Dietary ecology of Alaskan polar bears (Ursus maritimus) through time and in response to Arctic climate change
Dietary ecology of Alaskan polar bears (Ursus maritimus) through time and in response to Arctic climate change
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阿拉斯加北极熊（Ursus maritimus）随时间变化的饮食生态以及对北极气候变化的响应
DOI：
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发表时间：
2021
影响因子：
11.6
通讯作者：
L. Desantis
中科院分区：
文献类型：
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作者：
Ansley Petherick;Joshua D. Reuther;Scott Shirar;Shelby L Anderson;L. Desantis
北极气候变化对北极熊(Ursus Maritimus)构成严重威胁，因为海冰减少使海豹无法捕食，海洋生态系统进行自下而上的重组。与它们的姊妹物种灰熊(Ursus Arctos)相比，北极熊拉长的头骨和减少的磨牙牙齿是与在海冰上捕猎海豹和以鲸脂和肉类为食物的柔软、富含脂肪的食物有关的适应。随着海冰的显著减少，目前还不清楚北极熊是否以及如何改变了它们的饮食。弄清北极熊对气候变化的饮食反应，无论是现在还是过去，对这种顶级捕食者的适当保护和管理至关重要。当饮食策略可能不适应时，这一点尤其重要。在这里，我们测试了一种假设，即从牙齿微磨损质地分析推断的硬食物消费(即不太受欢迎的食物，包括骨头)随着北极变暖而增加。我们发现，随着时间的推移(包括大约1000年前)，北极熊在阿拉斯加表现出保守的没有硬物觅食，直到21世纪，与高度保守和专门的软脂和肉的饮食一致。值得注意的是，我们的结果还表明，一些21世纪的北极熊可能正在消耗更难的食物(例如，提高身体利用率，包括垃圾在内的陆地食物)，尽管它们的头骨和新陈代谢不适合这样的饮食。在21世纪之前，只有下颌较大的北极熊表现出更多的硬物进食，尽管程度远低于近亲灰熊，后者经常食用机械上具有挑战性的食物。北极熊在形态上是特殊的，它们的生物力学限制可能会限制它们消耗具有机械挑战性的饮食的能力，只有在最极端的情况下才会发生饮食变化。总体而言，北极熊高度专业化的饮食和头骨形态可能会严重限制它们适应北极变暖的能力。
Arctic climate change poses serious threats to polar bears (Ursus maritimus) as reduced sea ice makes seal prey inaccessible and marine ecosystems undergo bottom‐up reorganization. Polar bears’ elongated skulls and reduced molar dentition, as compared to their sister species the grizzly bear (Ursus arctos), are adaptations associated with hunting seals on sea ice and a soft, lipid‐rich diet of blubber and meat. With significant declines in sea ice, it is unclear if and how polar bears may be altering their diets. Clarifying polar bear dietary responses to changing climates, both today and in the past, is critical to proper conservation and management of this apex predator. This is particularly important when a dietary strategy may be maladaptive. Here, we test the hypothesis that hard‐food consumption (i.e., less preferred foods including bone), inferred from dental microwear texture analysis, increased with Arctic warming. We find that polar bears demonstrate a conserved absence of hard‐object feeding in Alaska through time (including approximately 1000 years ago), until the 21st century, consistent with a highly conserved and specialized diet of soft blubber and flesh. Notably, our results also suggest that some 21st‐century polar bears may be consuming harder foods (e.g., increased carcass utilization, terrestrial foods including garbage), despite having skulls and metabolisms poorly suited for such a diet. Prior to the 21st century, only polar bears with larger mandibles demonstrated increased hard‐object feeding, though to a much lower degree than closely related grizzly bears which regularly consume mechanically challenging foods. Polar bears, being morphologically specialized, have biomechanical constraints which may limit their ability to consume mechanically challenging diets, with dietary shifts occurring only under the most extreme scenarios. Collectively, the highly specialized diets and cranial morphology of polar bears may severely limit their ability to adapt to a warming Arctic.
北极气候变化推动整个西格陵兰景观的生态系统快速响应
影响因子：
6.7
作者：
Saros J
通讯作者：
Saros J