Adélie penguins colonization history and paleodiet trends document Holocene environmental changes in Victoria Land (Antarctica)

The identification of several abandoned penguin colonies on Victoria Land coastal areas and more than 200 radiocarbon dates provide a ≈7200-yr spanning Adélie penguin history (> 8000 yr BP considering calibrated dates). These data also supply information about Holocene environmental changes, especially regarding sea-ice extension. Between 5000 and 2500 years BP, Adélie Penguin colonies were more numerous than at present and those presently occupied were more extended (penguin optimum). Between 2300 and 1100 penguin population dramatically decreased in southern Scott Coast and in Terra Nova Bay; sea-ice extension and persistence were reduced due to warmer-than present condition in the Ross Sea. Paleodietary studies also contribute to better define the Holocene environmental picture. Due to ecological competition, variation of fish exploitation respect to krill in Adélie penguin diet seems to reflect sea-ice extension and persistence.