Proliferation of East Antarctic Adélie penguins in response to historical deglaciation

• Published in: BMC Evolutionary Biology
• Main Authors: Younger, Jane, Emmerson, Louise, Southwell, Colin, Lelliott, Patrick, Miller, Karen
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: climate change ecology; Bayesian skyline plot; palaeoecology; Holocene; molecular ecology; seabirds; Pygoscelis adeliae; last glacial maximum; demography; Antarc*; Antarctic; Antarctic Peninsula; Antarctica; East Antarctica; Sea ice; Southern Ocean
• Online Access: https://researchers.mq.edu.au/en/publications/aaeb2767-1bbc-4e78-bea0-714e2fd5b411; https://doi.org/10.1186/s12862-015-0502-2; https://research-management.mq.edu.au/ws/files/16798645/mq-41803-Publisher%20version%20(open%20access).pdf; http://www.scopus.com/inward/record.url?scp=84946944562&partnerID=8YFLogxK

Background: Major, long-term environmental changes are projected in the Southern Ocean and these are likely to have impacts for marine predators such as the Adélie penguin (Pygoscelis adeliae). Decadal monitoring studies have provided insight into the short-term environmental sensitivities of Adélie penguin populations, particularly to sea ice changes. However, given the long-term nature of projected climate change, it is also prudent to consider the responses of populations to environmental change over longer time scales. We investigated the population trajectory of Adélie penguins during the last glacial-interglacial transition to determine how the species was affected by climate warming over millennia. We focussed our study on East Antarctica, which is home to 30 % of the global population of Adélie penguins. Methods: Using mitochondrial DNA from extant colonies, we reconstructed the population trend of Adélie penguins in East Antarctica over the past 22,000 years using an extended Bayesian skyline plot method. To determine the relationship of East Antarctic Adélie penguins with populations elsewhere in Antarctica we constructed a phylogeny using mitochondrial DNA sequences. Results: We found that the Adélie penguin population expanded 135-fold from approximately 14,000 years ago. The population growth was coincident with deglaciation in East Antarctica and, therefore, an increase in ice-free ground suitable for Adélie penguin nesting. Our phylogenetic analysis indicated that East Antarctic Adélie penguins share a common ancestor with Adélie penguins from the Antarctic Peninsula and Scotia Arc, with an estimated age of 29,000 years ago, in the midst of the last glacial period. This finding suggests that extant colonies in East Antarctica, the Scotia Arc and the Antarctic Peninsula were founded from a single glacial refuge. Conclusions: While changes in sea ice conditions are a critical driver of Adélie penguin population success over decadal and yearly timescales, deglaciation appears to have been the key ...