Impact of mechanical shrub removal on encroached mountain rangelands in Lesotho, southern Africa

Abstract

AbstractAlthough rangelands are among the most socio‐economically valuable ecosystems, their degradation remains a world‐wide problem, especially in sub‐Saharan Africa. Lesotho montane rangelands are no exception and are characterised by shrub encroachment and deterioration. As a result, the Lesotho Government has invested heavily on a programme of uprooting the shrubs across the country. Although the programme has been implemented for more than a decade, no scientific studies have assessed the ecological benefits of this approach. Therefore, the current study evaluated the impact of mechanical shrub removal on plant diversity and composition in Lesotho. Stratified random sampling was employed using the Metric Belt Transect‐Quadrat Method to assess the effect of uprooting shrubs on encroached rangeland by comparing herbaceous species diversity and standing biomass across areas that had previously been subjected to shrub removal in three sequential years and rested from grazing. The results reveal that even though mechanical shrub removal enhances herbaceous species diversity and standing biomass, the improvement declines with time post shrub removal. Therefore, the process has a short‐lived benefit and needs to be repeated at least every 2 years to maximise its impact. It is evident that the manual removal of shrubs improves rangeland condition by enhancing growth of herbaceous plants, including forbs and grasses. Therefore, this technique has a potential to be used as a rangeland management tool.