Chemical and ecological studies on the vegetation of ultramafic sites in Britain

Abstract

The vegetation of British outcrops of ultramafic rocks occurs under a wide range of climatic conditions from the southernmost area of the English mainland to the northernmost Scottish islands. The rocks themselves vary in composition. Vegetation ranges from debris with <1% plant cover to mature deciduous woodland with a species-rich ground flora. Some species preferentially absorb magnesium, others calcium. Experiments demonstrate the existence of plant races, collected from ultramafic soils, which are tolerant to relatively high concentrations of Ni and Mg. Nutrient limitation prevents full cover developing on some sites. Recent work suggests the importance of drought in maintaining sites in an open state and this may interact with nutrient limitation. -from Author