The ecology of polar bears in relation to sea ice dynamics
Seth Cherry, Ph.D. Candidate
My research focuses primarily on developing methods to assess and predict the effects of sea ice dynamics on polar bear populations. My thesis will examine various aspects of polar bear ecology in relation to seasonal and long-term changes in sea ice composition. I will focus on polar bears in 2 regions of Canada that are currently facing climate induced changes to sea-ice habitat: western Hudson Bay, Manitoba and the Beaufort Sea, Northwest Territories.

Deploying a GPS collar on an adult female polar bear in Western Hudson Bay

In western Hudson Bay, I am using GPS satellite collars to monitor polar bear movement patterns, habitat selection, and home ranges, as they relate to seasonal and yearly sea ice dynamics. The western Hudson Bay marine ecosystem experiences a high degree of natural intra-annual variation in sea ice composition and extent, which makes it an ideal location to study polar bear movement in relation to changing ice conditions. It is also home to one of the southernmost polar bear populations in the world, making it an opportune region to examine the longer-term effects of climate change on polar bear movement and habitat use. Climate change scenarios for western Hudson Bay forecast greater temperature increases than average global predictions which will likely result in extended ice-free periods and less consolidated winter sea ice. Monitoring how the western Hudson Bay bears respond to these changes will be important to future global polar bear conservation initiatives.
In the Beaufort Sea I am examining the use of blood biomarkers to assess the fasting physiology of polar bears. Blood samples collected during the mid 1980s will be used for comparison with samples collected during current research programs to determine if there have been changes in polar bear feeding patterns during time periods differing in environmental conditions. In addition, I will also be conducting research on the diet composition of polar bears in the Beaufort Sea using stable isotope analysis. In the past, dietary analyses for polar bears have relied on opportunistic observations and surveys of kill sites. However, polar bear habitat in the Beaufort Sea occurs in remote localities that are logistically difficult to access during most times of the year, making it hard to estimate dietary changes at a seasonal or inter-annual time scale. To overcome these difficulties I will be using stable carbon and nitrogen isotope analysis to help determine the feeding ecology of Beaufort Sea bears and develop strategies to monitor their future diet.

Collecting a shaving from the claw of a polar bear for stable isotope analysis

A polar bear on the sea-ice in the Beaufort Sea For more information on this research project please contact:Seth Cherry
University of Alberta
scherry@ualberta.ca
orAndrew Derocher
University of Alberta
derocher@ualberta.ca