Adaptive long-term fasting in land and ice-bound polar bears: Coping with ice loss in the Arctic

The population biology of polar bears occupying land in summer months is comparatively well known. Much less is known about the larger fraction of polar bear populations which stays on the ice through the summer. A better understanding of the physiology of fasting in both summer habitats is needed to understand how reduced sea ice cover in the Arctic will impact polar bear populations. Bears that stay ashore in summer have almost no access to food and tend to be inactive. Those that stay on the ice, however, have continued access to prey and make extensive movements. This project pairs scientists from the University of Wyoming and the U. S. Geological Service to follow the movements of bears in both habitats and monitor their body temperature, muscle condition, blood chemistry, and metabolism. They will determine the physiological implications of summering on the ice versus on shore. The physiological data will be added to spatially-explicit individual-based population models to predict population response to reduced ice cover. The results will provide information important to management by indigenous, U.S., and international management and conservation agencies and address the interests of policy makers and the public. Funding Program: Arctic Natural Sciences (ANS) Sponsor: University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071-2000

夏季栖息于陆地的北极熊种群生物学特征相对为人熟知。相较之下，夏季仍滞留海冰之上的北极熊种群占比更高，相关研究却少得多。要理解北极海冰缩减将如何影响北极熊种群，亟需进一步厘清两类夏季生境下北极熊的禁食生理机制。夏季登陆的北极熊几乎无法获取食物，通常处于活动量极低的状态；而滞留海冰的个体仍可持续捕猎，并进行长距离移动。本项目由怀俄明大学（University of Wyoming）与美国地质调查局（U. S. Geological Service）的科研人员合作开展，将追踪两类生境中北极熊的活动轨迹，并监测其体温、肌肉状态、血液生化指标与代谢水平。研究团队将明确夏季滞留海冰与登陆陆地分别会带来哪些生理层面的影响。相关生理数据将被纳入空间显式个体基种群模型（spatially-explicit individual-based population models），以预测海冰缩减对种群的影响。研究结果将为原住民、美国及国际管理与保护机构的管理工作提供重要参考，同时回应政策制定者与公众的关切。资助项目：北极自然科学计划（Arctic Natural Sciences, ANS） 资助方：怀俄明大学，地址：美国怀俄明州拉勒米市东大学大道1000号，邮编82071-2000