Black Rhinoceros Conservation Research in Southern Africa
It can take from three weeks to three months for a black rhino to establish a predictable home range after relocation.
Dr. Wayne Linklater, Millenium Postdoctoral Fellow, and Dr. Ron Swaisgood of the Giant Panda Conservation Division of the San Diego Zoo's CRES began a research program in 2001 to better understand black rhinoceros Diceros bicornis behavior in the wild. In some habitats, when a portion of a black rhino population is removed, the remaining population does not recolonize the area. Moreover, when black rhinos are released at new sites it is best that they establish home ranges and normal behavior patterns as soon as possible to reduce the probability of death or injury resulting from fighting, accidents, or stress. The goal of the program has been to investigate how spreading rhinoceros dung might be used to facilitate the recolonization and establishment of black rhinos in new habitats.
On 4 game reserves in Namibia and 10 in South Africa, 62 black rhinos were fitted with horn-implant radio transmitters and monitored between 2002 and 2004. Observations of these black rhinos revealed how they organize themselves on the landscape, respond to the removal of neighboring rhinoceroses, settle into new habitat, establish home ranges after release, and how their behavior might be managed by spreading dung in the emptied and receiving habitats. Preliminary results suggest that dung broadcasting may be a useful tool in managing black rhinoceros behavior after release by encouraging initial confident movements into a reserve, facilitating site loyalty and reduced daily movement within the reserve.
CRES has also supported a study investigating whether substantial removals of black rhinos reduce habitat quality by allowing trees to outgrow rhinos' browsing reach. The results of the study suggest that trees grew into taller, less selected and accessible height classes after rhinos had been removed. This important work suggests that black rhinos feeding may maintain favored woody plants at the preferred browsing height and indicates that removals of black rhinos from donor reserves may need to be carefully distributed across the landscape to maintain browsing pressure.
