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Antarctic Science

Table of Contents - 1998 - Volume 10, Issue 03  


Earth Sciences

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

Steven D. Emslie a1, William Fraser a2, Raymond C. Smith a3 and William Walker a4
a1 Department of Biological Sciences, University of North Carolina, 601 South College Road, Wilmington, NC 28403, USA
a2 Polar Oceans Research Group, Department of Biology, Montana State University, Bozeman, MT 59717, USA
a3 Institute for Computational Earth System Science (ICESS), Department of Geography, University of California, Santa Barbara, CA 93106, USA
a4 National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA. 7600 Sand Point Way NE, Seattle, WA 98115, USA

Article author query
emslie s   [PubMed][Google Scholar] 
fraser w   [PubMed][Google Scholar] 
smith r   [PubMed][Google Scholar] 
walker w   [PubMed][Google Scholar] 

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.

(Received January 2 1998)
(Accepted May 29 1998)


Key Words: abandoned colonies; Adélie penguins; climate change; palaeodiet; palaeoecology.

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