Elephants in the Waterberg : impacts on woody vegetation by breeding groups compared with bachelors

In May 1994 IFAW funded the relocation of 50 elephants from the Kruger National Park to Welgevonden Private Game Reserve in the Northern Province, South Africa. Impact by the elephants on the vegetation of this reserve has since become a concern. The aim of this study was to quantify impact by the elephants on the woody vegetation by investigating vegetation and habitat use by elephant bachelor and breeding groups. This was determined by comparing resource use between sexes within seasons, and within sexes between seasons. Data were collected at two ecological scales: feeding patch scale and habitat scale. Feeding data were collected from 202 food plots, defined from 161 elephant sightings. In the dry season, when resources are often limited, no difference in feeding patch use was found between bachelor groups and breeding groups. This may suggest a lack of inter-sexual competition and could therefore suggest that the elephant population is currently below carrying capacity. Three habitat types are available to the elephants: plateau, hillslope and valley bottom. Both bachelor groups and breeding groups preferred valley bottom in comparison with habitat availability, in both seasons. When sexes were compared within seasons, in the dry season, bachelor groups used valley bottom more and breeding groups used hillslope more.