Sea ice reduction drives genetic differentiation among Barents Sea polar bears ...

• Main Authors: Maduna, Simo Njabulo, Aars, Jon, Fløystad, Ida, Klutsch, Cornelya, Zeyl Fiskebeck, Eve, Wiig, Øystein, Ehrich, Dorothee, Andersen, Magnus, Bachmann, Lutz, Derocher, Andrew, Nyman, Tommi, Eiken, Hans Geir, Hagen, Snorre
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: FOS Biological sciences; Climate change; ice-dependent; Sea ice loss; Ursus maritimus; Arctic; Barents Sea; Nes; Nes’; Norway; Svalbard; Svalbard Archipelago; Tromsø; Norwegian Polar Institute; Sea ice
• Online Access: https://dx.doi.org/10.5061/dryad.zpc866t8x; https://datadryad.org/stash/dataset/doi:10.5061/dryad.zpc866t8x

Loss of Arctic sea ice due to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potential 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 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 ... : The Norwegian Polar Institute, Tromsø, Norway, collected the samples used in this study during a long-term project on the ecology of polar bears in the Barents Sea. To the best of our knowledge, the sampling protocol remained consistent across time. Polar bears were anesthetised from helicopters by remote injection of the drug Zoletil, and thereafter recovered. Tissue samples (biopsy samples and disks of skin from ear tagging) from these georeferenced bears (based on last sampling for bears captured several times) were frozen. We obtained samples from a total of 626 live captured individuals from the Svalbard Archipelago from 1995 to 2016. We allocated the 626 genotyped polar bears to the above mentioned four areas based on sampling locations: NWS (n = 123), NES (n = 110), SWS (n = 241), and SES (n = 152). We did not distinguish between coastal vs offshore bears based on movement data due to inevitable issues with sample sizes across spatiotemporal groups. Moreover, we included all available bears in our ...