Population Ecology

, Volume 47, Issue 3, pp 267–275 | Cite as

Population ecology of polar bears at Svalbard, Norway

Original Article


The population ecology of polar bears at Svalbard, Norway, was examined from 1988 to 2002 using live-captured animals. The mean age of both females and males increased over the study, litter production rate and natality declined and body length of adults decreased. Dynamics of body mass were suggestive of cyclical changes over time and variation in body mass of both adult females and adult males was related to the Arctic Oscillation index. Similarly, litter production rate and natality correlated with the Arctic Oscillation index. The changes in age-structure, reproductive rates and body length suggest that recovery from over-harvest continued for almost 30 years after harvest ended in 1973 and that density-dependent changes are perhaps being expressed in the population. However, the variation in reproduction and body mass in the population show a relationship between large-scale climatic variation and the upper trophic level in an Arctic marine ecosystem. Similar change in other polar bear populations has been attributed to climate change, and further research is needed to establish linkages between climate and the population ecology of polar bears.


  1. Aanes R, Sæther BE, Smith FM, Cooper EJ, Wookey PA, Øritsland NA (2002) The Arctic Oscillation predicts effects of climate change in two trophic levels in a high-arctic ecosystem. Ecol Lett 5:445–453CrossRefGoogle Scholar
  2. Ådlandsvik B, Loeng H (1991) A study of the climatic system in the Barents Sea. Polar Res 10:45–49Google Scholar
  3. AMAP (1998) AMAP assessment report: Arctic pollution issues. Arctic monitoring and assessment programme, OsloGoogle Scholar
  4. Amstrup SC, Durner GM (1995) Survival rates of radio-collared female polar bears and their dependent young. Can J Zool 73:1312–1322Google Scholar
  5. Amstrup SC, Stirling I, Lentfer JW (1986) Past and present status of polar bears in Alaska. Wildl Soc Bull 14:241–254Google Scholar
  6. Atkinson SN, Ramsay MA (1995) The effects of prolonged fasting of the body composition and reproductive success of female polar bears (Ursus maritimus). Funct Ecol 9:559–567Google Scholar
  7. Atkinson SN, Stirling I, Ramsay MA (1996) Growth in early life and relative body size among adult polar bears (Ursus maritimus). J Zool 239:225–234Google Scholar
  8. Barber DG, Iacozza J (2004) Historical analysis of sea ice conditions in M’Clintock Channel and the Gulf of Boothia, Nunavut: implications for ringed seal and polar bear habitat. Arctic 57:1–14Google Scholar
  9. Bernhoft A, Skaare JU, Wiig Ø, Derocher AE, Larsen HJS (2000) Possible immunotoxic effects of organochlorines in polar bears (Ursus maritimus) at Svalbard. J Toxicol Environ Health A 59:561–574CrossRefPubMedGoogle Scholar
  10. Bunnell FL, Tait DEN (1981) Population dynamics of bears—implications. In: Fowler CW, Smith TD (eds) Dynamics of large mammal populations. Wiley, New York, pp 75–98Google Scholar
  11. Bunnell FL, Tait DEN (1985) Mortality rates of North American bears. Arctic 38:316–323Google Scholar
  12. Calvert W, Ramsay MA (1998) Evaluation of age determination of polar bears by counts of cementum growth layer groups. Ursus 10:449–453Google Scholar
  13. Comiso JC (2002) A rapidly declining perennial sea ice cover in the Arctic. Geophys Res Lett 29:1956CrossRefGoogle Scholar
  14. Conway M (1906) No man’s land: a history of Spitsbergen from its discovery in 1596 to the beginning of the scientific exploration of the country. Cambridge University Press, CambridgeGoogle Scholar
  15. DeMaster DP, Stirling I (1981) Ursus maritimus. Mamm Spec 145:1–7Google Scholar
  16. Derocher AE (1999) Latitudinal variation in litter size of polar bears: ecology or methodology? Polar Biol 22:350–356CrossRefGoogle Scholar
  17. Derocher AE, Lunn NJ, Stirling I (2004) Polar bears in a warming climate. Integr Comp Biol 44:163–176Google Scholar
  18. Derocher AE, Stirling I (1992) The population dynamics of polar bears in western Hudson Bay. In: McCullough DR, Barrett RH (eds) Wildlife 2001: populations. Elsevier, London, pp 1150–1159Google Scholar
