Dr. Ian Stirling Canadian Wildlife Service, Environment Canada. Current Research: long-term change: polar bear, seal and arctic marine ecosystems

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1 Dr. Ian Stirling Canadian Wildlife Service, Environment Canada Current Research: long-term change: polar bear, seal and arctic marine ecosystems

2 Polar Bears, seals, and climate in Hudson Bay and the High Arctic Ian Stirling - Canadian Wildlife Service

3 Climate Change Will Have Profound Effects on Arctic Marine Ecosystems those species dependent on sea ice as their primary habitat will be particularly vulnerable to effects of a warming climate spatial and temporal changes in sea ice are expected to lead to shifts in trophic interactions

4 Why Use Polar Bears and seals to Monitor the Effects of Climate Change? they are at the top of the marine food chain

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16 Polar Basin Barrow A l a s k a Prudhoe Bay Kaktovik Aklavik Tuktoyaktuk Inuvik Paulatuk Sachs Harbour Holman Resolute Grise Fiord Arctic Bay Qaanaaq Pond Inlet Thule Savissivik Clyde Upernavik G r e e n l a n d Qeqertarsuaq Y u k o n Kugluktuk (Coppermine) Cambridge Bay Taloyoak Gjoa Haven Pelly Bay Igloolik Hall Beach Broughton Island Pangnirtung Nuuk B r i t i s h C o l u m b i a CANADIAN N o r t h w e s t A l b e r t a POLAR km Yellowknife T e r r i t o r i e s S a s k. Baker Lake Rankin Churchill Arviat M a n i t o b a Repulse Bay Chesterfield Inlet Inlet Whale Cove Fort Severn Cape Iqaluit Coral Dorset Harbour Lake Harbour Salluit Kangiqsujuaq Ivujivik Killiniq Quaqtaq Akulivik Tarpangajuq Kangirsuk Povungnituk Aupaluk Kangiqsualujjuaq Tasiujaq Nain Kuujjuak Hopedale Inukjuak Makkovik Winisk Attawapiskat O n t a r i o Sanikiluaq Kuujuarapik Chisasibi Q u é b e c L a b r a d o r N f l d. D. Cluff '96

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23 3500 Stirling and Øritsland (1995) 3000 Y = ( ) X B B1-4 HA1-8 B3-9 BB Number of polar bears HA4-5 WHB B5-9 B = Beaufort Strata BB = Baffin Bay HA = High Arctic Strata VMS = Viscount Melville Sound VMS WHB = Western Hudson Bay Number of seals x 10 5

24 Reproduction of seals and bears in relation to decadal scale fluctuations in ice conditions (Stirling 2002) HEAVY ICE WINTERS Ringed seals Proportion of young in harvest Ovulation rate ( Sachs Harbour, Holman) Natality Polar bears fewer bear cubs are born when seal reproduction is low 10 0 Density of ringed seals/100 km (late summer) Year

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26 Stirling and Kiliaan (1980)

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32 Churchill Maximum ice cover January - April James Bay Mid break-up late June 500 km Late break-up early August Early freeze-up mid November Stirling et al. (1977)

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36 Stirling et al. (1977)

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39 Trend in the Body Condition Index of Polar Bears in Western Hudson Bay, (Stirling et al. 1999; Lunn and Stirling unpublished data) Males Females with cubs ) 2 x Body Condi Three-year running means

40 Mean monthly surface air temperature increase per decade: April May Monthly temperatures in western Hudson Bay increased º C per decade; 1º C increase advances breakup by approximately one week Skinner et al. (1998) June

41 Timing of Break-up in Relation to Year, Western Hudson Bay, (Stirling et al. 1999; Lunn and Stirling unpublished data) 31 Jul 21 Jul 11 Jul 1 Jul 21 Jun Date of Sea Ice B 11 Jun 1 Jun Year r = , p = 0.001

