Spatial pattern of polar bears relative to reproductive status, habitat and prey distribution.
Education
Ph.D 2014 University of Wyoming, WY Zoology and Physiology
M.S. 1991 Frostburg State University, MD Wildlife Biology
B.S. 1983 East Sroudsburg State University, PA Biology/Environmental Studies
Professional Experience
1991 - Present Research Zoologist, USGS, Alaska Science Center, Anchorage, Alaska
Professional Activities and/or Memberships
Present:
The Wildlife Society
The Arctic Institute of North America
The IUCN Polar Bear Specialist Group
Pregnant polar bears enter maternity dens in October/November, give birth to cubs in December/January, and exit dens in March/April. Historically, most polar bears from the Southern Beaufort Sea (SBS) population constructed maternity dens on the sea ice. Over the last three decades, as sea ice has become thinner and prone to fragmentation, there has been a landward shift in the distribution...
Polar bears are tied to the sea ice for nearly all of their life cycle functions. Most important of these is foraging, or access to food. Polar bears almost exclusively eat seals, and they are equally as dependent upon the sea for their nutrition as are seals, whales, and other aquatic mammals. Polar bears are not aquatic, however, and their only access to the seals is from the surface of the...
Polar bears (Ursus maritimus) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and...
Animal structural body size and condition are often measured to evaluate individual health, identify responses to environmental change and food availability, and relate food availability to effects on reproduction and survival. A variety of condition metrics have been developed but relationships between these metrics and vital rates are rarely...
Rode, Karyn D.; Atwood, Todd C.; Thiemann, Gregory; St Martin, Michelle; Wilson, Ryan R.; Durner, George M.; Regehr, Eric V.; Talbot, Sandra L.; Sage, Kevin; Pagano, Anthony M.; Simac, Kristin S. Since the publication of this manuscript, readers have noted two errors in our analysis. The first is that we inadvertently stated that the forward looking infrared (FLIR) survey simulations only represented a single FLIR survey. In reality, the analysis assumed two independent FLIR surveys occurred prior to simulated seismic activity occurring...
Wilson, Ryan R.; Durner, George M.
This report presents data on the approximate locations and methods of discovery of 530 polar bear (Ursus maritimus) maternal dens observed in the Beaufort and Chukchi Seas and neighboring areas from 1910 to 2018, and archived partly by the U.S. Geological Survey, Alaska Science Center, and partly by the U.S. Fish and Wildlife Service, Marine...
Durner, George M.; Amstrup, Steven C.; Atwood, Todd C.; Douglas, David C.; Fischbach, Anthony S.; Olson, Jay W.; Rode, Karyn D.; Wilson, Ryan R. Large‐scale industrial activities can have negative effects on wildlife populations. Some of these effects, however, could be reduced with effective planning prior to development. The Coastal Plain of the Arctic National Wildlife Refuge, in northeastern Alaska, USA, is an important maternal denning area for polar bears (Ursus maritimus). Recent...
Wilson, Ryan R.; Durner, George M. Divergent movement strategies have enabled wildlife populations to adapt to environmental change. In recent decades, the Southern Beaufort Sea subpopulation of polar bears (Ursus maritimus) has developed a divergent movement strategy in response to diminishing sea ice where the majority of the subpopulation (73–85%) stays on the sea ice in summer...
Pagano, Anthony M.; Atwood, Todd C.; Durner, George M.; Williams, Terrie M. 1. Greenhouse gas-induced warming in the Arctic has caused declines in sea ice extent and changed its composition, raising concerns by all circumpolar nations for polar bear conservation. 2. Negative impacts have been observed in three well-studied polar bear subpopulations. Most subpopulations, however, receive little or no direct monitoring,...
Durner, George M.; Douglas, David C.; Atwood, Todd C. The analysis of animal tracking data provides important scientific understanding and discovery in ecology. Observations of animal trajectories using telemetry devices provide researchers with information about the way animals interact with their environment and each other. For many species, specific geographical features in the landscape can have...
Scharf, Henry R. ; Hooten, Mevin; Wilson, Ryan R. ; Durner, George M.; Atwood, Todd C. Climate change is altering the distribution of some wildlife species while warming temperatures are facilitating the northward expansion of pathogens, potentially increasing disease risk. Melting of Arctic sea ice is causing polar bears (Ursus maritimus) of the Southern Beaufort Sea (SBS) to increasingly spend summer on land, where they may...
Whiteman, John P.; Harlow, Henry J.; Durner, George M.; Regehr, Eric V.; Amstrup, Steven C.; Ben-David, Merav Plasticity in the physiological and behavioural responses of animals to prolonged food shortages may determine the persistence of species under climate warming. This is particularly applicable for species that can “adaptively fast” by conserving protein to protect organ function while catabolizing endogenous tissues. Some Ursids, including polar...
Whiteman, John P.; Harlow, Henry J.; Durner, George M.; Regher, Eric V; Amstrup, Steven C.; Ben-David, Merav
Polar bears (Ursus maritimus) in Alaska use the Arctic National Wildlife Refuge (ANWR) for maternal denning. Pregnant bears den in snow banks for more than 3 months in winter during which they give birth to and nurture young. Denning is one of the most vulnerable times in polar bear life history as the family group cannot simply walk away from a...
Durner, George M.; Atwood, Todd C. Regional declines in polar bear (Ursus maritimus) populations have been attributed to changing sea ice conditions, but with limited information on the causative mechanisms. By simultaneously measuring field metabolic rates, daily activity patterns, body condition, and foraging success of polar bears moving on the spring sea ice, we found that high...
Pagano, Anthony M.; Durner, George M.; Rode, Karyn D.; Atwood, Todd C.; Atkinson, Stephen N.; Peacock, Elizabeth; Costa, Daniel P.; Owen, Megan A.; Williams, Terrie M. Synchrony between reproduction and food availability is important in mammals due to the high energetic costs of gestation and lactation. Female polar bears (Ursus maritimus) must accumulate sufficient energy reserves during spring through autumn to produce and nurse cubs during the winter months in snow dens. Adequate time in a den is important to...
Rode, Karyn D.; Olson, Jay; Eggett, Dennis L.; Douglas, David C.; Durner, George M.; Atwood, Todd C.; Regehr, Eric V.; Wilson, Ryan R.; Smith, Tom; St. Martin, Michelle
A new study led by the U.S. Geological Survey and the University of Wyoming found that increased westward ice drift in the Beaufort and Chukchi seas requires polar bears to expend more energy walking eastward on a faster moving “treadmill” of sea ice.