Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA.
Greenland Institute of Natural Resources, 3900 Nuuk, Greenland.
Science. 2022 Jun 17;376(6599):1333-1338. doi: 10.1126/science.abk2793. Epub 2022 Jun 16.
Polar bears are susceptible to climate warming because of their dependence on sea ice, which is declining rapidly. We present the first evidence for a genetically distinct and functionally isolated group of polar bears in Southeast Greenland. These bears occupy sea-ice conditions resembling those projected for the High Arctic in the late 21st century, with an annual ice-free period that is >100 days longer than the estimated fasting threshold for the species. Whereas polar bears in most of the Arctic depend on annual sea ice to catch seals, Southeast Greenland bears have a year-round hunting platform in the form of freshwater glacial mélange. This suggests that marine-terminating glaciers, although of limited availability, may serve as previously unrecognized climate refugia. Conservation of Southeast Greenland polar bears, which meet criteria for recognition as the world's 20th polar bear subpopulation, is necessary to preserve the genetic diversity and evolutionary potential of the species.
由于北极熊依赖于迅速减少的海冰，因此它们容易受到气候变化的影响。我们首次提供了格陵兰东南地区存在遗传上独特且功能上隔离的北极熊群体的证据。这些北极熊生活在类似于 21 世纪末北极地区高纬地区的海冰条件下，每年无冰期比物种估计的禁食阈值长超过 100 天。而在北极的大多数地区，北极熊依靠每年的海冰来捕捉海豹，而格陵兰东南地区的北极熊则全年都有淡水冰川混合物作为狩猎平台。这表明，虽然海洋终端冰川的供应有限，但它们可能成为以前未被识别的气候避难所。为了保护该物种的遗传多样性和进化潜力，有必要保护格陵兰东南地区的北极熊，这些北极熊符合被确认为世界第 20 个北极熊亚种群的标准。
