Habitat selection by large herbivores in relation to fire at the Bontebok National Park (1974–2009): the effects of management changes

Abstract

The Bontebok National Park has long been faced with the dilemma of reconciling the need for short-interval fires, which promote grazing for bontebok, with that for longer-interval fires to maintain plant diversity. We explored habitat selection by various large herbivores in relation to veld age (time since fire), different management regimes, and vegetation type. Taller grass grazers (Cape mountain zebra and red hartebeest) were introduced in the 1980s to prolong the usefulness of older veld to bontebok through a grazing succession. We found that all herbivores favoured young veld and largely avoided veld >5 years old. Zebra and hartebeest competed with bontebok in utilising young veld rather than grazing facilitation occurring. In 2004, the fire rotation was prolonged to favour plant diversity, resulting in reduced availability of young veld. In compensation, the bontebok stocking rate was reduced. Bontebok densities subsequently declined proportionally across veld ages, thereby averting high animal densities on the smaller area of young veld. Fire significantly influenced bontebok habitat use equally during the old and new burning regimes. Herbivores did not distinguish between the two predominant vegetation types at Bontebok National Park. However, previously disturbed areas with Cynodon dactylon lawns were favoured by most herbivores despite not being burnt.