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: 1211
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
Incisor wear and age in Yellowstone bison
Biologists commonly use tooth eruption and wear patterns or cementum annuli techniques to estimate age of ungulates. However, in some situations the accuracy or sampling procedures of either approach are undesirable. We investigated the progression of several quantitative measures of wear with age, using permanent first incisors from Yellowstone bison (Bison bison), and tested for differences betw
Authors
D.A. Christianson, P.J.P. Gogan, K.M. Podruzny, E.M. Olexa
High dispersal in a frog species suggests that it is vulnerable to habitat fragmentation
Global losses of amphibian populations are a major conservation concern and their causes have generated substantial debate. Habitat fragmentation is considered one important cause of amphibian decline. However, if fragmentation is to be invoked as a mechanism of amphibian decline, it must first be established that dispersal is prevalent among contiguous amphibian populations using formal movement
Authors
W.C. Funk, A.E. Greene, P. S. Corn, F.W. Allendorf
Population structure of Columbia spotted frogs (Rana luteiventris) is strongly affected by the landscape
Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined gene
Authors
W.C. Funk, M.S. Blouin, P. S. Corn, B.A. Maxell, D. S. Pilliod, S. Amish, F.W. Allendorf
From the field: Brown bear habituation to people — Safety, risks, and benefits
Recently, brown bear (Ursus arctos) viewing has increased in coastal Alaska and British Columbia, as well as in interior areas such as Yellowstone National Park. Viewing is most often being done under conditions that offer acceptable safety to both people and bears. We analyze and comment on the underlying processes that lead brown bears to tolerate people at close range. Although habituation is a
Authors
Stephen Herrero, Tom Smith, Terry D. DeBruyn, Kerry Gunther, Colleen A. Matt
Bison PRNP genotyping and potential association with Brucella spp. seroprevalence
The implication that host cellular prion protein (PrPC) may function as a cell surface receptor and/or portal protein for Brucella abortus in mice prompted an evaluation of nucleotide and amino acid variation within exon 3 of the prion protein gene (PRNP) for six US bison populations. A non-synonymous single nucleotide polymorphism (T50C), resulting in the predicted amino acid replacement M17T (Me
Authors
C.M. Seabury, N.D. Halbert, P.J.P. Gogan, J.W. Templeton, J.N. Derr