Pattern in the Simple Moss-Turf Communities of the Sub-Antarctic and Maritime Antarctic

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Abstract
Grids of 1500 (300 .times. 5) 2 .times. 2 cm quadrats were recorded on 3 moss-turf sites: South Georgia in the Sub-Antarctic (3 dominant species), the maritime Antarctic on Signy Island (2 dominant species) and Galindez Island (a virtual monoculture of Polytrichum alpestre). Two methods of pattern analysis, the stepped blocked quadrats variance method and 2-term local quadrat variance method, were used on all data. As yet no technique is satisfactory for exploring pattern in belt transects. The pattern in the simplest of these communities, Galindez Island, is probably due to the alternation of mossy areas, or hummocks, and bare ground. At Signy Island there is a well developed pattern, with 2 scales of heterogeneity at about 20 cm and at 1.2-2.0 m. The latter is considered to be due to the history of vegetation development, which is determined by the distribution of rocks beneath the surface of the moss carpet. The South Georgia community has 2 scales of pattern similar to those on Signy Island, but the factors determining them are unknown. In this 3-spp. community both positive and negative associations are indicated. On all sites, virtually all analyses indicated a small scale of pattern at about 20 cm. This scale is important when sampling both the vegetation and the animal communities living within the moss-turf communities.