Sea ice reduction drives genetic differentiation among Barents Sea polar bears

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 illustra...因气候变化导致的北极海冰消退，预计将降低依赖海冰物种的遗传多样性与基因流，并对其长期种群存续能力产生潜在负面影响。本研究以挪威斯瓦尔巴群岛（Svalbard Archipelago）为研究区域——该区域受北极巴伦支海快速海冰消退影响——对1995年至2016年这20年间采集的北极熊（Ursus maritimus）样本，探究了海冰覆盖减少对其产生的种群遗传学影响。我们对来自该群岛四个采样区域的626头北极熊的22个微卫星位点（microsatellite loci）的遗传变异展开了分析。研究结果显示，在整个研究周期内，种群遗传多样性损失了3%至10%，同时区域间的遗传分化程度提升了近200%。上述效应可通过海冰覆盖流失引发的生境破碎化导致基因流下降得到最佳解释，该过程使得斯瓦尔巴群岛重点采样区域内的本地北极熊近交程度加剧。本研究旨在阐释……