Delineating Canadian and Greenland polar bear (Ursus maritimus) populations by cluster analysis of movements

Within their circumpolar range, polar bears (Ursus maritimus) are not subje ct to absolute barriers. However, physiographic features do cause discontin uities in their movements. These discontinuities in distribution can be use d to delineate population units. Based on satellite telemetry of the moveme nts of female polar bears carried out in 1989-1998, we used cluster analysi s to identify 6 regions within the Canadian and western Greenland Arctic in which movements appear to be restricted enough to identify distinct popula tions. These regions generally correspond to management units that have bee n previously identified as Viscount Melville Sound, Lancaster Sound, Norweg ian Bay, Kane Basin, Baffin Bay, and Davis Strait. A north-south substructu re was identified for the Baffin Bay population, but it was weaker than the structure identified for the 6 primary units. The 6 units were consistent with genetic information, except for the Baffin Bay - Kane Basin separation , and with mark-recapture observations and the traditional knowledge of Inu it hunters. Only 2 of 65 bears that provided telemetry information for more than 1 year were classified in different populations in different years. H owever, annual rates of exchange, measured as the percentage of locations o utside the population boundary, ranged from 0.4 to 8.9%. Analysis of mark-r ecapture movements indicated no difference in large-scale movements between the sexes or long-term movements with age. Although our validation criteri a for demographic closure were satisfied, the observed rates of exchange be tween adjacent populations suggest that population dynamics in adjacent pop ulations may not be completely independent.