Impact by Elephants

There is a large elephant population in the Caprivi (5,000-10,000 animals). These elephants impact on the habitat of roan, sable and tsessebe and may be one of the limiting factors for these populations. All three species are sensitive to habitat changes and have critical habitat requirements. Physiognomic changes to vegetation structure such as those brought about by elephants are capable of a major impact on all three species. Loss of canopy trees resulting in changes to the species composition and structure of grass swards and the trampling effects of large numbers of elephant are all potentially negative influences. Overutilisation, inter-specific competition and trampling of grass by cattle and other large mammal species also renders habitats less favourable for roan, sable and tsessebe.

Roan, sable and tsessebe are specialist feeders with habitat requirements which, despite much research, may not yet be fully understood. Roan are sensitive to any increase in the density of woody plants or reduction in grass cover. Structural changes to habitats which obstruct movement, affect access to water, visibility and cover all have a major impact on tsessebe.

In the Sebungwe region in Zimbabwe all three species have been in decline for a number of years (roan and tsessebe are almost extinct). This coincides with a period where the elephant population has continued to increase and has wrought major structural changes in habitats – changes which have not been favourable to roan, sable and tsessebe. If sable and roan prefer parkland savannas with dappled sunlight shining through tree canopies to favour specific grass communities, then those conditions have gone.

There have been no population reductions of elephant in either northern Botswana or Caprivi as part of ecosystem management in recent times (if ever) and this management option could be considered. It is a topic which should be discussed jointly with the Botswana authorities.