Increased land use by Chukchi Sea polar bears in relation to changing sea ice conditions

PLoS ONE
By: , and 

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Abstract

Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986–1995 and 2008–2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Increased land use by Chukchi Sea polar bears in relation to changing sea ice conditions
Series title PLoS ONE
DOI 10.1371/journal.pone.0142213
Volume 10
Issue 11
Year Published 2015
Language English
Publisher PLOS
Contributing office(s) Alaska Science Center Biology MFEB
Description e0142213; 18 p.
Country United States
Other Geospatial Chukchi Sea
Online Only (Y/N) N
Additional Online Files (Y/N) N