The effect of land-use on the vegetation communities along a topo-moisture gradient in the mid-Fish River valley, South Africa

Abstract

The objectives of this study were to identify the major physical environmental variables affecting plant community distribution, and to determine whether a shift occurred in plant community position along an environmental gradient of different land-use practises. To achieve these objectives the study area was stratified into a number of topographical-moisture classes and the vegetation was sampled randomly within each class along the gradient. The data were analysed using canonical correspondence analysis and various statistical tests in order to determine whether the plant communities occurred at different positions along the environmental gradient under different management regimes. The study showed that rainfall and elevation are the major environmental variables within the mid-Fish River valley. The results also revealed that a change in management regime caused a shift in plant community position along the environmental gradients. This shift was towards communities occupying higher rainfall and elevation classes with increasing grazing pressure.

Keywords: desertification; direct gradient analysis; environmental gradient; Canoco; thicket biome

African Jouranl of Range and Forage Science 16(1): 1–8