Arthropod ecology in the maritime Antarctic

Maritime Antarctic areas possess a predominantly cryptogamic vegetation and support a free‐living invertebrate fauna showing few species in great abundance. Between January 1962 and April 1964 a study was made of the arthropods and to a lesser extent the nematodes from some such areas. The preliminary results of this work are presented. The terrestrial habitats are broadly classified according to their degree and type of vegetation. Each of the Maritime Antarctic areas visited is then dealt with separately, a brief description of the general environmental features being followed by an account of the fauna collected at individual localities. Data are given where quantitative sampling was possible, and some results are presented from the more detailed ecological work carried out at Signy I, South Orkney Is. of the arthropods collected, seven species of Collembola, twenty species of Acarina, and one dipteran are clearly indigenous to the Maritime Antarctic. A few taxa are widespread within the region but considerable variation exists between the species content of different areas. Cryptopygus antarcticus is the dominant arthropod. Arthropods are present in most terrestrial habitats free from permanent ice but the highest densities occur in vegetation, where they are concentrated in the upper layers. Only a few free‐living species exhibit a high degree of habitat specificity. The absorption of direct radiation by moss and soil in summer and the insulating effect of winter snow have a profound effect on the temperature regime of the terrestrial microhabitats. As well as supporting a more luxuriant vegetation, localities affected by fumarolic heat possess a more diverse and abundant fauna. The ecological distribution of the arthropods is discussed in relation to some physical and biotic factors of their habitats.

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