Zonation of Vegetation Related to Penguin Rookeries on King George Island, Maritime Antarctic

Abstract

ABSTRACTBreeding penguins are the major source of nutrients for terrestrial ecosystems in the Maritime Antarctic. The impact of penguin rookeries on vegetation patterns and diversity was examined by descriptive and quantitative methods along a transect from penguin rookeries to areas distant from penguin impact. Several vegetation zones related to varying degrees of rookery impact have been recognized: (1) areas under the immediate influence of fresh penguin guano and trampling support little or no vegetation; (2) the adjacent zone is covered with nitrophilous green algae, locally also cyanobacteria; (3) the next zone is dominated by the Antarctic hair-grass; (4) further on, a zone dominated by mosses is formed; (5) finally, the zone least affected by penguin impact is dominated by lichens. With increasing distance from penguin rookeries, vegetation zones become less distinct and more complex; along consecutive zones vegetation richness and diversity increase and dominance decreases. Change in species composition is gradual with a broad overlap of species distributions, and the distinct zones are the result of differences in life-forms and growth-forms of the dominant species. This ecological gradient, comprising a few species and being relatively simple, offers unique opportunities to study hypotheses concerning ecological processes and patterns.