Dietary ecology of Alaskan polar bears ( Ursus maritimus ) through time and in response to Arctic climate change
| Autor: | Ansley Petherick, Joshua D. Reuther, Larisa R.G. DeSantis, Shelby L. Anderson, Scott Shirar |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
010504 meteorology & atmospheric sciences Ursus maritimus Climate Change Grizzly Bears Biology organization 010603 evolutionary biology 01 natural sciences biology.animal Blubber Sea ice Animals Environmental Chemistry Ice Cover 14. Life underwater Ursus Ecosystem 0105 earth and related environmental sciences General Environmental Science Apex predator Global and Planetary Change geography geography.geographical_feature_category Ecology Arctic Regions 15. Life on land biology.organism_classification organization.mascot Diet Arctic 13. Climate action Mammal Alaska Ursidae |
| Zdroj: | Global Change Biology. 27:3109-3119 |
| ISSN: | 1365-2486 1354-1013 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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