Forecasting consequences of changing sea ice availability for Pacific walruses
Forecasting consequences of changing sea ice availability for Pacific walruses
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预测太平洋海象海冰可用性变化的后果
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
S. Noren
中科院分区：
文献类型：
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作者：
M. S. Udevitz;C. Jay;Rebecca L. Taylor;A. Fischbach;William S. Beatty;S. Noren
由于人类活动对环境的改变和干扰速度加快，因此更有必要预测环境变化对鱼类和野生动物种群的影响。将环境变化预测与行为反应和生物能量效应联系起来的模型可以为这些预测提供基础。人们特别感兴趣的是预测海冰可用性预计减少对太平洋海象（Odobenus rosmarus divergens）的影响。楚科奇海夏季海冰的减少导致太平洋海象增加了对沿海运输的使用，减少了对生产力更高的近海觅食区的使用。这种气候引起的分布和行为变化最终可能影响种群的状况。我们开发了行为模型，将海冰可用性的变化与成年雌海象的运动和活动水平联系起来，并调整了以前开发的生物能量学模型，将这些活动水平与能量需求和满足这些需求的能力联系起来。然后，我们将这些模型与未来冰可用性的大气循环模型预测相关联，以预测本世纪中后期雌性海象的秋季身体状况。我们的研究结果表明，随着楚科奇海的海冰变得越来越少，雌性海象将在该海域的西南部地区花费更多的时间，休息的时间更少，觅食的时间也更少。在未来的情景中，预测的秋季体重中位数比最近低7-12%，但后验分布广泛重叠，预测的季节性质量损失中位数（15-34%）与其他鳍足类经常经历的季节性质量损失相当。这些身体状况的季节性下降不太可能导致人口效应，但如果海象在白令海越冬时无法重建内源性储备，累积效应可能会对繁殖和生存产生影响，最终影响太平洋海象种群的状况。我们的方法提供了一个总体框架，预测广泛的环境变化和人为干扰的后果，可能会影响生物能量学通过行为反应或猎物的可用性变化。
The accelerating rate of anthropogenic alteration and disturbance of environments has increased the need for forecasting effects of environmental change on fish and wildlife populations. Models linking projections of environmental change with behavioral responses and bioenergetic effects can provide a basis for these forecasts. There is particular interest in forecasting effects of projected reductions in sea ice availability on Pacific walruses (Odobenus rosmarus divergens). Declining extent of summer sea ice in the Chukchi Sea has caused Pacific walruses to increase use of coastal haulouts and decrease use of more productive offshore feeding areas. Such climate-induced changes in distribution and behavior could ultimately affect the status of the population. We developed behavioral models to relate changes in sea ice availability to adult female walrus movements and activity levels, and adapted previously developed bioenergetics models to relate those activity levels to energy requirements and the ability to meet those requirements. We then linked these models to general circulation model projections of future ice availability to forecast autumn body condition for female walruses during mid- and late-century time periods. Our results suggest that as sea ice becomes less available in the Chukchi Sea, female walruses will spend more time in the southwestern region of that sea, less time resting, and less time foraging. Median forecasted autumn body masses were 7–12% lower in future scenarios than during recent times, but posterior distributions broadly overlapped and median forecasted seasonal mass losses (15–34%) were comparable to seasonal mass losses routinely experienced by other pinnipeds. These seasonal reductions in body condition would be unlikely to result in demographic effects, but if walruses were unable to rebuild endogenous reserves while wintering in the Bering Sea, cumulative effects could have implications for reproduction and survival, ultimately affecting the status of the Pacific walrus population. Our approach provides a general framework for forecasting consequences of the broad range of environmental changes and anthropogenic disturbances that may affect bioenergetics through behavioral responses or changes in prey availability.