SUPPORTING INFORMATION from Sea ice reduction drives genetic differentiation among Barents Sea polar bears

• Main Authors: Simo Njabulo Maduna, Jon Aars, Ida Fløystad, Cornelya F. C. Klütsch, Eve M. L. Zeyl Fiskebeck, Øystein Wiig, Dorothee Ehrich, Magnus Andersen, Lutz Bachmann, Andrew E. Derocher, Tommi Nyman, Hans Geir Eiken, Snorre B. Hagen
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: Genetics; Evolutionary Biology; arctic; climate change; genetic diversity; ice-dependent; sea ice loss; Ursus maritimus; Arctic; Svalbard; Barents Sea; Svalbard Archipelago; Norway; Climate change; Sea ice
• Online Access: https://doi.org/10.6084/m9.figshare.15656607.v1; https://figshare.com/articles/journal_contribution/SUPPORTING_INFORMATION_from_Sea_ice_reduction_drives_genetic_differentiation_among_Barents_Sea_polar_bears/15656607

Loss of Arctic sea ice due to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear ( Ursus maritimus ) sampled across two decades (1995–2016) from the Svalbard Archipelago, Norway, an area that is affected by rapid sea ice loss in the Arctic Barents Sea. We analysed genetic variation at 22 microsatellite loci for 626 polar bears from four sampling areas within the archipelago. Our results revealed a 3–10% loss of genetic diversity across the study period, accompanied by a near 200% in genetic differentiation across regions. These effects may best be explained by a decrease in gene flow caused by habitat fragmentation due to the loss of sea ice coverage, resulting in increased inbreeding of local polar bears within the focal sampling areas in the Svalbard Archipelago. This study illustrates the importance of genetic monitoring for developing adaptive management strategies for polar bears and other ice-dependent species.