Summer refugia of polar bears (Ursus maritimus) in the southern Beaufort Sea
- 390 Downloads
Climate change is altering habitats and causing changes to species behaviors and distributions. Rapid changes in Arctic sea ice ecosystems have increased the need to identify critical habitats for conservation and management of species such as polar bears (Ursus maritimus). We examined the distribution of adult female and subadult male and female polar bears tracked by satellite telemetry (n = 64 collars) in the southern Beaufort Sea, Canada, to identify summer refugia in 2007–2010. Using utilization distributions, we identified terrestrial and sea ice areas used as summer refugia when nearshore sea ice melted. Habitat use areas varied between months, but interannual variation was not significant. Overall, bears made high use of ice over shallow waters, and bears that remained near terrestrial areas used sea ice (presumably to hunt from) when it was available. The majority of the bears remained on sea ice during summer and used the edge of the pack ice most notably west of Banks Island, Canada. A mean of 27 % (range 22–33 %) of bears used terrestrial areas in Alaska and use was concentrated near the remains of subsistence harvested bowhead whales (Balaena mysticetus). Energetic expenditure is anticipated to increase as bears are required to travel further on a seasonal basis.
KeywordsPolar bear Ursus maritimus Beaufort Sea Distribution Sea ice Kernel density
We gratefully acknowledge support from ArcticNet, Canadian Association of Zoos and Aquariums, Canadian Circumpolar Institute’s Boreal Alberta Research, Canadian Wildlife Federation, Environment Canada, Hauser Bears, Inuvialuit Game Council, Natural Sciences and Engineering Research Council of Canada, Northwest Territories Department of Environment and Natural Resources—Inuvik Region, Polar Bears International, Polar Continental Shelf Project, Quark Expeditions Ltd., United States Department of the Interior (Bureau of Ocean Energy Management), and World Wildlife Fund (Canada and International). We furthermore thank Marie Auger-Méthé, Oliver Barker, Seth Cherry, Stephen Hamilton, Alysa McCall, Peter Molnár, Nick Pilfold, and Vicki Sahanatien for assistance in the field and pilot Mike Woodcock.
- Aagaard K (ed) (1984) The Beaufort Undercurrent. Academic Press, OrlandoGoogle Scholar
- Block WM, Brennan LA (1993) The habitat concept in ornithology: theory and applications. In: Power DM (ed) Current ornithology, vol 11. Plenum Press, New YorkGoogle Scholar
- Cooper PF (1974) Landfast ice in the southeastern part of the Beaufort Sea. In: Reed JC, Sater JE (eds) The coast and shelf of the Beaufort Sea. The Arctic Institute of North America, Arlington, pp 235–242Google Scholar
- Derocher AE, Garner GW, Lunn NJ, Wiig Ø (eds) (1998) Polar bears: proceedings of the twelfth working meeting of the IUCN/SSC polar bear specialist group. IUCN, Gland and CambridgeGoogle Scholar
- Hall LS, Krausman PR, Morrison ML (1997) The habitat concept and a plea for standard terminology. Wildl Soc B 25:173–182Google Scholar
- Stirling I, Lunn NJ (1997) Environmental fluctuations in Arctic marine ecosystems as reflected by variability in reproduction of polar bears and ringed seals. In: Woodin SJ, Marquiss M (eds) Ecology of Arctic environments. Blackwell Science, EdmontonGoogle Scholar