Restoring bare patches in the Nama-Karoo of South Africa

Abstract

Often veld degrades to a point beyond which vegetation cover, plant density and species composition do not recover despite the removal of the grazing impact. In such cases restoration interventions become necessary to assist with the re-establishment of vegetation. The efficacy of different techniques for the restoration of bare patches in the Nama-Karoo was investigated. Five different treatments, namely tilling, seeding and brush packing, and combinations thereof, were tested on the farm Hillmore in the Beaufort West district. Sown-in species established significantly better in the tilling+seeding+brush packing treatment (TSB), with Chaetobromus dregeanus and Atriplex semibaccata the most successful species. Important grazing species from the surrounding vegetation also established successfully in the different treatments. The tillage treatments were the most effective, especially the TSB treatment, which had significantly higher plant density and species richness than the other treatments. The results show that bare patches in the Nama-Karoo can be successfully revegetated with tillage treatments providing for rapid recolonisation of plants in the short term (over two years), and the tillage and seeding plus brush packing providing similar plant densities in the medium term (after five years). The tillage treatments resulted in higher plant density and species richness than the other treatments in the short term, a result that persisted with regard to species richness but not plant density in the medium term.

Keywords: cultivation, degradation, introduced species, vegetation changes

African Journal of Range & Forage Science 2007, 24(2): 87–96