The immediate effects of the 1964/66 drought on the vegetation of specific study areas in the Vryburg district

Abstract

During 1964/66 the Molopo and adjacent semi-arid ranching areas experienced the most severe drought in living memory. The effects of the drought on the more important grass species in particular, were investigated on three farms in. the Vryburg district (namely Buttermere, Seruruble and Fontein). A highly significant decrease in the three dominant grass species (Stipagrostis uniplunis, Schmidtia bubosa and Eragrostis lehmanniana) was recorded in camps with a moderate stand of woody plant species at the Buttermere and Seruruble sites. Overall mean losses of 82 per cent and 80 per cent of the three major grass species were recorded at these respective sites. No significant differences in the mortality of these grass species were detected on plots from which all woody plant species had been eradicated immediately before the drought. The mean hay yields recorded (1965/66 season) from bushed and debushed camps at the Buttermere site were 96 lb and 998 lb respectively. The botanical analysis data of four "dolomite" grassveld camps of the Fontein site revealed significant decreases in the total percentage basal cover and the basal cover of the major grass plant species.

Keywords: plants|treatments|management|basal covers|grasslands|botanical analyses|yields|grasses|droughts|mortalities|Vryburg|vegetation|Molopo area|grass species|farms|dominant species|woody plants