Roan (Hippotragus equinus) population decline in Kruger National Park, South Africa: influence of a wetland boundary

Effective management of grazers requires understanding of the mechanisms influencing population declines. Roan antelope, a specialist grazer, has declined in population numbers within Kruger National Park, South Africa. The most widely accepted hypothesis is that habitat deterioration throughout the entire northern plains landscape is responsible for declines in this species. Observations suggest, however, that on the northern plains of Kruger National Park, roan antelope grazes at the boundary between ephemeral wetland and the savanna matrix. The boundary is characterized by nutrient-rich soil and forage, and thus attracts grazing from both generalist and specialist species. We hypothesize that competition for resources at this ecotone, and not at other places in the landscape, is responsible for the observed declines in roan antelope. Changing management strategies to be more cognizant of patchiness and savanna heterogeneity, i.e. more spatially informed, will improve the likelihood that management will result in increasing roan population numbers.