  19. Derocher AE, Stirling I (1994) Age-specific reproductive performance of female polar bears. J Zool 234:527–536Google Scholar
  20. Derocher AE, Stirling I (1995) Temporal variation in reproduction and body mass of polar bears in western Hudson Bay. Can J Zool 73:1657–1665Google Scholar
  21. Derocher AE, Stirling I (1996) Aspects of survival in juvenile polar bears. Can J Zool 74:1246–1252Google Scholar
  22. Derocher AE, Stirling I (1998) Maternal investment and factors affecting offspring size in polar bears (Ursus maritimus). J Zool 245:253–260CrossRefGoogle Scholar
  23. Derocher AE, Wiig Ø, Andersen M (2002) Diet composition of polar bears in Svalbard and the western Barents Sea. Polar Biol 25:448–452Google Scholar
  24. Derocher AE, Wiig Ø (2002) Postnatal growth in body length and mass of polar bears (Ursus maritimus) at Svalbard. J Zool 256:343–349CrossRefGoogle Scholar
  25. Derocher AE, Wolkers H, Colborn T, Schlabach M, Larsen TS, Wiig Ø (2003) Contaminants in Svalbard polar bear samples archived since 1967 and possible population level effects. Sci Total Environ 301:163–174Google Scholar
  26. Eberhardt LL (1977) Optimal policies for conservation of large mammals, with special reference to marine ecosystems. Biol Conserv 4:205–212Google Scholar
  27. Ferguson SH, Stirling I, McLoughlin P (2005) Climate change and ringed seal (Phoca hispida) recruitment in western Hudson Bay. Mar Mamm Sci 21:121–135Google Scholar
  28. Forchhammer MC, Post E (2004) Using large-scale climate indices in climate change ecology studies. Pop Ecol 46:1–12Google Scholar
  29. Forchhammer MC, Post E, Stenseth NC (1998) Breeding phenology and climate. Nature 391:29–30CrossRefPubMedGoogle Scholar
  30. Fowler CW (1990) Density dependence in northern fur seals (Callorhinus ursinus). Mar Mamm Sci 6:171–196Google Scholar
  31. Fraser D, Gardner JF, Kolenosky GB, Strathearn S (1982) Estimation of harvest rate of black bears from age and sex data. Wildl Soc Bull 10:53–57Google Scholar
  32. Hammill MO, Smith TG (1991) The role of predation in the ecology of the ringed seal in Barrow Strait, Northwest Territories, Canada. Mar Mamm Sci 7:123–135Google Scholar
  33. Henriksen EO, Derocher AE, Gabrielsen GW, Skaare JU, Wiig Ø (2001) Monitoring PCBs in polar bears: lessons learned from recent data. J Environ Monit 3:493–498CrossRefPubMedGoogle Scholar
  34. Kingsley MCS (1979) Fitting the von Bertalanffy growth equation to polar bear age-weight data. Can J Zool 57:1020–1025Google Scholar
  35. Kingsley MCS, Nagy JA, Reynolds HV (1988) Growth in length and weight of northern brown bears: differences between sexes and populations. Can J Zool 66:981–986Google Scholar
  36. Larsen T (1985) Polar bear denning and cub production in Svalbard, Norway. J Wildl Manage 49:320–326Google Scholar
  37. Larsen T (1986) Population biology of the polar bear (Ursus maritimus) in the Svalbard area. Norsk Polarinst Skr 184:1–55Google Scholar
  38. Leberg PL, Smith MH (1993) Influence of density on growth of white-tailed deer. J Mamm 74:723–731Google Scholar
  39. Lee J, Taylor M (1994) Aspects of the polar bear harvest in the Northwest Territories, Canada. Int Conf Bear Biol Manag 9:237–243Google Scholar
  40. Lie E, Larsen HJS, Larsen S, Johansen GM, Borgen T, Derocher AE, Lunn NJ, Norstrom RJ, Wiig Ø, Skaare JU (2003) Does high OC exposure impair the resistance to infection in polar bears (Ursus maritimus)? Part I: effect of OC on the humoral immunity. J Toxicol Environ Health A 67:555–582Google Scholar
  41. Liu J, Curry JA, Hu Y (2004) Recent Arctic sea ice variability: connections to the Arctic Oscillation and the ENSO. Geophys Res Lett 31:L09211CrossRefGoogle Scholar
  42. Lønø O (1970) The polar bear (Ursus maritimus Phipps) in the Svalbard area. Norsk Polarinst Skr 149:1–115Google Scholar
  43. Mauritzen M, Derocher AE, Wiig Ø (2001) Space-use strategies of female polar bears in a dynamic sea ice habitat. Can J Zool 79:1704–1713CrossRefGoogle Scholar
  44. Mauritzen M, Derocher AE, Wiig Ø, Belikov SE, Boltunov A, Hansen E, Garner GW (2002) Using satellite telemetry to define spatial population structure in polar bears in the Norwegian and western Russian Arctic. J Appl Ecol 39:79–90CrossRefGoogle Scholar
