Abstract

Bush encroachment is an environmental problem in savanna ecosystems, but it is not yet clear whether it is more prevalent in communal or ranching grazing lands. This study investigates bush encroachment dynamics in relation to two rangeland management systems under different environmental conditions in Botswana. Woody vegetation cover (WC) was measured in 10 × 10 m quadrants at 100, 200 and 300 m along 23 transect located in both communal and ranching lands. Woody plant cover and diversity were not strongly influenced by rangeland management systems (P>0.05), but were highly dependent on site effects. The encroached rangelands (WC>40%) particularly, at Matlolakgang site and also had high woody species diversity. Woody cover and diversity increased with decreasing soil clay content, but not in a linear way. The lack of variability of bush encroachment between management systems has implications for rangeland management policy in Botswana and other sandveld regions of sub-Saharan Africa.

Key words: Communal grazing, diversity, ranching, rangeland degradation, soil clay, savanna ecosystems.