Changes in average climatic conditions combined with the increasing frequency of unpredictable, extreme weather events may disrupt scientific predictions of the future penguin populations, according to a study published in PLOS ONE on January 29, 2014 by Amélie Lescroël from the Centre d'Ecologie Fonctionnelle et Evolutive (CNRS), France and colleagues.
Antarctic penguins are dependent year-round on sea ice as a foraging habitat, and survival depends on their ability to respond over both short- and long-term changes in sea ice. For 13 years, researchers collected data on the foraging ability of chick-rearing Adélie penguins on Ross Island, Antarctica. In the middle of their study, the breaking off of giant icebergs allowed them to determine how such extreme environmental events affect the sea-ice dependent penguins.
The authors suggest that penguins are able to respond to changes in sea ice concentrations under "normal" environmental conditions, but not as much in the face of extreme events, like the presence of giant icebergs. Under "normal" conditions, Adélie penguins were most successful at finding food at relatively low sea ice concentrations and should be able to cope with future reduction in summer sea ice concentration. By dramatically changing their immediate environment, giant icebergs reduced the penguins' access to prey and made them more inefficient overall. These results suggest that an increase in infrequent, extreme environmental events can disrupt the penguins' ability to respond to changes in the environment and can muddle scientific predictions normally based on past observations.
Amélie Lescroël added, "Our work shows that Adélie penguins could cope with less sea ice around their summer breeding grounds. However, we also showed that extreme environmental events, such as the calving of giant icebergs, can dramatically modify the relationship between Adélie penguins and sea ice. If the frequency of such extreme events increases, then it will become very hard to predict how penguin populations will buffer future sea ice changes."
Citation: Lescroël A, Ballard G, Grémillet D, Authier M, Ainley DG (2014) Antarctic Climate Change: Extreme Events Disrupt Plastic Phenotypic Response in Adélie Penguins. PLoS ONE 9(1): e85291. doi:10.1371/journal.pone.0085291
Financial Disclosure: Financial support was provided by NSF grants OPP 9526865, 9814882, 0125608, 0440643 and 0944411. DG is funded by CNRS and the French Polar Institut (IPEV) within the ADACLIM program (grant 388). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interest Statement: David G. Ainley is employed by a commercial company (H.T. Harvey & Associates) but the authors also maintain that no aspect of the submitted work has been/is in any way influenced by this affiliation. Additionally, this does not alter the authors' adherence to all PLOS ONE policies on sharing data and materials.
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