The quantification of rangeland condition in a semi-arid grassland of southern Africa

Abstract

The degradation gradient technique was used to quantify rangeland, condition in areas ranging from poor, trampled areas close to watering points to well managed areas in a semi-arid, sweet grassland of southern Africa. Ecological values were linked to species by means of their individual positions on the degradation gradient. These species were further classified according to ecological index values. Identification of indicator species for purposes of rangeland condition assessment was done by using the correlations between the relative composition and the rangeland condition value of a species. Index values and Gaussian distribution curves were used in calculations to determine rangeland condition. The accuracy of these methods was tested and the best results were obtained by using the species curves of Themeda triandra and other species which dominate at other positions along the gradient. The advantage of this technique lies in its simplicity and ease of use. Another advantage is the fact that only the most important indicator and dominant species in the study area are used to determine rangeland condition.