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
Detecting grizzly bear use of ungulate carcasses using global positioning system telemetry and activity data
Global positioning system (GPS) wildlife collars have revolutionized wildlife research. Studies of predation by free-ranging carnivores have particularly benefited from the application of location clustering algorithms to determine when and where predation events occur. These studies have changed our understanding of large carnivore behavior, but the gains have concentrated on obligate carnivores.
Authors
Michael R. Ebinger, Mark A. Haroldson, Frank T. van Manen, Cecily M. Costello, Daniel D. Bjornlie, Daniel J. Thompson, Kerry A. Gunther, Jennifer K. Fortin, Justin E. Teisberg, Shannon R Pils, P J White, Steven L. Cain, Paul C. Cross
Estimating abundance in the presence of species uncertainty
1.N-mixture models have become a popular method for estimating abundance of free-ranging animals that are not marked or identified individually. These models have been used on count data for single species that can be identified with certainty. However, co-occurring species often look similar during one or more life stages, making it difficult to assign species for all recorded captures. This unc
Authors
Thierry A. Chambert, Blake R. Hossack, LeeAnn Fishback, Jon M. Davenport
Coherent late-Holocene climate-driven shifts in the structure of three Rocky Mountain lakes
Large-scale atmospheric pressure centers, such as the Aleutian and Icelandic Low, have a demonstrated relationship with physical lake characteristics in contemporary monitoring studies, but the responses to these phenomena are rarely observed in lake records. We observe coherent changes in the stratification patterns of three deep (>30 m) lakes inferred from fossil diatom assemblages as a response
Authors
Jeffery R. Stone, Jasmine E. Saros, Gregory T. Pederson
Does water chemistry limit the distribution of New Zealand mud snails in Redwood National Park?
New Zealand mud snails (NZMS) are exotic mollusks present in many waterways of the western United States. In 2009, NZMS were detected in Redwood Creek in Redwood National Park, CA. Although NZMS are noted for their ability to rapidly increase in abundance and colonize new areas, after more than 5 years in Redwood Creek, their distribution remains limited to a ca. 300 m reach. Recent literature sug
Authors
Ryan Vazquez, Darren M. Ward, Adam J. Sepulveda
Amphibian mortality events and ranavirus outbreaks in the Greater Yellowstone Ecosystem
Mortality events in wild amphibians go largely undocumented, and where events are detected, the numbers of dead amphibians observed are probably a small fraction of actual mortality (Green and Sherman 2001; Skerratt et al. 2007). Incidental observations from field surveys can, despite limitations, provide valuable information on the presence, host species, and spatial distribution of diseases. Her
Authors
Debra A. Patla, Sophia St-Hilaire, Andrew P. Rayburn, Blake R. Hossack, Charles R. Peterson
Risk and efficacy of human-enabled interspecific hybridization for climate-change adaptation: Response to Hamilton and Miller (2016)
Hamilton and Miller (2016) provide an interesting and provocative discussion of how hybridization and introgression can promote evolutionary potential in the face of climate change. They argue that hybridization—mating between individuals from genetically distinct populations—can alleviate inbreeding depression and promote adaptive introgression and evolutionary rescue. We agree that deliberate in
Authors
Ryan P. Kovach, Gordon Luikart, Winsor H. Lowe, Matthew C. Boyer, Clint C. Muhlfeld
Are brown trout replacing or displacing bull trout populations in a changing climate?
Understanding how climate change may facilitate species turnover is an important step in identifying potential conservation strategies. We used data from 33 sites in western Montana to quantify climate associations with native bull trout (Salvelinus confluentus) and non-native brown trout (Salmo trutta) abundance and population growth rates (λ). We estimated λ using exponential growth state space
Authors
Robert K. Al-Chokhachy, David A. Schmetterling, Chris Clancy, Pat Saffel, Ryan Kovach, Leslie Nyce, Brad Liermann, Wade A. Fredenberg, Ron Pierce
Plastic pikas: Behavioural flexibility in low-elevation pikas (Ochotona princeps)
Behaviour is an important mechanism for accommodating rapid environmental changes. Understanding a species’ capacity for behavioural plasticity is therefore a key, but understudied, aspect of developing tractable conservation and management plans under climate-change scenarios. Here, we quantified behavioural differences between American pikas (Ochotona princeps) living in an atypical, low-elevati
Authors
Johanna Varner, Joshua J. Horns, Mallory S. Lambert, Elizabeth Westberg, James Ruff, Katelyn Wolfenberger, Erik A. Beever, M. Denise Dearing
Climate variables explain neutral and adaptive variation within salmonid metapopulations: The importance of replication in landscape genetics
Understanding how environmental variation influences population genetic structure is important for conservation management because it can reveal how human stressors influence population connectivity, genetic diversity and persistence. We used riverscape genetics modelling to assess whether climatic and habitat variables were related to neutral and adaptive patterns of genetic differentiation (popu
Authors
Brian K. Hand, Clint C. Muhlfeld, Alisa A. Wade, Ryan Kovach, Diane C. Whited, Shawn R. Narum, Andrew P. Matala, Michael W. Ackerman, B. A. Garner, John S Kimball, Jack A. Stanford, Gordon Luikart
Density, distribution, and genetic structure of grizzly bears in the Cabinet-Yaak Ecosystem
The conservation status of the 2 threatened grizzly bear (Ursus arctos) populations in the Cabinet-Yaak Ecosystem (CYE) of northern Montana and Idaho had remained unchanged since designation in 1975; however, the current demographic status of these populations was uncertain. No rigorous data on population density and distribution or analysis of recent population genetic structure were available to
Authors
Katherine C. Kendall, Amy C. Macleod, Kristina L. Boyd, John Boulanger, J. Andrew Royle, Wayne F. Kasworm, David Paetkau, Michael F. Proctor, Tabitha A. Graves, Kim Annis
Ecological relevance of current water quality assessment unit designations in impaired rivers
Managers often nest sections of water bodies together into assessment units (AUs) to monitor and assess water quality criteria. Ideally, AUs represent an extent of waters with similar ecological, watershed, habitat and land-use conditions and no overlapping characteristics with other waters. In the United States, AUs are typically based on political or hydrologic boundaries rather than on ecologic
Authors
Megan J. Layhee, Adam J. Sepulveda, Andrew Ray, Greg Mladenka, Lynn Van Every
Salamander chytrid fungus (Batrachochytrium salamandrivorans) in the United States—Developing research, monitoring, and management strategies
The recently (2013) identified pathogenic chytrid fungus, Batrachochytrium salamandrivorans (Bsal), poses a severe threat to the distribution and abundance of salamanders within the United States and Europe. Development of a response strategy for the potential, and likely, invasion of Bsal into the United States is crucial to protect global salamander biodiversity. A formal working group, led by A
Authors
Evan H. Campbell Grant, Erin L. Muths, Rachel A. Katz, Stefano Canessa, M. J. Adams, Jennifer R. Ballard, Lee Berger, Cheryl J. Briggs, Jeremy T. H. Coleman, Matthew J. Gray, M. Camille Harris, Reid N. Harris, Blake R. Hossack, Kathryn P. Huyvaert, Jonathan E. Kolby, Karen R. Lips, Robert E. Lovich, Hamish I. McCallum, Joseph R. Mendelson, Priya Nanjappa, Deanna H. Olson, Jenny G. Powers, Katherine L. D. Richgels, Robin E. Russell, Benedikt R. Schmidt, Annemarieke Spitzen-van der Sluijs, Mary Kay Watry, Douglas C. Woodhams, C. LeAnn White