The Festuca-Agrostis Grassland Complex in South-East Scotland

Abstract

The complex of biotic Festuca/Agrostis grassland and grass-heaths in a part of the Cheviot Hills of South-east Scotland has been analysed and described in relation to the environment. Within the area sampled, the chief factors contributing to environmental variation were soil base status, soil moisture regime, grazing pressure and the effects of selective grazing among species. The soil data were used as a basis for an axis of environmental variation along which the stands were ordinated using their floristic characteristics for this purpose. The vegetation was found for the most part to vary continuously, though small discontinuities occurred, related to changes in habitat factors. It was concluded that the true nature of the floristic continuum could best be expressed in terms of a uni- or multi-dimensional ordination and that any classification should be based on this. A series of Nardus-dominant communities were found which had arisen from the Festuca/Agrostis communities as a result of selective sheep-grazing. There was some evidence, however, that not all types of Festuca/Agrostis and grass-heath are equally susceptible to invasion by Nardus and that low soil base status or increased soil moisture are predisposing factors favourable to Nardus. A classification is given of the complex of Festuca/Agrostis grasslands and grass-heaths based on the ordination of the vegetation. Data are presented on the floristic composition, soil profile type and chemical analysis of each vegetation type and these are discussed in relation to other published accounts.