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Publications

Below is a list of available NOROCK peer reviewed and published science. If you are in search of a specific publication and cannot find it below or through a search, please contact twojtowicz@usgs.gov.

Filter Total Items: 1308

The influence of diet on faecal DNA amplification and sex identification in brown bears (Ursus arctos) The influence of diet on faecal DNA amplification and sex identification in brown bears (Ursus arctos)

To evaluate the influence of diet on faecal DNA amplification, 11 captive brown bears (Ursus arctos) were placed on six restricted diets: grass (Trifolium spp., Haplopappus hirtus and Poa pratensis), alfalfa (Lupinus spp.), carrots (Daucus spp.), white-tailed deer (Odocoileus virginianus), blueberries (Vaccinium spp.) and salmon (Salmo spp.). DNA was extracted from 50 faecal samples of...
Authors
M.A. Murphy, L.P. Waits, K.C. Kendall

Fire and aquatic ecosystems of the western USA: Current knowledge and key questions Fire and aquatic ecosystems of the western USA: Current knowledge and key questions

Understanding of the effects of wildland fire and fire management on aquatic and riparian ecosystems is an evolving field, with many questions still to be resolved. Limitations of current knowledge, and the certainty that fire management will continue, underscore the need to summarize available information. Integrating fire and fuels management with aquatic ecosystem conservation begins...
Authors
P.A. Bisson, B. Rieman, C. Luce, Paul F. Hessburg, D. Lee, J. Kershner, G.H. Reeves, Robert E. Gresswell

Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss

We examined spatial and temporal patterns of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, O. mykiss, in streams of the Flathead River system in Montana, U.S.A. We detected hybridization in 24 of 42 sites sampled from 1998 to 2001. We found new Oncorhynchus mykiss introgression in seven of 11 sample populations that were...
Authors
Nathaniel P. Hitt, Christopher A. Frissell, Clint C. Muhlfeld, Fred W. Allendorf

Ecological implications of bovine tuberculosis in African Buffalo herds Ecological implications of bovine tuberculosis in African Buffalo herds

Following the recent invasion of bovine tuberculosis (BTB) into the Kruger National Park, South Africa, we conducted a study on the maintenance host, African buffalo, to investigate associations between BTB prevalence and calf:cow ratio, age structure, body condition, and endoparasite load. Statistical analyses compared herds of zero, medium (1–40%), and high (>40%) BTB prevalence. To...
Authors
Alex Caron, Paul C. Cross, Johan T. du Toit

Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana

We evaluated the diel habitat use and movement of subadult bull trout Salvelinus confluentus by use of radiotelemetry during winter in the upper Flathead River, Montana. Of the 13 monitored bull trout, 12 (92%) made at least one diel movement to other habitat locations during their respective day–night tracking surveys and moved an average of 73% of the time. The median distance moved...
Authors
Clint C. Muhlfeld, Steve Glutting, Rick Hunt, Durae Daniels, Brian Marotz

Endangered toads in the Rockies Endangered toads in the Rockies

The western toad species complex, endemic to western North America, includes two montane species that have undergone extensive declines. These are the Yosemite toad, Bufo canorus, in the Sierra Nevada, and the southern Rocky Mountain populations of the boreal toad, B. borea. Most declines in the Rockies appear to have occurred before 1980, but a recent episode in Rocky Mountain National...
Authors
Paul Stephen Corn

Use of sulfur and nitrogen stable isotopes to determine the importance of whitebark pine nuts to Yellowstone grizzly bears Use of sulfur and nitrogen stable isotopes to determine the importance of whitebark pine nuts to Yellowstone grizzly bears

Whitebark pine (Pinus albicaulis) is a masting species that produces relatively large, fat- and protein-rich nuts that are consumed by grizzly bears (Ursus arctos horribilis). Trees produce abundant nut crops in some years and poor crops in other years. Grizzly bear survival in the Greater Yellowstone Ecosystem is strongly linked to variation in pine-nut availability. Because whitebark...
Authors
L.A. Felicetti, C.C. Schwartz, R. O. Rye, M.A. Haroldson, K.A. Gunther, D.L. Phillips, C.T. Robbins

Modeled climate-induced glacier change in Glacier National Park, 1850-2100 Modeled climate-induced glacier change in Glacier National Park, 1850-2100

The glaciers in the Blackfoot–Jackson Glacier Basin of Glacier National Park, Montana, decreased in area from 21.6 square kilometers (km2) in 1850 to 7.4 km2 in 1979. Over this same period global temperatures increased by 0.45°C (± 0.15°C). We analyzed the climatic causes and ecological consequences of glacier retreat by creating spatially explicit models of the creation and ablation of...
Authors
M.H.P. Hall, D.B. Fagre

Taking the pulse of mountains: Ecosystem responses to climatic variability Taking the pulse of mountains: Ecosystem responses to climatic variability

An integrated program of ecosystem modeling and field studies in the mountains of the Pacific Northwest (U.S.A.) has quantified many of the ecological processes affected by climatic variability. Paleoecological and contemporary ecological data in forest ecosystems provided model parameterization and validation at broad spatial and temporal scales for tree growth, tree regeneration and...
Authors
Daniel B. Fagre, David L. Peterson, Amy E. Hessl

Feedback-driven response to multidecadal climatic variability at an alpine treeline Feedback-driven response to multidecadal climatic variability at an alpine treeline

The Pacific Decadal Oscillation (PDO) has significant climatological and ecological effects in northwestern North America. Its possible effects and their modification by feedbacks are examined in the forest-tundra ecotone in Glacier National Park, Montana, USA. Tree ring samples were collected to estimate establishment dates in 10 quadrats. Age-diameter regressions were used to estimate...
Authors
K.J. Alftine, G.P. Malanson, D.B. Fagre

Large wood recruitment and redistribution in headwater streams in the southern Oregon Coast Range, U.S.A Large wood recruitment and redistribution in headwater streams in the southern Oregon Coast Range, U.S.A

Large wood recruitment and redistribution mechanisms were investigated in a 3.9 km2 basin with an old-growth Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. forest, located in the southern Coast Range of Oregon. Stream size and topographic setting strongly influenced processes that delivered wood to the channel network. In small colluvial channels draining steep...
Authors
Christine L. May, Robert E. Gresswell
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