Present Distribution in Namibia

Roan

The present 'natural range' for roan includes a variable number of animals in the East and West Caprivi, Khaudum Game Reserve and the Nyae Nyae Conservancy (Figure 9). These are not separate subpopulations: rather they are the extreme animals on the outskirts of the larger roan population in northern Botswana.

Other Parks:

Roan were introduced to Etosha National Park in 1970 and to the Waterberg Plateau Park in 1975. The Kaross area in the west of Etosha where the roan population is located falls below the 300mm rainfall isohyet (Figure 9) and the population has not thrived. The Waterberg population is above the 400mm rainfall isohyet (Figure 9) and has done better.

Commercial farms:

Most of the commercial farms on which roan have been introduced lie below the 400mm rainfall isohyet (Figure 9) and it is likely that the long-term survival of roan on these properties will be dependent on supplementary feeding. Ohorongo Game Reserve, lies below the 300mm rainfall isohyet and is not far from the Etosha Kaross population.

Sable

Caprivi:

Surveys of the Caprivi since 1980 suggest that there is a permanent population in several parts of the Caprivi, namely Mahango National Park, the western Core Area of the Caprivi Strip and the Kwando Triangle (Figure 10).

Parks:

Sable were introduced to Etosha in 1978 (Figure 10). Today there is a small population in the Khaobendes paddock in the extreme west of Etosha National Park which has remained fairly constant at around 50 animals for some years and there are about 30 sable in the park proper. Except for the eastern end of the Park, the entire area falls below the 400mm rainfall contour and must be regarded as marginal range for sable. Sable were introduced to the Waterberg Plateau Park in 1980 and they have increased to around 100 animals over the past twenty years.

Commercial farms:

There are a large number of sable on commercial farms (two-thirds of the national population) but the majority of the properties lie below the 400mm rainfall isohyet in marginal habitats for the species (Figure 10). As with roan, it is likely that they will require supplementary feeding in below average rainfall years to maintain their numbers.

Tsessebe

Caprivi:

Tsessebe were recorded in significant numbers in the Caprivi (Figure 11), i.e. in mahango, the Kwando Triangle and Mudumu in 1994 (ULG 1994, Rodwell et al 1995). Since then there have not been any surveys covering all of the Caprivi in a single year - however, the limited surveys which have been done (Craig 1998 and Craig 2000) suggest that the tsessebe populations in the Caprivi have almost disappeared. Craig (1998) saw tsessebe in small numbers (fewer than 30 animals) in both Mahango and in the Kwando Triangle but in the last air survey of Mahango (Craig 2000) no tsessebe were seen.

Western Parks

Tsessebe were unsuccessfully introduced to the Waterberg Plateau Park in 1980. All of the founder population died before being released from the holding paddock. In May 1984 a male was transferred from Khoabendes to Waterberg and in May 1985 14 adults were received from Percy Fyfe Nature Reserve, Transvaal (Erb 1992). The population has not thrived and only two animals are thought to be surviving now.

Commercial Farms:

There are seven populations of tsessebe on commercial farms (Figure 11), four of which number more than 20 animals. Apart from one small group (12 animals) on Kamapu-Oos,Otjiwarongo District, all of these newly established populations lie below the 400mm rainfall isohyet in far from optimum locations.

Potential Distribution of Roan, Sable and Tsessebe in Namibia

The most suitable habitats for roan, sable and tsessebe lie in the extreme north-west of Namibia where mean annual rainfall is above 500mm - primarily in the Caprivi and Kavango regions (Figure 12). Over the long term, the three species should survive above the 400mm isohyet but they will always be vulnerable to droughts in this zone.

Not unexpectedly, the highest human population densities also occur in the most favourable habitats for the three species (Figure 12). However, the parts of the former 'natural range' for roan, sable and tsessebe in which human densities exceed 10 persons/km2 are less than 10% of the total potential range and, in theory at any rate, the potential still exists for the north-west of the country to carry large populations of all three species. However, competition with cattle will reduce the available range. Namibia's Caprivi populations of roan, sable and tsessebe all lie on the fringe of the larger Botswana populations. The present international veterinary fences separating the two countries limit the movements of the animals and this could result in isolated subpopulations on either side of the fence.