How polar bearsTracking copewiththe the Polar Bear current climate changes Dr. Jon Aars, Norwegian Polar Institute

Jon Aars, Norwegian Polar Institute Illustration: Rasmus Hansson

Polar bear Black bear

Brown bear Polar bears are carnivores, and specialists on hunting ice associated seals

Bearded seal Ringed seal Erignathu s barbatus Phoca hispida Bears do not only eat seals climate

Sea ice

Ice associated seals Polar bears Importance of sea ice: ‐food ‐mating ‐travel between feeding, mating and denning areas Most mating occurs on sea ice

72% in Svalbard, Derocher et al. 2010 Marking of polar bears in Svalbard Platform for polar bear capture‐recapture work Glac ier fftronts ittimportant habitat (hunting ringed seal pups in spring) Getting data and samples Age determination Blood cell counts Studies of movement Different space use strategies Also large differences in swimming behavior

% time in water month Sea ice connects subpopulations from different areas

Greenland

Laptev Sea

Svalbard N. Kara Sea

Barent Sea

S. Kara Sea Norway Russia

Mauritzen et al. 2002 DD

All bears den on islands in the Svalbard area Late sea ice arrival at Hopen = few maternety dens

40 1996 s en

dd 30 LATE SEA ICE = FEW DENS

aternity 1995 20 1998 mm

2003 10 mber ofmber

uu 1997 1999 N 2001 2000 0 2002 2008 27 16 26 16 26 ct 6 ov ov 6 ec ec 5 O ov N N ec D D an 15 N D J n 25 Ja n 4 Ja eb 4 Date of arrival of 60% sea ice cover F b 1 Fe

Derocher et al., in revision Sea ice arrival at Hopen too late for adult females to get there and den in most recent years

1 Feb ee 1 Jan

0% sea ic 1 Dec 66

1 Nov Arrival of 1 Oct

1980 1985 1990 1995 2000 2005 2010 Year 60% sea ice days 1oct‐31dec

hopen

storfjorden

kongsøya

Nordaustlandet

kitøkvitøya Western Hudson Bay: earlier sea ice break up, lower survival of young and old bears

Regehr et al., J Wildl Managem, 2007 In Alaska, less and less bears den in multi year pack ice, and rather den on land

1985‐1994

1998‐2004

Reduction from 62% to 37% of observed maternity dens in multi year ice

Fischbach et al., polar biology, 2007 Survival and reproduction affected by increased period of ice free waters in Southern Beaufort Sea

2001–2003, the ice‐free period = mean 101 days (90‐119) female survival was high (0.96–0.99)

In 2004 and 2005, the ice‐free period = mean 135 days (134‐135) adult female survival was low (0.73–0.79).

Breeding rates and cub litter survival also declined with increasing duration of the ice‐free period

Regehr et al. Journal of Animal Ecology 2010, 79, 117–127