Classification of the terrestrial habitats on Marion Island based on vegetation and soil chemistry


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Abstract. Soil chemistry and vegetation data for 176 sites on sub-Antarctic Marion Island (47° S, 38° E) were subjected to Canonical Correspondence Analysis. 21 habitats in six habitat complexes were recognized from a clustering analysis of the site scores on the canonical axes. Another two habitats and one habitat complex were added to this. The resultant 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, salt-spray and manuring and trampling by seals and seabirds). It can be used by persons with a minimum of botanical or soil expertise. The habitat complexes (number of habitats in complex) are: Coastal Salt-spray Complex (2); Fellfield (2); Slope (6); Biotic Grassland (3); Biotic Herbfield (3); Mire (6); Polar Desert (1). A key is provided whereby the habitat to which a particular site belongs can be determined using botanical criteria, although infrequently soil moisture and pH information is also needed. Summaries of the soil chemistry and vegetation characteristics of the various habitats are also provided.