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: 1300
Declines in body size of sockeye salmon associated with increased competition in the ocean Declines in body size of sockeye salmon associated with increased competition in the ocean
Declining body sizes have been documented for several species of Pacific salmon; however, whether size declines are caused mainly by ocean warming or other ecological factors, and whether they result primarily from trends in age at maturation or changing growth rates remain poorly understood. We quantified changes in mean body size and contributions from shifting size-at-age and age...
Authors
Jan Ohlberger, Timothy Joseph Cline, Daniel Schindler, Bert Lewis
Shrinking body size and climate warming: Many freshwater salmonids do not follow the rule Shrinking body size and climate warming: Many freshwater salmonids do not follow the rule
Declining body size is believed to be a universal response to climate warming and has been documented in numerous studies of marine and anadromous fishes. The Salmonidae are a family of coldwater fishes considered to be among the most sensitive species to climate warming; however, whether the shrinking body size response holds true for freshwater salmonids has yet to be examined at a...
Authors
Mary Solakas, Zachary S. Feiner, Robert Al-Chokhachy, Phaedra E. Budy, Tyrell DeWeber, Jouko Sarvala, Greg G. Sass, Scott A. Tolentino, Timothy E. Walsworth, Olaf P. Jensen
Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides
The acute decline in global biodiversity includes not only the loss of rare species, but also the rapid collapse of common species across many different taxa. The loss of pollinating insects is of particular concern because of the ecological and economic values these species provide. The western bumble bee (Bombus occidentalis) was once common in western North America, but this species...
Authors
William Michael Janousek, Margaret R. Douglas, Syd Cannings, Marion Clement, Casey Delphia, Jeffrey Everett, Richard G. Hatfield, Douglas A. Keinath, Jonathan B Koch, Lindsie M. McCabe, John Michael Mola, Jane Ogilvie, Imtiaz Rangwala, Leif L Richardson, Ashley T. Rohde, James P. Strange, Lusha M. Tronstad, Tabitha A. Graves
Redd superimposition mediates the accuracy, precision, and significance of redd counts for cutthroat trout Redd superimposition mediates the accuracy, precision, and significance of redd counts for cutthroat trout
Redd counts are commonly applied to estimate spawning population size for salmonids and allow for broad spatial and temporal coverage in monitoring efforts. However, the utility of redd counts may be compromised by observation error, particularly with respect to superimposition, where later arriving spawners construct redds overlapping existing redds. Here, we provide a mechanistic...
Authors
Jeffrey R. Baldock, Robert Al-Chokhachy, Timothy E. Walsworth, Annika W. Walters
Beyond presence mapping: Predicting fractional cover of non-native vegetation in Sentinel-2 imagery using an ensemble of MaxEnt models Beyond presence mapping: Predicting fractional cover of non-native vegetation in Sentinel-2 imagery using an ensemble of MaxEnt models
Non-native species maps are important tools for understanding and managing biological invasions. We demonstrate a novel approach to extend presence modeling to map fractional cover (FC) of non-native yellow sweet clover Melilotus officinalis in the Northern Great Plains, USA. We used ensembles of MaxEnt models to map FC across landscapes from satellite imagery trained from regional...
Authors
Todd M. Preston, Aaron N. Johnston, Kyle Gregory Ebenhoch, Robert H. Diehl
Enhancements to population monitoring of Yellowstone grizzly bears Enhancements to population monitoring of Yellowstone grizzly bears
In the Greater Yellowstone Ecosystem, counts of female grizzly bears (Ursus arctos) with cubs-of-the-year (females with cubs) from systematic aerial surveys and opportunistic ground sightings are combined with demographic data to derive annual population estimates. We addressed 2 limitations to the monitoring approach. As part of a rule set, a conservative distance of >30 km currently is...
Authors
Frank T. van Manen, Michael Ebinger, Cecily M. Costello, Daniel D. Bjornlie, Justin Clapp, Daniel Thompson, Mark A. Haroldson, Kevin L. Frey, Curtis Hendricks, Jeremy M. Nicholson, Kerry A. Gunther, Katharine R. Wilmot, Hilary Cooley, Jennifer Fortin-Noreus, Pat Hnilicka, Daniel B. Tyers
Wind-energy development alters pronghorn migration at multiple scales Wind-energy development alters pronghorn migration at multiple scales
Migration is a critical behavioral strategy necessary for population persistence and ecosystem functioning, but migration routes have been increasingly disrupted by anthropogenic activities, including energy development. Wind energy is the world's fastest growing source of electricity and represents an important alternative to hydrocarbon extraction, but its effects on migratory species...
