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