## Breadcrumb

-  Publications 
-  Articles 

#           Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline      

      March 25, 2015    

In the southern Beaufort Sea of the United States and Canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (Ursus maritimus). Combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the U.S. Endangered Species Act. Here, we used mark–recapture models to investigate the population dynamics of polar bears in the southern Beaufort Sea from 2001 to 2010, years during which the spatial and temporal extent of summer sea ice generally declined. Low survival from 2004 through 2006 led to a 25–50% decline in abundance. We hypothesize that low survival during this period resulted from (1) unfavorable ice conditions that limited access to prey during multiple seasons; and possibly, (2) low prey abundance. For reasons that are not clear, survival of adults and cubs began to improve in 2007 and abundance was comparatively stable from 2008 to 2010, with ~900 bears in 2010 (90% CI 606–1212). However, survival of subadult bears declined throughout the entire period. Reduced spatial and temporal availability of sea ice is expected to increasingly force population dynamics of polar bears as the climate continues to warm. However, in the short term, our findings suggest that factors other than sea ice can influence survival. A refined understanding of the ecological mechanisms underlying polar bear population dynamics is necessary to improve projections of their future status and facilitate development of management strategies.

## Citation Information

## Related Content

                  -              Data           
                  -              Connect           

March 16, 2015

####                 U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010              

Alaska Science Center

#### Jeffrey Bromaghin, Ph.D.

##### Research Statistician

Alaska Science Center

jbromaghin@usgs.gov

907-786-7086

#### David Douglas

##### Research Wildlife Biologist

Alaska Science Center

ddouglas@usgs.gov

907-364-1576

####             George Durner, Ph.D. (Former Employee)          

##### Research Zoologist

Alaska Science Center

#### Todd Atwood, Ph.D.

##### Research Wildlife Biologist

Alaska Science Center

tatwood@usgs.gov

907-786-7093

## Related Content

March 16, 2015

####                 U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010              

Alaska Science Center

#### Jeffrey Bromaghin, Ph.D.

##### Research Statistician

Alaska Science Center

jbromaghin@usgs.gov

907-786-7086

#### David Douglas

##### Research Wildlife Biologist

Alaska Science Center

ddouglas@usgs.gov

907-364-1576

####             George Durner, Ph.D. (Former Employee)          

##### Research Zoologist

Alaska Science Center

#### Todd Atwood, Ph.D.

##### Research Wildlife Biologist

Alaska Science Center

tatwood@usgs.gov

907-786-7093

### Study Area

### Contact

####               Alaska Science Center          

4210 University DriveAnchorage, AK99508United States

(907) 786-7000

(907) 786-7020

### Explore Search

                  - canada
                  -  United States
                  - Beaufort Sea
                  - Alaska

View All **