42 65 N 95 W 90 W 85 W 80 W 75 W 70 W NUNAVUT QUEBEC 60 N 70 W 60 N 55 N 55 N MANITOBA Polar Bear movements Polar Bear Movements ONTARIO Kilometers 75 W 95 W 90 W 85 W 80 W

43 Trends in dates polar bears come ashore in Hudson Bay 23 Aug 13 Aug Aug DATE 24 Jul 14 Jul Jul 24 Jun Mean Ashore Date Date of Break-up 14 Jun YEAR Stirling et al. (1999)

44 Relationship between Date of Break-up and Body Condition Index of Polar Bears, Western Hudson Bay, (Stirling et al. 1999; Lunn and Stirling unpublished data) 0.8 males, r s = 0.479, p = ) 2 x Body Condi 8 Jun 22 Jun 6 Jul 20 Jul Date of Sea Ice Break-up females, r s = 0.541, p = 0.008

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46 Polar Bear Diets % Relative No. of Seals Beaufort Sea Nth Sth Western Hudson Bay Davis Strait Bearded seal Harbour seal Harp Seal Hooded Seal Ringed seal Walrus 0 Ringed Bearded Ringed Bearded Ringed Bearded Harbour Harp Walrus Ringed Bearded Harp Hooded Walrus (Iverson, Stirling, and Lang, in press)

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49 Western Hudson Bay Polar Bear Diets Relative No. of Seals ** ** WH Ice Breakup 94 - late (24 July) 95/ 96 - mid (14 July) 98 - early (24 June ** ** 0 Females Males Females Males Females Males Ringed Seals Bearded Seals Harbour Seals (Iverson, Stirling, and Lang, in press)

50 Trend in the Body Condition Index of Polar Bears in Western Hudson Bay, (Stirling et al. 1999; Lunn and Stirling unpublished data) Males Females with cubs ) 2 x Body Condi Three-year running means

51 Projected Temperature Change Between and Combined Effects of Projected Greenhouse Gas and Sulphate Aerosol Increases - Canadian Model

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59 Observed Decrease in Northern Hemisphere Sea Ice Extent 13.0 Sea Ice Extent (x 10 6 km 2 ) Bjorgo et al Chapman & Walsh 1993 Parkinson et al Ropelewski 1985 Zakharov (after Vinnikov et al. 1999, Science 286: )

60 Average minimum ice extent through 1980s, 1990s, and projection for 2050s (Comiso, 2002)

61 Arrival of sea ice and den abundance Quadratic regression, r 2 = Late arrival of sea ice _ few dens _ altered distribution Number NOV DEC Arrival date of 40-50% sea ice the previous autumn (Derocher et al. unpublished)

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67 ACKNOWLEDGEMENTS Principal Supporting Agencies Canadian Wildlife Service Churchill Northern Studies Centre Conservation Manitoba Dept. Biological Sciences, University of Alberta Northern Environmental Initiative Nunavut Wildlife Management Board NSERC Polar Continental Shelf Project World Wildlife Fund (Canada and International) Individuals for field and lab assistance D. Andriashek, Wendy Calvert, A.E. Derocher, N.J. Lunn, S. Miller, M.A. Ramsay, Cheryl Spencer, and many others for shorter periods over the years.

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70 Natality ( adult males, adult females Populatio with yo Three-year running means Year Proportion of yearlings caught alone Stirling et al (1999)

71 Mean April temperatures, warming events, and rain events at Winton Bay field camp and from weather stations in coastal areas of southeastern Baffin Island (Environment Canada). Weather Station Winton Bay Camp Brevoort Island Resolution Island Iqaluit Cape Dyer Years of recording weather data Dates of April rain events 9-11 April, April, April, April, April, 1979

72 Annual Surface Air Temperature Trends

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77 SEASONAL MOVEMENTS 2001/ Tag Date-15 Nov 15 Nov-15 Dec 15 Dec-15 May 15 May-Last Transmission

78 % of diet Diet Changes in WH Polar Bears * ** n = 200 ** ** 94/ 95 96/ bear sex: diet: Ringed Bearded Harbour Iverson et al. (unpublished)

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