THE BREEDING BIOLOGY AND DISTRIBUTION OF ADELlE PENGUINS: ADAPfATIONS TO ENVIRONMENTAL VARIABILITY

• Main Authors: Wayne Z. Trivelpiece, William R. Fraser
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Southern Ocean; The Antarctic; Weddell; Antarc*; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.6410; http://pal.lternet.edu/docs/bibliography/Public/083lterc.pdf

Adtlie penguins are long-lived, highly philopatric seabinls Iilat dominate the bird biomass of the Western Antarctic Peninsula region, and serve as focal animals for our Long·Tenn Ecological Research (LTER) study of the effects of environmental variability on animal populations in the Antarctic marine ecosystem. The major pbysica1 factors affecting the breeding success, distribution and demography of Adl!lie penguins in the Southern Ocean are variability in sea ice cover, ocean circulation patterns and terrestrial topography _ We analyzed Ad~tie distributions in the Antarctic Peninsula region and concluded that Ad~lie penguins have discrete subpopulations in the nonheaslem and southwestern regions of the area. These 5ubpopulations are separated by a 400 kIn gap in their respective distributions, but each is within several hundred kilometers of predictable pack ice areas in the Weddell and Bellingshausen Seas, respectively. We propose that these pack ice areas are the wintering grounds for each subJXlPUlation, and that access to these pack ice areas, early in the season following courtship fasting. is the key to successful breeding in A~lies. We further analyzed the colony distributions within each subpopulation and found highly clumped distributions of Adelie pen· guins that were strongly correlated to physicaJ factors such as bathymetry, CUJTt:nts and wind direction. We propose that these variables reduce the occurrence of pack ice in the vicinity of breeding colonies of Ad~lie penguin populations, thereby assuring access to open water in the early season. Finally, we examined the