Terrestrial habitats on sub-Antarctic Marion Island: their vegetation, edaphic attributes, distribution and response to climate change

Abstract

The vegetation, soil chemistry characteristics and altitudinal distributions of 23 habitats in 7 habitat complexes on sub-Antarctic Marion Island (47°S, 38°E) are described. The habitat complexes (number of habitats in complex) are; Coastal Salt-spray Complex (2); Fellfield Complex (2); Slope Complex (6); Biotic Grassland Complex (3); Biotic Herbfield Complex (3); Mire Complex (6); Polar Desert Complex (1). The habitat classification closely reflects the between-habitat variation in the relative magnitudes of the main forcing variables that determine ecological succession on the island (moisture, exposure, parent soil material, saltspray and manuring and trampling by seals and seabirds). Hence, it can serve as a framework against which to detect and evaluate ecological responses to the marked climatic change currently occurring in the sub-Antarctic. Suggestions are made on how the habitats might respond to climatic change (warming, drying) and other perturbations (increasing or decreasing influences of salt-spray and manuring).