  45. Norstrom RJ, Belikov SE, Born EW, Garner GW, Malone B, Olpinski S, Ramsay MA, Schliebe S, Stirling I, Stishov MS, Taylor MK, Wiig Ø (1998) Chlorinated hydrocarbon contaminants in polar bears from eastern Russia, North America, Greenland and Svalbard. Arch Environ Contam Toxicol 35:354–367CrossRefPubMedGoogle Scholar
  46. Ottersen G, Stenseth NC (2001) Atlantic climate governs oceanographic and ecological variability in the Barents Sea. Limnol Ocean 46:1774–1780Google Scholar
  47. Paetkau D, Amstrup SC, Born EW, Calvert W, Derocher AE, Garner GW, Messier F, Stirling I, Taylor M, Wiig Ø, Strobeck C (1999) Genetic structure of the world’s polar bear populations. Mol Ecol 8:1571–1585CrossRefPubMedGoogle Scholar
  48. Paloheimo JE, Fraser D (1981) Estimation of harvest rate and vulnerability from age and sex data. J Wildl Manag 45:948–958Google Scholar
  49. Parkinson CL (2000) Variability of Arctic sea ice: the view from space, an 18-year record. Arctic 53:341–358Google Scholar
  50. Post E, Forchhammer MC (2002) Synchronization of animal population dynamics by large-scale climate. Nature 420:168–171CrossRefPubMedGoogle Scholar
  51. Prestrud P, Stirling I (1994) The International Polar Bear Agreement and the current status of polar bear conservation. Aquat Mamm 20.3:113–124Google Scholar
  52. Ralls K, Harvey PH (1985) Geographic variation in size and sexual dimorphism of North American weasels. Biol J Linn Soc 25:119–167Google Scholar
  53. Ramsay MA, Stirling I (1988) Reproductive biology and ecology of female polar bears (Ursus maritimus). J Zool 214:601–634Google Scholar
  54. SAS Institute (1989) SAS/STAT User’s guide, ver. 6, 4th edn. SAS Institute, Cary, N.C.Google Scholar
  55. Shapiro I, Colony R, Vinje T (2003) April sea ice extent in the Barents Sea, 1850–2001. Polar Res 22:5–10Google Scholar
  56. Skaare JU, Bernhoft A, Derocher A, Gabrielsen GW, Goksøyr A, Henriksen E, Larsen HJ, Lie E, Wiig Ø (1999) Organochlorines in top predators at Svalbard—occurrence, levels and effects. Toxicol Lett 112:103–109CrossRefGoogle Scholar
  57. Stirling I (2002) Polar bears and seals in the eastern Beaufort Sea and Amundsen Gulf: a synthesis of population trends and ecological relationships over three decades. Arctic 55:59–76Google Scholar
  58. Stirling I, Calvert W, Andriashek D (1980) Population ecology studies of the polar bear in the area of southeastern Baffin Island. Can Wildl Serv Occ Pap 44:1–31Google Scholar
  59. Stirling I, Derocher AE (1993) Possible impacts of climatic warming on polar bears. Arctic 46:240–245Google Scholar
  60. Stirling I, Kingsley M, Calvert W (1982) The distribution and abundance of seals in the eastern Beaufort Sea, 1974–1979. Can Wildl Serv Occ Pap 47:1–25Google Scholar
  61. Stirling I, Lunn NJ, Iacozza J (1999) Long-term trends in the population ecology of polar bears in western Hudson Bay in relation to climate change. Arctic 52:294–306Google Scholar
  62. Stirling I, Spencer C, Andriashek D (1989) Immobilization of polar bears (Ursus maritimus) with Telazol in the Canadian Arctic. J Wildl Dis 25:159–168PubMedGoogle Scholar
  63. Taylor MK, DeMaster DP, Bunnell FL, Schweinsburg RE (1987) Modeling the sustainable harvest of female polar bears. J Wildl Manag 51:811–820Google Scholar
  64. Thompson DWJ, Wallace JM (1998) The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophy Res Lett 25:1297–1300CrossRefGoogle Scholar
  65. Tremblay LB (2001) Can we consider the Arctic Oscillation independently from the Barents Oscillation? Geophys Res Lett 28:4227–4330CrossRefGoogle Scholar
  66. Vibe C (1967) Arctic animals in relation to climatic fluctuations. Meddelelser om Grønland 170:1–227Google Scholar
  67. Watts PD, Hansen SE (1987) Cyclic starvation as a reproductive strategy in the polar bear. Symp Zool Soc Lond 57:305–318Google Scholar
  68. Wiig Ø (1995) Distribution of polar bears (Ursus maritimus) in the Svalbard area. J Zool 237:515–529Google Scholar
  69. Wiig Ø (1998) Survival and reproductive rates for polar bears at Svalbard. Ursus 10:25–32Google Scholar

Copyright information

© The Society of Population Ecology and Springer-Verlag Tokyo 2005

Authors and Affiliations

  1. 1.Department of Biological SciencesUniversity of AlbertaEdmontonCanada
  2. 2.Norwegian Polar InstituteTromsøNorway

Personalised recommendations