Can polar bears use terrestrial foods to offset lost ice-based hunting opportunities?
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Full Publication: https://doi.org/10.1890/140202Product Type: Journal Article
Year: 2015
Authors: Rode, K. D., C. T. Robbins, L. Nelson, and S. C. Amstrup
Suggested Citation:
Rode, K. D., C. T. Robbins, L. Nelson, and S. C. Amstrup. 2015. Can polar bears use terrestrial foods to offset lost ice-based hunting opportunities?. Frontiers in Ecology and the Environment 13:138-145. doi:10.1890/140202
Abstract
Increased land use by polar bears (Ursus maritimus) due to climate-change-induced reduction of their sea-ice habitat illustrates the impact of climate change on species distributions and the difficulty of conserving a large, highly specialized carnivore in the face of this global threat. Some authors have suggested that terrestrial food consumption by polar bears will help them withstand sea-ice loss as they are forced to spend increasing amounts of time on land. Here, we evaluate the nutritional needs of polar bears as well as the physiological and environmental constraints that shape their use of terrestrial ecosystems. Only small numbers of polar bears have been documented consuming terrestrial foods even in modest quantities. Over much of the polar bear's range, limited terrestrial food availability supports only low densities of much smaller, resident brown bears (Ursus arctos), which use low-quality resources more efficiently and may compete with polar bears in these areas. Where consumption of terrestrial foods has been documented, polar bear body condition and survival rates have declined even as land use has increased. Thus far, observed consumption of terrestrial food by polar bears has been insufficient to offset lost ice-based hunting opportunities but can have ecological consequences for other species. Warming-induced loss of sea ice remains the primary threat faced by polar bears.
Keywords: Polar bears, climate change, sea ice, terrestrial foraging, body condition, survival
Annotation
Increased land use by polar bears (Ursus maritimus) due to climate-change-induced reduction of their sea-ice habitat illustrates the impact of climate change on species distributions and the difficulty of conserving a large, highly specialized carnivore in the face of this global threat. Only small numbers of polar bears have been documented consuming terrestrial foods even in modest quantities. Where consumption of terrestrial foods has been documented, polar bear body condition and survival rates have declined even as land use has increased. Thus far, observed consumption of terrestrial food by polar bears has been insufficient to offset lost ice-based hunting opportunities but can have ecological consequences for other species. Increased terrestrial use by polar bears also increases the potential for human-bear conflicts. Human activities such as oil development or construction taking place around potential terrestrial sources of food, such as bird colonies, should consider the elevated risk of polar bear encounters.