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Abandoned penguin colonies and environmental change in the Palmer Station area, Anvers Island, Antarctic Peninsula

Published online by Cambridge University Press:  07 May 2004

Steven D. Emslie
Affiliation:
Department of Biological Sciences, University of North Carolina, 601 South College Road, Wilmington, NC 28403, USA
William Fraser
Affiliation:
Polar Oceans Research Group, Department of Biology, Montana State University, Bozeman, MT 59717, USA
Raymond C. Smith
Affiliation:
Institute for Computational Earth System Science (ICESS), Department of Geography, University of California, Santa Barbara, CA 93106, USA
William Walker
Affiliation:
National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA. 7600 Sand Point Way NE, Seattle, WA 98115, USA

Abstract

Six abandoned colonies of Adélie penguin (Pygoscelis adeliae) were excavated near Palmer Station, Anvers Island, Antarctic Peninsula, to investigate the occupation history of this species. Sediments from each site yielded abundant fish bones and otoliths and squid beaks that represent prey remains deposited by penguins during the nesting period. Radiocarbon analyses indicate that colony occupation began prior to the Little Ice Age (LIA; 1500–1850 AD), with the oldest site dating to 644 yrs before present (BP; average reservoir-corrected date with Is range, 603–679 yr BP). Food remains indicate that the non-euphausiid prey of penguins consisted primarily of a mesopelagic squid (Psychroteuthis glacialis) and two species of fish (Pleuragramma antarcticun and Electrona antarctica). The relative abundance of the first two prey taxa varied significantly among six sites (X2>34.6; df = 10; P <0.001) with colonies dating prior to the LIA having greater representation of squid, and less of silverfish, than those occupied during the LIA. Data from control excavations at three modern colonies indicate a diet similar to that of the pre-LIA sites. These results suggest that Adélie penguins may have changed their diet in response to warming and cooling cycles in the past. In addition, only Adélie penguins are known to have nested in the Palmer Station area prior to the l950s; gentoo (Pygoscelis papua) and chinstrap (P. antarctica) penguins now breeding in this region have expanded their ranges southward in the Peninsula within the past 50 yrs, in correlation with pronounced regional warming.

Type
Earth Sciences
Copyright
© Antarctic Science Ltd 1998

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