Impacts of selective bush control on herbaceous diversity in wildlife and cattle land use areas in a semi-arid Kalahari savanna

Abstract

Climate change and inappropriate management practices in semi-arid savannas often result in shrub encroachment. Chemical shrub control is a common rehabilitation measure to counter shrub encroachment. A recent development, particularly in southern Africa, is the conversion from cattle to wildlife farming. Cattle and wildlife exhibit different behaviours, and different management practices are used. How these differences affect the results of rehabilitation measures is not well known. Here, we compared how selective chemical shrub control in these two land uses affected herbaceous diversity, and composition along waterhole transects (proxy for grazing pressure). Shrub control increased Simpson diversity when both land uses were analysed together, while land use type did not affect any diversity measure. However, when land uses were analysed individually, spatial differences in diversity became apparent. Species richness in game farms was affected by shrub control only at distances greater than 300m from waterholes, and in cattle farms total abundance increased at 1000m distances. Eleven species contributed to compositional differences between land uses. Our results show that bush control can improve ecosystem functioning and habitat heterogeneity in both land use types, which is particularly important given the current transition from livestock to game farming in southern Africa.