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Journal Publications
Taylor D.M.K.,
Akeeagok S., Andriashek D., Barbour W, Born E.W.,
Calvert W., Cluff H.D., Ferguson S., Laake J., Rosing-Asvid A.,
Stirling I., and Messier F. 2001. Delineating Canadian and Greenland polar
bear (Ursus maritimus) populations by cluster analysis of movements.
Can. J. Zool. 79: 690–709 (PDF
= 1614 KB)
Abstract:
Within their circumpolar range,
polar bears (Ursus maritimus) are not subject to absolute barriers. However,
physiographic features do cause discontinuities in their movements. These
discontinuities in distribution can be used to delineate population units.
Based on satellite telemetry of the movements of female polar bears carried
out in 1989–1998, we used cluster analysis to identify 6 regions within the
Canadian and western Greenland Arctic in which movements appear to be
restricted enough to identify distinct populations. These regions generally
correspond to management units that have been previously identified as
Viscount Melville Sound, Lancaster Sound, Norwegian Bay, Kane Basin, Baffin
Bay, and Davis Strait. A north–south substructure 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 Inuit hunters. Only 2 of 65
bears that provided telemetry information for more than 1 year were
classified in different populations in different years. However, annual
rates of exchange, measured as the percentage of locations outside the
population boundary, ranged from 0.4 to 8.9%. Analysis of mark–recapture
movements indicated no difference enlarge-scale movements between the sexes
or long-term movements with age. Although our validation criteria for
demographic closure were satisfied, the observed rates of exchange between
adjacent populations suggest that population dynamics in adjacent
populations may not be completely independent. |
