Eland browsing of Grewia occidentalis in semi-arid shrubland: the influence of bush clumps

Abstract

Grewia occidentalis plants in the study area generally occurred in bush clumps with other shrub species. Grewia occidentalis commonly occurred with Diospyros austro-africana, Rhus longispina and Rhus pollens (nurse shrubs), but seldom with Acacia kar-roo and Lycium cinereum (non-nurse shrubs). Eland browsed G. occidentalis plants at higher levels than other shrub species, but browsing was not evenly spread across all plants. Grewia occidentalis plants associated with nurse shrubs had lower levels of browsing than those growing alone and those growing with non-nurse shrubs, while G. occidentalis plants in the centre of nurse shrubs experienced the lowest levels of browsing. The latter group of plants also produced the most fruit. Eland browsing is consid-ered an important factor determining the distribution of G. occidentalis plants in the study area, while the presence of nurse shrubs is considered essential for the establishment and maintenance of the G. occidentalis population in the study area.