Substantial decline in polar bear range with sea ice loss

Polar bears rely heavily on sea ice to search for prey, and in Baffin Bay between Canada and Greenland, such ice-associated searching halts during ice-free months. However, since 1979, higher temperatures have resulted in the ice-free season in this region increasing by 12 days per decade in this region. Now, satellite-tags placed on 81 polar bears in Baffin Bay reveal that polar bears greatly reduced the area in which they forage between 1991-95 and 2009-15, by as much as 70% in summer. As a result, this subpopulation is becoming increasingly isolated from other nearby polar bear subpopulations. These results show the clear impacts of sea ice loss on polar bears now, with increasing impacts likely in the future. The research was led by SAFS professor and Applied Physics Lab researcher Kristin Laidre and her coauthors, and appears in the journal Ecology and Evolution.

Geographical range of Baffin Bay polar bears during the 1990s (mauve) and 2000s (green), showing the substantial decline, fragmentation, and isolation of this subpopulation from nearby polar bear groups.
Monthly changes in polar bear range, showing the especially pronounced decline in range during summer months from the 1990s (mauve) to 2000s (green).
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