Authors
Megan C. Milligan, Aaron N. Johnston, Jeffery L. Beck, Kaitlyn L. Taylor, Embere Hall, Lee Knox, Teal Cufaude, Cody F. Wallace, Geneva W. Chong, Matthew Kauffman
Insects in high-elevation streams: Life in extreme environments imperiled by climate change Insects in high-elevation streams: Life in extreme environments imperiled by climate change
Climate change is altering conditions in high-elevation streams worldwide, with largely unknown effects on resident communities of aquatic insects. Here, we review the challenges of climate change for high-elevation aquatic insects and how they may respond, focusing on current gaps in knowledge. Understanding current effects and predicting future impacts will depend on progress in three...
Authors
Jackson H. Birrell, Alisha A. Shah, Scott Hotaling, J. Joseph Giersch, Craig E. Williamson, Dean Jacobsen, H. Arthur Woods
Cryptic declines of small, cold-water specialists highlight potential vulnerabilities of headwater streams as climate refugia Cryptic declines of small, cold-water specialists highlight potential vulnerabilities of headwater streams as climate refugia
Increasing temperatures and climate-driven disturbances like wildfire are a growing threat to many species, including cold-water specialists. Montane areas and cold streams are often considered climate refugia that buffer communities against change. However, climate refugia are often species-specific, and despite growing awareness that life histories and habitat requirements shape...
Authors
Blake R. Hossack, Michael LeMoine, Emily Oja, Lisa A Eby
Genetic architecture and evolution of color variation in American black bears Genetic architecture and evolution of color variation in American black bears
Color variation is a frequent evolutionary substrate for camouflage in small mammals, but the underlying genetics and evolutionary forces that drive color variation in natural populations of large mammals are mostly unexplained. The American black bear, Ursus americanus (U. americanus), exhibits a range of colors including the cinnamon morph, which has a similar color to the brown bear...
Authors
E. Puckett, I. S. Davis, D. C. Harper, K. Wakamatsu, G. Battu, J. L. Belant, D. E. Beyer, C. Carpenter, A. P. Crupi, M. Davidson, C. S. DePerno, N. Forman, N. L. Fowler, D. L. Garshelis, N. Gould, K. Gunther, Mark A. Haroldson, S. Ito, David. M Kocka, C. Lackey, R. Leahy, C. Lee-Roney, T. Lewis, A. Lutto, K. McGowan, C. Olfenbuttel, M. Orlando, A. Platt, M. D. Pollard, M. Ramaker, Heather Reich, Jaime L. Sajecki, S. K. Sell, J. Strules, S. Thompson, Frank T. van Manen, Craig Whitman, R. Williamson, F. Winslow, C. B. Kaelin, M. S. Marks, G. S. Barsh
Tooth wear and the apparent consumption of human foods among American black bears (Ursus americanus) in Great Smoky Mountains National Park, USA Tooth wear and the apparent consumption of human foods among American black bears (Ursus americanus) in Great Smoky Mountains National Park, USA
Stable isotope analyses of hair have been used to estimate the consumption of human foods by American black bears (Ursus americanus). Consumption of human foods influences body mass and reproductive success of bears. However, the underlying factors that cause some bears to become conflict bears and resort to consuming human foods as a portion of their diet are not fully understood. We...
Authors
Kent A. Hatch, Kimberly A. Kester, Amanda Loveless, Beverly L. Roeder, Frank T. van Manen
Assessing the seasonal evolution of snow depth spatial variability and scaling in complex mountain terrain Assessing the seasonal evolution of snow depth spatial variability and scaling in complex mountain terrain
Dynamic natural processes govern snow distribution in mountainous environments throughout the world. Interactions between these different processes create spatially variable patterns of snow depth across a landscape. Variations in accumulation and redistribution occur at a variety of spatial scales, which are well established for moderate mountain terrain. However, spatial patterns of...
Authors
Zachary Miller, Erich Peitzsch, Eric A. Sproles, Karl W. Birkeland, Ross T. Palomaki