Research Results
For the last nine years Earthwatch habitat monitoring has provided baseline data on the effects of confinement of black rhinos, elephants and giraffe on Acacia (A. Drepanolobium) woodlands in the Olpejeta Conservancy, Kenya. It has been observed that elephants are largely responsible for the destruction and degradation of Acacia trees. There are significant seasonal variations in the destruction of Acacia xanthophloea by elephants at the Sweetwaters game reserve. Destruction is most critical during drought conditions. This seasonal pattern correlates positively with elephant movements and utilization of microhabitats in the reserve. Destruction is most severe in the current or past artificial salt lick areas and in drinking and elephant river crossing areas. This situation is replicated in marshy areas which are obviously dry season foraging areas. Campsites and other human habitation areas recorded less damage.
Conversely, the effect of rhino damage on Acacia reduced even as rhino numbers in the reserve increased. Rhinos continued to occupy areas of the conservancy that were least used by elephants, indicating habitat segregation.
Results from the Earthwatch project on Saving Kenya’s Black Rhinos are used to develop vegetation and zone maps which provide information needed for conservation management of Acacias, the black rhino and elephant populations. Giraffe damage to Acacia has been reduced, and trees are flowering in the old reserve section for the first time since the program began in 1999. The project findings also resulted in a management action at Olpejeta. Controlled burning in Acacia habitat was stopped after results indicated burning was detrimental to Acacias and therefore interfered with the productivity of rhino habitat.
Wahungu G. M., Mureu L. K., Kimuyu D. M., Birkett A., Macharia P. G and Burton J. (2009) Survival, Recruitment and Dynamics of Acacia drepanolobium Sjøstedt seedlings at Olpejeta Conservancy, Kenya between 1999 and 2009. African Journal of Ecology, published online 29September, 2009.
Wahungu, G.M, Mureu, L.K and Macharia, P.G (2010)Variability in survival and mortality of Acacia drepanolobium Sjøstedt following prescribed burning at Olpejeta Conservancy, Kenya. African Journal of Ecology, 48 (3): 744–750.
Wahungu, Geoffery M., Lucy K. Mureu, Yussuf A. Wato, Sarah N. Mureithi, Geoffery G. Karanja (2010) Seedling survival in Manilkara butugi Chiov. along a dispersal gradient in Kakamega forest, Kenya. African Journal of Ecology, 48 (3): 783-790