title: Rapid Environmental Change Drives Increased Land Use by an Arctic Marine Predator.
abstract: In the Arctic Ocean's southern Beaufort Sea (SB), the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall) has increased substantially since the late 1990s. Historically, polar bears (Ursus maritimus) of the SB have mostly remained on the sea ice year-round (except for those that came ashore to den), but recent changes in the extent and phenology of sea ice habitat have coincided with evidence that use of terrestrial habitat is increasing. We characterized the spatial behavior of polar bears spending summer and fall on land along Alaska's north coast to better understand the nexus between rapid environmental change and increased use of terrestrial habitat. We found that the percentage of radiocollared adult females from the SB subpopulation coming ashore has tripled over 15 years. Moreover, we detected trends of earlier arrival on shore, increased length of stay, and later departure back to sea ice, all of which were related to declines in the availability of sea ice habitat over the continental shelf and changes to sea ice phenology. Since the late 1990s, the mean duration of the open-water season in the SB increased by 36 days, and the mean length of stay on shore increased by 31 days. While on shore, the distribution of polar bears was influenced by the availability of scavenge subsidies in the form of subsistence-harvested bowhead whale (Balaena mysticetus) remains aggregated at sites along the coast. The declining spatio-temporal availability of sea ice habitat and increased availability of human-provisioned resources are likely to result in increased use of land. Increased residency on land is cause for concern given that, while there, bears may be exposed to a greater array of risk factors including those associated with increased human activities.
authors.affiliation: U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, 99508, United States of America.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Atwood
authors.affiliation: U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, 99508, United States of America.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Peacock
authors.affiliation: University of Connecticut, Center for Environmental Sciences and Engineering and Department of Natural Resources and the Environment, 1376 Storrs Road, Storrs, CT, 06269, United States of America.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: McKinney
authors.affiliation: Utah State University, Department of Wildland Resources, Logan, UT, 84322-5230, United States of America.
authors.forename: Kate
authors.initials: K
authors.lastname: Lillie
authors.affiliation: U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 E Tudor Road, Anchorage, AK, 99503, United States of America.
authors.forename: Ryan
authors.initials: R
authors.lastname: Wilson
authors.affiliation: U.S. Geological Survey, Alaska Science Center, 250 Egan Drive, Juneau, AK, 99801, United States of America.
authors.forename: David C
authors.initials: DC
authors.lastname: Douglas
authors.affiliation: U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 E Tudor Road, Anchorage, AK, 99503, United States of America.
authors.forename: Susanne
authors.initials: S
authors.lastname: Miller
authors.affiliation: Utah State University, Department of Wildland Resources, Logan, UT, 84322-5230, United States of America.
authors.forename: Pat
authors.initials: P
authors.lastname: Terletzky
mesh_terms: D000818:Animals; D001110:Arctic Regions; D057231:Climate Change; D046448:Ice Cover; D008386:Marine Biology; D011235:Predatory Behavior; D001503:Ursidae / Q000502:physiology*