Publications
USGS research activities relevant to Alaska have yielded more than 9400 historical publications. This page features some of the most recent newsworthy research findings.
Filter Total Items: 3079
Interactions of brown bears, Ursus arctos, and gray wolves, Canis lupus, at Katmai National Park and Preserve, Alaska Interactions of brown bears, Ursus arctos, and gray wolves, Canis lupus, at Katmai National Park and Preserve, Alaska
We describe several encounters between Brown Bears (Ursus arctos) and Gray Wolves (Canis lupus) that were observed at Katmai National Park and Preserve in southwest Alaska. Katmai Brown Bears and Gray Wolves were observed interacting in a variety of behavioral modes that ranged from agonistic to tolerant. These observations provide additional insight regarding the behavioral plasticity...
Authors
Tom S. Smith, Steven T. Partridge, John W. Schoen
Ecological overview of Kenai Fjords National Park Ecological overview of Kenai Fjords National Park
The major drivers of Kenai Fjords ecosystems are tectonics and climate. In this overview, we describe how these forces have contributed to the shaping of the lands and ecosystems of Kenai Fjords. Physically, the park is comprised of several distinct components, set within a broader ecophysical framework that includes the Kenai Peninsula and coastal marine waters and islands. Squeezed...
Authors
Page Spencer, Gail V. Irvine
Reaction rim growth on olivine in silicic melts: Implications for magma mixing Reaction rim growth on olivine in silicic melts: Implications for magma mixing
Finely crystalline amphibole or pyroxene rims that form during reaction between silicic host melt and cognate olivine xenocrysts, newly introduced during magma mixing events, can provide information about the timing between mixing and volcanic eruptions. We investigated rim growth experimentally by placing forsteritic olivine in rhyolitic and rhyodacitic melts for times between 25 and...
Authors
Michelle L. Coombs, James E. Gardner
Sea otter research methods and tools Sea otter research methods and tools
Sea otters possess physical characteristics and life history attributes that provide both opportunity and constraint to their study. Because of their relatively limited diving ability they occur in nearshore marine habitats that are usually viewable from shore, allowing direct observation of most behaviors. Because sea otters live nearshore and forage on benthic invertebrates, foraging...
Authors
James L. Bodkin
Early environment and recruitment of black brant (Branta bernicla nigricans) into the breeding population Early environment and recruitment of black brant (Branta bernicla nigricans) into the breeding population
In geese, growth regulates survival in the first year. We examined whether early growth, which is primarily governed by environmental conditions, also affects the probability that individuals that survive their first year enter the breeding population. We used logistic regression on a sample of Black Brant (Branta bernicla nigricans) that were weighed at a known age in their first summer...
Authors
James S. Sedinger, Mark P. Herzog, David H. Ward
Detecting denning polar bears with Forward-Looking Infrared (FLIR) imagery Detecting denning polar bears with Forward-Looking Infrared (FLIR) imagery
Polar bears give birth in snow dens in midwinter and remain in dens until early spring. The survival and development of cubs is dependent on a stable environment within the maternal den. To mitigate potential disruption of polar bear denning by existing and proposed petroleum activities, we used forward-looking infrared (FLIR) viewing to try to detect heat rising from dens.We flew...
Authors
Steven C. Amstrup, G. York, T. L. McDonald, R. Nielson, Kristin S. Simac
Spatial and temporal multiyear sea ice distributions in the Arctic: A neural network analysis of SSM/I data, 1988-2001 Spatial and temporal multiyear sea ice distributions in the Arctic: A neural network analysis of SSM/I data, 1988-2001
Arctic multiyear sea ice concentration maps for January 1988-2001 were generated from SSM/I brightness temperatures (19H, 19V, and 37V) using modified multiple layer perceptron neural networks. Learning data for the neural networks were extracted from ice maps derived from Okean and ERS satellite imagery to capitalize on the stability of active radar multiyear ice signatures. Evaluations...
Authors
G. I. Belchansky, David C. Douglas, I.V. Alpatsky, Nikita G. Platonov
Spatial variation in shorebird nest success: Implications for inference Spatial variation in shorebird nest success: Implications for inference
Estimates of nest success are widely applied in order to evaluate a multitude of theoretical and practical issues. Frequently, however, researchers fail to limit their inferences to the appropriate spatial scale. We evaluated small-scale variation in nest success of Western Sandpipers Calidris mauri during a four-year study on the Yukon-Kuskokwim Delta in western Alaska. We use these...
Authors
Brian J. McCaffery, Daniel R. Ruthrauff
Recommendations for the use of mist nets for inventory and monitoring of bird populations Recommendations for the use of mist nets for inventory and monitoring of bird populations
We provide recommendations on the best practices for mist netting for the purposes of monitoring population parameters such as abundance and demography. Studies should be carefully thought out before nets are set up, to ensure that sampling design and estimated sample size will allow study objectives to be met. Station location, number of nets, type of nets, net placement, and schedule...
Authors
C. John Ralph, Erica H. Dunn, Will J. Peach, Colleen M. Handel
Alaska resource data file, Ruby quadrangle, Alaska Alaska resource data file, Ruby quadrangle, Alaska
No abstract available.
Authors
Cheryl E. Cameron, Garth E. Graham
Alaska resource data file: Tanana quadrangle Alaska resource data file: Tanana quadrangle
No abstract available.
Authors
David J. Szumigala, Garth E. Graham, Jennifer E. Athey
Estimating Dungeness crab (Cancer magister) abundance: Crab pots and dive transects compared Estimating Dungeness crab (Cancer magister) abundance: Crab pots and dive transects compared
Dungeness crabs (Cancer magister) were sampled with commercial pots and counted by scuba divers on benthic transects at eight sites near Glacier Bay, Alaska. Catch per unit of effort (CPUE) from pots was compared to the density estimates from dives to evaluate the bias and power of the two techniques. Yearly sampling was conducted in two seasons: April and September, from 1992 to 2000...
Authors
S. James Taggart, Charles E. O’Clair, Thomas C. Shirley, Jennifer Mondragon