Biodiversity

Under the IUCN Red Data Book system, the Southern Savanna subspecies of buffalo Syncerus caffer caffer is classified as "Lower Risk (conservation dependent)" by the Antelope Specialist Group (ASG 1998) and it is evident from the data on the Taxon Data Sheet that the subspecies cannot be regarded as threatened in any global or regional context.

Even at the national level, the Namibian buffalo population cannot be considered "vulnerable" under the criteria; although its 'extent of occurrence' in the Caprivi is less than 20,000 km2, within that range its 'area of occupancy' is greater than 2,000 km2. Because it is linked to the large Botswana buffalo population, it would not qualify for any category of threat based on population numbers.

However, the numbers of buffalo in Caprivi are are well below carrying capacity and perhaps the greatest danger to the Namibian buffalo population is the potential fragmentation which could arise if links were severed with the Botswana population due to injudicious application of veterinary control fencing (Figure 10) or the spread of settlement and subsistence agriculture within the Caprivi - resulting in the isolation of subpopulations.

Buffalo occurred widely in Namibia prior to the great rinderpest epidemic at the end of the nineteenth century but were eliminated virtually throughout the country by the disease. In the first half of the 20th century, they had successfully re-colonised part of the historic range in the north of the country but were destroyed directly and indirectly as a result of veterinary control measures. It is seen as a desirable conservation initiative to re-establish the species in some of the areas where it formerly survived.

Ecological rôle

Buffalo play a key ecological rôle as a bulk grazer. By removing a large overburden of tall grasses, they facilitate access for other large mammals which would normally avoid such habitats and their grazing tends to alter the grass sward in a manner which favours other grazers.

On private ranches in South Africa and Zimbabwe which at one time supported cattle and have since converted exclusively to wildlife landuse, it is very noticeable that the absence of large bulk grazers often results in a rank sward of tall grasses which are avoided by most wildlife species. There is now a major drive by wildlife farmers to acquire buffalo in order to rectify this type of 'unbalanced' ecosystem.

In Namibia, the majority of large private farms in the north of the country carry both cattle and wildlife. Wildlife tends to be an auxiliary land use which supplements cattle income, although

• wildlife is a more profitable land use than cattle in arid and semi-arid areas;
• the concept that wildlife and cattle may complement one another has been shown to be false (Martin 1989) - cattle detract from the higher-valued land use which is possible with wildlife when large bulk grazers such as buffalo are included in the species mix;
• the results of Taylor's (1985, p256) study suggest that buffalo use grazing resources more efficiently than do domestic livestock;

Two explanations, possibly acting in combination, offer themselves for the Namibian situation:

• Veterinary restrictions preclude the inclusion of buffalo in multi-species management systems on large ranches and, therefore, to preserve the desirable habitats for many wildlife species, cattle play the ecological rôle which buffalo would normally fulfil in 'natural' systems.
• The other contributing factor is that 'ownership' systems for cattle in Namibia are absolute - far stronger than those for wildlife. Given full devolution of proprietorship over wildlife, it is possible that wildlife as an exclusive land use would become more prevalent in Namibia.