Regulation of a small, discrete African elephant population through immunocontraception in the Makalali Conservancy, Limpopo, South Africa

Abstract

Populations of the African elephant, Loxodonta africana, are growing rapidly in southern Africa, to the extent that population control has become essential. The management option of translocation is no longer realistically available, whilst culling has become ethically unacceptable, especially to the general public. Previous immunocontraception trials on elephants with Porcine Zona Pellucida (PZP) vaccine demonstrated that it is safe, effective, reversible, remotely deliverable, and has had no evident adverse side effects. We demonstrate effective contraceptive management of a discrete, small population of free-roaming elephants in the Makalali Conservancy, Limpopo province, South Africa. Complete reproductive control has been demonstrated in all 18 original targeted females, who have by now passed the population's average intercalving interval of 56 months without giving birth. A zero population growth rate has been maintained within this target group since August 2002. On the basis of this small sample over a short period, immunocontraception should be considered a viable means of population management as an alternative to long-term culling strategies in small populations.