干旱区生态环境知识资源中心

We assessed past and present vegetation patterns in relation to land use on a municipal commonage in South Africa. We asked specifically whether the reassignment of the commonage for the use of historically disadvantaged town residents after 1994 has impacted negatively on the vegetation of the commonage. Analysis of land cover change using aerial photography time series revealed that the most significant human impacts on the Bathurst commonage occurred prior to 1942 due to heavy and uncontrolled communal land use. Vegetation change since then has been characterised by a recovery of thicket vegetation and an encroachment of woody species into grassland. Additional field sampling of the species composition and age class distributions of trees and shrubs in thicket and broken thicket vegetation showed these units to be of high veld condition status. Thornveld and old lands have both been encroached upon by woody species, particularly by Acacia karroo, and possessed the lowest veld condition scores. There is little evidence, however, that recent land-use activities have impacted negatively on commonage vegetation. We discuss these results in terms of the vegetation’s potential to provide for the diverse needs of commonage users, and the implications for commonage management and policy.