Although 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.

中文翻译：

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机械清除灌木对南部非洲莱索托被侵占的山脉的影响

尽管牧场是最具社会经济价值的生态系统之一，但其退化仍然是一个世界性问题，特别是在撒哈拉以南非洲地区。莱索托山地牧场也不例外，其特点是灌木侵占和退化。因此，莱索托政府投入巨资实施全国范围内的灌木连根拔除计划。尽管该计划已经实施了十多年，但还没有科学研究评估过这种方法的生态效益。因此，当前的研究评估了机械清除灌木对莱索托植物多样性和组成的影响。采用公制带样带样方法进行分层随机抽样，通过比较先前连续三年清除灌木并停止放牧的区域的草本物种多样性和常备生物量，评估连根拔除灌木对被侵占牧场的影响。结果表明，尽管机械去除灌木增强了草本物种多样性和站立生物量，但随着灌木去除后时间的推移，这种改善效果会下降。因此，该过程的效益是短暂的，需要至少每两年重复一次才能最大限度地发挥其影响。显然，人工清除灌木可以促进草本植物（包括杂草和禾本科植物）的生长，从而改善牧场条件。因此，该技术有潜力用作牧场管理工具。