Climate-driven sympatry may not lead to foraging competition between congeneric top-predators
Date
2016-01-06
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Publisher
Nature Publishing Group
Abstract
Climate-driven sympatry may lead to competition for food resources between species. Rapid warming
in the West Antarctic Peninsula (WAP) is coincident with increasing gentoo penguin and decreasing
Adélie penguin populations, suggesting that competition for food may exacerbate the Adélie penguin
decline. On fine scales, we tested for foraging competition between these species during the chickrearing
period by comparing their foraging behaviors with the distribution of their prey, Antarctic
krill. We detected krill aggregations within the horizontal and vertical foraging ranges of Adélie and
gentoo penguins, and found that krill selected for habitats that balance the need to consume food
and avoid predation. In overlapping Adélie and gentoo penguin foraging areas, four gentoo penguins
switched foraging behavior by foraging at deeper depths, a strategy which limits competition with
Adélie penguins. This suggests that climate-driven sympatry does not necessarily result in competitive
exclusion of Adélie penguins by gentoo penguins. Contrary to a recent theory, which suggests that
increased competition for krill is one of the major drivers of Adélie penguin population declines, we
suggest that declines in Adélie penguins along the WAP are more likely due to direct and indirect climate
impacts on their life histories.
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Citation
Cimino, M. A. et al. Climate-driven sympatry may not lead to foraging competition between congeneric top-predators. Sci. Rep. 6, 18820; doi: 10.1038/srep18820 (2016).