Species-Habitat Relationships among Antarctic Seabirds: A Function of Physical orBiological Factors

摘要

The authors employed a natural experiment to evaluate the hypothesis that a majorphysical feature of high-latitude marine habitat, the percentage of the sea covered by pack ice, affects species composition among Antarctic seabirds. The experiment entailed replicate transects through markedly altered physical habitat in the Scotia-Weddell Confluence: a series of storms caused the pact iceto advance and retreat rapidly and repeatedly over a 200-km wide area. Regardless of where their habitat moved, pack ice and open-water species occurred at significantly higher densities in the ice and open-water habitats, respectively. There were no time lags in the response of species to habitat alteration. In addition, pack-ice and open-water species had identifical diets regardless of where their preferred habitat was located. These results supported the hypothesis and showed that physical rather than biological variables affect species composition among pelagic assemblages of Antarctic sea-birds. (Copyright (c) The Cooper Ornithological Society 1993.)