, University of Northern Colorado, Greeley. 108 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Angiosperms
; Community
; Nitrogen
AB None
$
CL 0985
AU Wojciechowski, M.F.
; Heimbrook, M.E.
DT 1984
TI Dinitrogen fixation in alpine tundra, Niwot Ridge, Front Range, Colorado,
 U.S.A.
SO Arctic and Alpine Research, 16:1-10
DE Ecology
; Niwot Ridge
; Angiosperms
; Community
; Nitrogen
; Mountain Research Station - Affiliation
AB None
$
CL 0986
AU Wolfenden, P.J.
; Lewin, J.
DT 1978
TI Distribution of metal pollutants in active stream sediments
SO Catena, 5:67-78
DE Hydrology
; Niwot Ridge
; Boulder Watershed and Rainbow Lakes
; Stream
; Chemistry
; Pollution
; Indian Peaks Region
AB None
$
CL 1243
AU Woodhouse, C.A.
DT 1993
TI Tree-growth response to ENSO events in the central Colorado Front Range
SO Physical Geography 14:417-435
DE NWTLTER
; El Nino-Southern Oscillation
; dendrochronology
; Colorado Front Range
AB The influence of climate associated with El Nino/Southern Oscillation (ENSO)
 events on tree growth in the central Colorado Front Range is investigated
 through analysis of two high altitude tree-ring chronologies.
 Dendrochronological techniques are used to determine if ENSO-related climatic
 effects are detectable in tree-ring width patterns in the central Colorado
 Front Range. The form of the tree-growth response is identified and the
 variability of the influence of these events on tree growth over time is
 investigated. Results indicate that tree growth in this area does respond to
 ENSO events, but the response varies with species and type of event. El
 Nino-influenced climate tends to result in larger tree rings the year of or
 year following the event, while La Nina-influenced climate tends to result in
 smaller rings the 
14ac
year after the event, reflecting spring moisture conditions.
 Trees have a more consistent response to La Nina events, but El Nino events
 seem to have a greater effect on extremes in growth. The relationship between
 the Southern Oscillation Index (SOI) and tree growth has varied over time,
 probably because of the fact that ENSO events, characterized by the SOI, vary
 in magnitude and amplitude.
$
CL 0987
AU Woodmansee, R.G.
DT 1972
TI Soil descriptions and simulation model of potassium cycling in Colorado
 forests
SO Ph.D. dissertation, Colorado State University Fort Collins. 160 pp.
DE Dissertation
; Model
; Ecology
; Soil sciences
; Mountain Research Station - Affiliation
; Conifers
; Soil
; Nutrients
AB None
$
CL 0988
AU Worchester, P.G.
DT 1920
TI The geology of the Ward Region, Boulder County, Colorado
SO M.A. thesis, University of Colorado, Boulder. 74 pp.
DE Thesis
; Geology
; University of Colorado
; Indian Peaks Region
AB None
$
CL 0989a
AU Yamaguchi, D.K.
DT 1990
TI On "climate variability and tree response within the forest alpine tundra
 ecotone" by Hansen-Bristow, Ives, and Wilson
SO Annals of the Association of American Geographers 80:285-290
DE article
; ecology
; Long-Term Ecological Research Program
; Niwot Ridge
; conifers
; climate - discussion of
; forest-tundra ecotone
; growth
; tree
; demography
; NWTLTER
AB None
$
CL 0990
AU Youmans, G.R.
DT 1980
TI Assessment of denitrification in meadow soils from regional ecosystems of
 the Colorado Front Range
SO Ph.D. dissertation, University of Northern Colorado, Greeley. 103 pp.
DE Dissertation
; Ecology
; Mountain Research Station - Affiliation
; Niwot Ridge
; Soil
; Nitrogen
; Ecosystem
AB None
$
CL 0991
AU Young, R.T.
DT 1907
TI The forest formations of Boulder County, Colorado
SO Botanical Gazette, 44:321-352
DE Ecology
; History
; U.S. International Biological Programme
; Boulder Watershed and Rainbow Lakes
; Conifers
; Tree
; Fire
AB None
$
CL 1524
AU Yulsman, T. 
DT 1999
TI  Twisted trees
SO  Audubon. Nov/Dec, Vol. 101 Issue 6 pp. 30-35
DE NWTLTER
AB None
$
CL 1259
AU Zak, D.R.
; Tilman, D.
; Parmenter, R.R.
; Rice, C.W.
; Fisher, F.M.
; Vose, J.
; Milchunas, D.
; Martin, C.W.
DT 1994
TI Plant production and soil microorganisms in late-successional
 ecosystems: A continental-scale study
SO Ecology 75:2333-2347
DE NWTLTER
; aboveground net primary production
; carbon and nitrogen cycles
; heterotrophic metabolism
; labile organic matter
; microbial respiration
; net N mineralization
; soil microbial biomass
; soil microorganisms
; soil texture
; substrate-use efficiency
AB Annual C inputs from plant production in terrestrial ecosystems
 only meet the maintenance energy requirements of soil microorganisms, 
 allowing for little or no net annual increase in their biomass. 
 Because microbial growth within soil is limited by C availability, 
 we also reasoned that soil texture should further modify the influence 
 of plant productiion on soil C availability because fine-textured 
 soils typically support more microbial biomass than coarse-textured 
 soils. To test these ideas, we quantified the relationship between 
 aboveground net primary production (ANPP) and soil microbial biomass 
 in late-successional ecosystems distributed along a continent-wide 
 gradient in North America. We also measured labile pools of C and N 
 within the soil because they represent potential substrate for 
 microbial activity. Ecosystems ranged from a Douglas-fir forest in 
 the western United States to the grasslands of the mid-continent to 
 the hardwood forests in the eastern U.S. Estimates of ANPP obtained 
 from the literature ranged from 82 to 1460 g/m^2/yr. Microbial biomass 
 C and N and first-order rate constants for microbial respiration and 
 net N mineralization were estimated using a long-term (32 wk) 
 laboratory incubation. Regression analyses were used to relate ANPP 
 and soil texture with microbial biomass and labile soil C and N pools. 
 Microbial biomass carbon ranged from 2 g/m^2 in the desert grassland 
 to 134 g/m^2 in the tallgrass prairie; microbial N displayed a similar 
 trend among ecosystems. Labile C pools, derived from a first-order 
 rate equation, ranged from 115 g/m^2 in the desert grassland to 491 
 g/m2 in the southern hardwood forest. First-order rate constants for 
 microbial respiration (k) fell within a narrow range of values (0.180 
 to 0.357 per wk), suggesting that labile C pools were chemically
 similar among this diverse set of ecosystems. Potential net N
 mineralization rates over the 32-wk incubation were linear in most
 ecosystems with first-order responses only in the alpine tundra,
 tallgrass prairie, and forests. Microbial biomass C displayed 
 a positive, linear relationship with ANPP (r^2=0.51), but was not
 significantly related to soil texture. Labile C also was linearly
 related to ANPP (r^2=0.32) and to soil texture (r^2=0.33). Results
 indicate that microbial biomass and labile organic matter pools
 change predictably across broad gradients of ANPP, supporting the
 idea that microbial growth in soil is constrained by C availability.
$
.

0