Using satellite telemetry to define spatial population structure in polar bears in the Norwegian and western Russian Arctic

Abstract

Summary1. Animal populations, defined by geographical areas within a species' distribution where population dynamics are largely regulated by births and deaths rather than by migration from surrounding areas, may be the correct unit for wildlife management. However, in heterogeneous landscapes varying habitat quality may yield subpopulations with distinct patterns in resource use and demography significant to the dynamics of populations. 2. To define the spatial population structure of polar bears Ursus maritimus in the Norwegian and western Russian Arctic, and to assess the existence of a shared population between the two countries, we analysed satellite telemetry data obtained from 105 female polar bears over 12 years. 3. Using both cluster analyses and home-range estimation methods, we identified five population units inhabiting areas with different sea-ice characteristics and prey availability. 4. The continuous distribution of polar bear positions indicated that the different subpopulations formed one continuous polar bear population in the Norwegian and western Russian Arctic. Hence, Norway and Russia have a shared management responsibility. 5. The spatial population structure identified will provide a guide for evaluating geographical patterns in polar bear ecology, the dynamics of polar bear-seal relationships and the effects of habitat alteration due to climate change. The work illustrates the importance of defining population borders and subpopulation structure in understanding the dynamics and management of larger animals.

Site fidelity of Svalbard polar bears revealed by mark-recapture positions

“…Studies based on mark-recapture and telemetry have concluded that there may be some spatial overlap, but minor exchange of individuals, between the Barents Sea population and the East Greenland population to the west and the Kara Sea population to the east (Wiig 1995, Mauritzen et al 2002. The paucity of long displacements observed in this study supports the current evidence that exchange may occur between these populations, but only very rarely.…”

“…Large variation in annual home range size has been found in northern Canada, the Beaufort Sea and the Barents Sea (Wiig 1995, Ferguson et al 1999, Amstrup et al 2000, Mauritzen et al 2002. This seems to be strongly related to geographic differences in sea ice conditions and -variability (Ferguson et al 1999, Amstrup 2003.…”

Climate Change and the Molecular Ecology of Arctic Marine Mammals

“…Sea ice acts as both a substrate and a vehicle for travel and gene flow in polar bears, Ursus maritimus (Stirling and Derocher 1993, Patkeau et al 1995, Mauritzen et al 2002. Despite the long-distance movements that have been recorded for individual bears (e.g., Mauritzen et al 2002), analysis of variation within nuclear markers revealed restricted gene flow among several local populations of this species (Paetkau et al 1995(Paetkau et al , 1999 Table 2).…”

Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change

“…3), especially in areas of annual ice cover over the continental shelf and the inter-island channels of various archipelagos. They are distributed in approximately 19 different populations (Bethke et al 1996, Paetkau et al 1999, Lunn et al 2002, Mauritzen et al 2002, Amstrup et al 2004, Derocher 2005. Polar bears have annual movement patterns within individual home ranges.…”