Scottish Serpentine Vegetation

Abstract

Four submontane and oceanic Scottish serpentine areas share four communitytypes: 1) herb-rich submontane sedge-grass-heath of soils of high base-status, sedge-grassland being derived from heath by grazing; 2) base-rich Carex flacca Schreb. C. demissa Hornem. mire and Schoenus nigricans L. Molinia caerulea (L.) Moench mire; 3) oceanic Asplenion viridis subarcticum (Nordhagen) of base-rich crevices; 4) Arenaria norvegica Gunn. Cardaminopsis petraea (L.) Hiit sociation of unstable, mineral-rich substrata; this is partly, on scree (Coyles of Muick), a west Scandinavian community-type of base-rich talus and, on serpentine and limestone (ultrabasic) debris (Rhum, Shetland, Sutherland and Argyll), an extension to Scotland of Faeroese and Icelandic fellfield, where sparse plant cover is maintained by cool summer climate and by winter exposure and frost-shattering. Most of the characteristic species of serpentine are confined to its debris or scree, are typical of open habitats in general, and include those found on soils of a wide pH-range and most of the basiphiles on serpentine. A few occur, otherwise, in closed habitats only when these are grazed. Endemism is likely to be the most distinctive feature of the serpentine vegetation examined.