Evidence against the elephant refugia and herbivore utilization hypotheses to explain low baobab recruitment in Mapungubwe National Park

The declining recruitment rate of the baobab (Adansonia digitata) across its range is evidenced by the absence of young baobabs in Mapungubwe National Park. There are several competing theories to explain this lack of small baobabs, one of which concerns the utilization and possible destruction of young baobabs by herbivores. This study aimed to test whether herbivore species composition and abundance influence baobab size class distributions and whether or not herbivores differentially utilized baobabs of different sizes. The size of trees, extent of ancient and recent damage, and the extent of herbivore utilization of baobabs were compared between Dongola Game Ranch (which has low herbivore densities and no elephants) and Mapungubwe National Park (with high elephant and other herbivore densities). The lack of very small baobabs in Dongola Game Ranch suggests that the utilization of baobabs by herbivores is not solely responsible for low baobab recruitment in and around Mapungubwe National Park. We also found no difference in the amount of recent damage to baobabs in Mapungubwe National Park and Dongola Game Ranch despite differences in the extent of herbivore utilization of the trees, again suggesting that the presence of herbivores may not have a significant impact on baobab recruitment. Other explanations for low baobab recruitment must be considered in further research.