Effects of management intervention on elephant behaviour in small, enclosed populations.

Abstract

The continual increase in elephant numbers across southern Africa raises concern, though the interventions to manage these populations are more contentious. Within small, enclosed reserves active management is necessary to limit elephant impact. Various management tools exist with which to control fluctuations in elephant population numbers or density and simulate natural large stochastic events to control population growth. During this study, undertaken in the Munyawana Conservancy, KwaZulu-Natal, and Pilanesberg National Park, North West Province, South Africa, several management options were implemented. In order to lower the population numbers, family groups were translocated from the Munyawana Conservancy to other reserves, while to reduce population growth rate an immunocontraception was implemented. Both conservation areas introduced older bulls to normalise the bull population age structure, and expanded the conservation area by inclusion of new land to reduce population density. The influence of these management interventions on the elephant population were measured by their social, behavioural, spatial and movement responses. The older bull introduction was successful as bulls set up exclusive bull areas. There was a quick, subtle affect on the bull groups' size immediately after the older bull introduction, while there was no immediate change within the resident bulls' musth behaviour or duration. During area expansion, elephants appeared to perceive the new unexplored area as a threat although this threat became reduced through time as they became more familiar with it. The spatial scale of response was relatively small, while the temporal scale of response was relatively large. Rotational immunocontraception was shown to be a successful tool to alter herd structure by aging the population and maintaining a low population growth rate. The process of immunocontraception darting had no significant effect on herd associations and movement rates, accordingly the duration of the disruption effects were short lived. During multi-management interventions, no differences were found within the elephant social grouping. Management interventions may pose unforeseen social risks and different populations may respond differently to management induced stress. Therefore, interventions need to be considered for each elephant population which will achieve the conservation area's objectives with the most effective outcome, but with lowest holistic impact.