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: 1216
Spatial and temporal variability in the amount and source of dissolved organic carbon: Implications for ultraviolet exposure in amphibian habitats
The amount, chemical composition, and source of dissolved organic carbon (DOC), together with in situ ultraviolet (UV-B) attenuation, were measured at 1–2 week intervals throughout the summers of 1999, 2000, and 2001 at four sites in Rocky Mountain National Park (Colorado). Eight additional sites, four in Sequoia and Kings Canyon National Park/John Muir Wilderness (California) and four in Glacier
Authors
P. D. Brooks, C. M. O'Reilly, S. A. Diamond, K. Campbell, R. Knapp, D. Bradford, P. S. Corn, B. Hossack, K. Tonnessen
Topography and vegetation as predictors of snow water equivalent across the alpine treeline ecotone at Lee Ridge, Glacier National Park, Montana, U.S.A.
We derived and implemented two spatial models of May snow water equivalent (SWE) at Lee Ridge in Glacier National Park, Montana. We used the models to test the hypothesis that vegetation structure is a control on snow redistribution at the alpine treeline ecotone (ATE). The statistical models were derived using stepwise and “best” subsets regression techniques. The first model was derived from fie
Authors
C. A. Geddes, Daniel G. Brown, Daniel B. Fagre
Yellowstone bison fetal development and phenology of parturition
Knowledge of Yellowstone bison (Bison bison) parturition patterns allows managers to refine risk assessments and manage to reduce the potential for transmission of brucellosis between bison and cattle. We used historical (1941) and contemporary (1989–2002) weights and morphometric measurements of Yellowstone bison fetuses to describe fetal growth and to predict timing and synchrony of parturition.
Authors
P.J.P. Gogan, K.M. Podruzny, E.M. Olexa, H.I. Pac, K.L. Frey
Assessing American black bear habitat in the Mobile-Tensaw Delta of southwestern Alabama
American black bears (Ursus americanus) have been extirpated from all but a few areas in southwestern Alabama, and the remaining habitat is being rapidly lost to development. Remnant bear populations exist near extensive (>125,000 ha) bottomland hardwood forests in the Mobile–Tensaw Delta (MTD), but those bottomland areas are rarely used by bears. Reintroduction of black bears to the MTD may impro
Authors
K.R. Hersey, A.S. Edwards, J. D. Clark
Consumption of pondweed rhizomes by Yellowstone grizzly bears
Pondweeds (Potamogeton spp.) are common foods of waterfowl throughout the Northern Hemisphere. However, consumption of pondweeds by bears has been noted only once, in Russia. We documented consumption of pondweed rhizomes by grizzly bears (Ursus arctos) in the Yellowstone region, 1977-96, during investigations of telemetry locations obtained from 175 radiomarked bears. We documented pondweed excav
Authors
D.J. Mattson, S.R. Podruzny, M.A. Haroldson
Changing patterns in coastal cutthroat trout (Oncorhynchus clarki clarki) diet and prey in a gradient of deciduous canopies
We examined the influence of riparian vegetation patterns on coastal cutthroat trout Oncorhynchus clarki clarki diet and prey from the summer of 2001 through the spring of 2002. Benthic and drifting invertebrates, allochthonous prey, and fish diet were collected from deciduous, conifer, and mixed sections of three Oregon coastal watersheds. The nine sites were best characterized as a continuum of
Authors
N. Romero, R. E. Gresswell, J.L. Li
A geostatistical approach for describing spatial pattern in stream networks
The shape and configuration of branched networks influence ecological patterns and processes. Recent investigations of network influences in riverine ecology stress the need to quantify spatial structure not only in a two-dimensional plane, but also in networks. An initial step in understanding data from stream networks is discerning non-random patterns along the network. On the other hand, data c
Authors
L.M. Ganio, C.E. Torgersen, R. E. Gresswell
American black bears and bee yard depredation at Okefenokee Swamp, Georgia
We studied American black bears (Ursus americanus), on the northwest periphery of Okefenokee Swamp in southeast Georgia, to assess landowner attitudes toward bears, estimate the extent of damage to commercial honey bee operations by bears, and evaluate methods to reduce bear depredations to apiaries. We collected 8,351 black bear radiolocations and identified 51 bee yards on our study area. Twenty
Authors
J. D. Clark, S. Dobey, D.V. Masters, B.K. Scheick, M.R. Pelton, M.E. Sunquist
Factors affecting settling, survival, and viability of black bears reintroduced to Felsenthal National Wildlife Refuge, Arkansas
We used radiotelemetry and population modeling techniques to examine factors related to population establishment of black bears (Ursus americanus) reintroduced to Felsenthal National Wildlife Refuge (NWR), Arkansas. Our objectives were to determine whether settling (i.e., establishment of a home range at or near the release site), survival, recruitment, and population viability were related to age
Authors
B.J. Wear, R. Eastridge, J. D. Clark
A simulation test of the effectiveness of several methods for error-checking non-invasive genetic data
Non-invasive genetic sampling (NGS) is becoming a popular tool for population estimation. However, multiple NGS studies have demonstrated that polymerase chain reaction (PCR) genotyping errors can bias demographic estimates. These errors can be detected by comprehensive data filters such as the multiple-tubes approach, but this approach is expensive and time consuming as it requires three to eight
Authors
David A. Roon, L.P. Waits, K.C. Kendall
Lack of significant changes in the herpetofauna of Theodore Roosevelt National Park, North Dakota, since the 1920s
We surveyed 88 upland wetlands and 12 1-km river sections for amphibians in Theodore Roosevelt National Park, North Dakota, during 2001–2002 to gather baseline data for future monitoring efforts and to evaluate changes in the distribution of species. We compared our results to collections of herpetofauna made during 1920–1922, 1954 and 1978–1979. The boreal chorus frog (Pseudacris maculata) was th
Authors
B. R. Hossack, P. S. Corn, D. S. Pilliod
Evaluating mixed samples as a source of error in non-invasive genetic studies using microsatellites
The use of noninvasive genetic sampling (NGS) for surveying wild populations is increasing rapidly. Currently, only a limited number of studies have evaluated potential biases associated with NGS. This paper evaluates the potential errors associated with analysing mixed samples drawn from multiple animals. Most NGS studies assume that mixed samples will be identified and removed during the genotyp
Authors
David A. Roon, M.E. Thomas, K.C. Kendall, L.P. Waits