Landward and eastward shift of Alaskan polar bear denning associated with recent sea ice changes |
| |
Authors: | A S Fischbach S C Amstrup D C Douglas |
| |
Institution: | (1) USGS Alaska Science Center, 4230 University Drive, Anchorage, AK 99508, USA;(2) USGS Alaska Science Center, 1011 E Tudor Road, Anchorage, AK 99503, USA;(3) USGS Alaska Science Center, 3100 National Park Road, Juneau, AK 99801, USA |
| |
Abstract: | Polar bears (Ursus maritimus) in the northern Alaska region den in coastal areas and on offshore drifting ice. We evaluated changes in the distribution
of polar bear maternal dens between 1985 and 2005, using satellite telemetry. We determined the distribution of maternal dens
occupied by 89 satellite collared female polar bears between 137°W and 167°W longitude. The proportion of dens on pack ice
declined from 62% in 1985–1994 to 37% in 1998–2004 (P = 0.044) and among pack ice dens fewer occurred in the western Beaufort Sea after 1998. We evaluated whether hunting, attraction
to bowhead whale remains, or changes in sea ice could explain changes in den distribution. We concluded that denning distribution
changed in response to reductions in stable old ice, increases in unconsolidated ice, and lengthening of the melt season.
In consort, these changes have likely reduced the availability and quality of pack ice denning habitat. Further declines in
sea ice availability are predicted. Therefore, we expect the proportion of polar bears denning in coastal areas will continue
to increase, until such time as the autumn ice retreats far enough from shore that it precludes offshore pregnant females
from reaching the Alaska coast in advance of denning. |
| |
Keywords: | Alaska Beaufort Sea Denning Distribution Climate change Polar bear Satellite telemetry Sea ice Ursus maritimus |
本文献已被 SpringerLink 等数据库收录! |
|