A New Approach to Scottish Mountain Vegetation

The methods of vegetation analysis and description developed in the Breadalbane district of Perthshire (Poore, 1955) have been applied more widely to the mountain vegetation of the Highlands. The principal ecological factors at work in determining vegetation development in the Scottish mountains are first described, with particular emphasis on hitherto neglected aspects such as the influence of snow cover and the degree of oceanicity. Comparisons are also made with the situation in Scandinavia. The inter-relationship of altitude and exposure is shown in the form of diagrams for three key areas of the Highlands. Examples of Sub-Alpine scrub, dwarf shrub heaths and bogs, moss heaths, Dryas heaths and snow-bed communities are then described in detail. These can be divided into two categories; communities which, like the Rhacomitrium heaths, have part of their principal range in Scotland, and which are well enough represented to show a response to change in the ecological factors in different parts of the country, and those such as Dryas heath, which occur in Scotland only as the scattered fragments of well-known vegetation types of Scandinavia. Salix myrsinites scrub, Betula nana bog, lichen heath, Dryas heath and certain moss and dwarf shrub heaths are here described for the first time from Scotland.