High elephant impact is capable of converting tall mopane woodland to shrubland in the South East Lowveld of Zimbabwe

Includes bibliographical references.African elephants are known to be important agents of structural and compositional changes in several vegetation types in southern Africa. This is of concern for biodiversity conservation and management of wildlife areas in the region. This study assesses how increasing elephant numbers have already altered and are likely to continue to modify the structure and composition of mopane woodlands in the south-eastern lowveld of Zimbabwe. Several features of vegetation structure and composition were quantified and compared across areas under three different elephant densities: low, intermediate and high. We assessed the degree, nature and patterns of damage incurred by woody plants within these woodlands to determine how elephants are both driving and responding to the changes in the vegetation. Increasing elephant densities were associated with increased losses of tall trees and the resultant development of a coppiced shrub layer. As elephant densities increased from low to intermediate levels, so did the level of damage to both shrubs and trees. However, elephants appeared to exhibit a functional response such that the increase in damage to the shrub layer was proportionately higher than to trees, probably because the coppiced shrub layer was a preferable food source. Nevertheless if elephant density increases further to high levels, damage to trees is likely to continue increasing suggesting that tree losses are likely to continue. In particular, the high level of bark damage to emergent trees is predicted to contribute greatly to further tree losses. This study provides evidence to suggest that increasing elephant impact is capable of completely converting tall mopane woodlands to shrublands. This is likely to have indirect effects on the ecosystem functioning and diversity of these areas as well as tourism, and is consequently of concern for local management. Continued monitoring of these woodlands and management of elephant abundance is advisable if a total conversion to shrubland is to be avoided