"The Influence of Veterinary Control Fences on Certain Wild Large Mammal Species in the Caprivi Strip, Namibia"

Rowan B. Martin

This paper is based on consultancies carried out for the Ministry of Environment and Tourism, Namibia from October 2002-April 2003 to develop management plans for Southern Savanna Buffalo (Syncerus caffer caffer), Roan Antelope (Hippotragus equinus), Sable Antelope (Hippotragus niger niger) and Tsessebe (Damaliscus lunatus lunatus).

Rainfall is ultimately the factor limiting the distribution and abundance of these species in southern African savannas. Prior to the great rinderpest epidemic at the turn of the 19th century, the range of buffalo extended to all parts of southern Africa with an annual rainfall exceeding 250mm. Rainfall determines not only the final carrying capacity of the range for buffalo but also the age of first conception and fecundity of females. Roan, sable and tsessebe do not occur naturally in areas where annual rainfall is less than 400mm and their numbers are strongly correlated with the long term cumulative surpluses and deficits above and below the mean annual rainfall.

The Caprivi is the only part of Namibia which enjoys an annual rainfall above 500mm and it is to be expected that the area would carry populations of all of these species at densities of the order of 1-2/km2. In northern Botswana in the area contiguous with the Caprivi, buffalo numbers may be as high as 100,000 and there are substantial populations of roan (1,500), sable (3,000) and tsessebe (10,000). Immediately across the international boundary, the abundance of these species decreases drastically and the populations are fragmented into isolated subpopulations.

A range of potentially limiting factors was examined to assess the primary causes of the species’ poor conservation status. In the eastern Caprivi, poor land use planning may be the primary factor limiting wild species. The ad hoc westward expansion of humans and domestic livestock threatens the integrity of the range for all wild species. Wedges of human settlement are fragmenting the range and, in several places, continuity of species populations can only be maintained through spatial links with northern Botswana. Any ill-considered placement of veterinary fences in this area would be likely to result in the total isolation of a number of small subpopulations and, ultimately, their demise. In the western Caprivi (the Caprivi Strip), the present location of veterinary fences has caused the isolation of Mahango and Khaudum National Parks and effectively broken all linkages not only between the east and west Caprivi but also between Botswana and Namibia. At a time when there are high expectations for trans-frontier conservation areas, this is a retrogressive development. Various alternative configurations and mitigating measures for veterinary fences were recently proposed in a major study commissioned by the Botswana government but, as yet, no decisions have been reached which alter the status quo.

Conservation issues here may be secondary to the long-term development potential for the Caprivi and northern Botswana based on wildlife management as the primary form of land-use. The financial and economic values offered by wildlife far exceed those possible from domestic livestock.