Neighbouring countries

The countries neighbouring Namibia with populations of roan, sable and tsessebe are Angola, Botswana, Zambia and Zimbabwe. No data is to hand for Zambia and Angola.

Botswana

ULG (1995) produced pooled estimates of the northern Botswana roan, sable and tsessebe populations which can be compared with the estimates for the Caprivi in 1994 when two comprehensive surveys were carried out.

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Data Quality and interpretation - Botswana

The wildlife authorities in Botswana have systematically carried out nation-wide aerial surveys of large mammals in both dry and wet seasons for most years since 1987.

The overall densities of the three species are very low in both Botswana and Namibia. In relation to the areas involved, in 1994 the Namibian sable population was at a higher density than the Botswana population, the roan population was more or less at the same density and the tsessebe population was at a much lower density. It is perhaps to be expected that tsessebe numbers in northern Botswana would be high because of the optimum habitats in the vicinity of the Okavango Swamps. Movements of animals between Botswana and the Caprivi are likely to be at their lowest during the dry season and, therefore, the dry season estimates for the Caprivi are probably indicative of the size of the "permanently resident" populations.

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Zimbabwe

The linkages between the roan, sable and tsessebe populations in north-west Zimbabwe and the Caprivi are more tenuous than those of Botswana-Namibia 'axis'. The survey results are only presented in the context of a long term vision for a trans-frontier conservation area where these species populations are able to move freely between Botswana, Namibia and Zimbabwe. The realities of the present situation are that although veterinary control fences do not theoretically prevent movements of Zimbabwe wildlife westwards into northern Botswana,only minor movements have been recorded. This may be because the physical gap between the international boundary and the nearest permanent water supplies in Chobe National Park is sufficiently large to deter most movement except in the wet season. Beyond that, the access for Zimbabwean animals to the eastern end of the Caprivi is barred by relatively dense human settlement.

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Data Quality and interpretation - Zimbabwe

Sample count aerial surveys have been consistently and regularly carried out in north-western Matabeleland area of Zimbabwe since 1980.

Roan:The roan population in Matabeleland North was estimated at over 1,000 animals in the early 1980s. Since then it has declined drastically. The confidence intervals on the surveys in 1998 and 1999 are such that there is no significant difference between the two estimates. The present population is thought to be about 300 animals.

Sable: Numbers have remained fairly constant at about 5-6,000 animals. The areas of basalt soils in Matabeleland North provide optimum habitats for sable and the Matetsi Safari Area is renowned for its consistently high hunting trophy quality.

Tsessebe: Prior to 1995, aerial surveys in Matabeleland North focussed almost entirely on elephant, buffalo and sable, which explains the absence of any meaningful data for tsessebe which have never been abundant in this region.

The estimates for the three species permit little speculation about relationships with long term cumulative surpluses and deficits in rainfall - perhaps because the region enjoys a relatively high rainfall like Katima Mulilo (usually above 500mm).