A GRADIENT ANALYSIS AND SELECTION OF KEY ECOLOGICAL SPECIES FOR VELD MANAGEMENT IN A DEGRADED ENVIRONMENT NEAR VILLA-NORA, NORTH-WESTERN TRANSVAAL, SOUTH-AFRICA

An indirect gradient analysis was carried out on vegetation and enviro nmental data collected in a disturbed area of the Mixed and Arid Sweet Bushveld near Villa Nora, north-western Transvaal. Vegetation ordinat ion axes were correlated with environmental variables deduced to have influenced plant species composition. Soil type proved to be the most significant variable, followed by bush density and canopy cover. Herba ceous species most responsive to the discerned gradients were selected as key ecological species using multiple regression analysis. These s pecies are useful indicators of habitat type and range condition.