Scientific Services

The way that we manage land influences species occurrence and interactions. However, in a recent study investigating species co-occurrence along the west coast of South Africa, Debbi and Nicola discovered that intensive management of small areas also makes it difficult to detect ecological drivers.

The study was initiated in response land owner concerns that caracals were responsible for a “declining” steenbok population in the contractual Postberg section of the West Coast National Park. While predation may drive antelope abundance it is not the only process that regulates populations. The hypothesis was that historical land use and the overstocking of large herbivores may also influence small antelope populations either directly through competition or by altering habitat. Using camera traps they collected presence-absence data of terrestrial mammals across three areas (two in the park and one on a farm) to assess drivers of occurrence, species interactions and activity patterns. Some key findings are listed below;

• There was little evidence that competition or predation are regulators of small antelope abundance
• The data suggest that habitat is a driver of both small and large antelope occurrence and detection
• The overriding finding was that small areas  provide very limited scope to detect ecological patterns which would historically have taken place over much larger areas (e.g. antelope may be observed at all sites within an area, negating the power of site covariates). This makes adaptive management difficult, and is a real concern for many of the small protected areas in South Africa.
• We recommend continued monitoring over a longer time period to assess the response of small antelope and vegetation to removal of large antelope and to determine the spatial information requirements to inform management of small protected areas.

About the authors

Deborah Jean Winterton ^{1, 2}
Nicola J. van Wilgen ^{1, 3}
Jan A. Venter ^{2, 4}

1. Cape Research Centre, SANParks Scientific Services, Cape Town, South Africa
2. School of Natural Resource Management, Faculty of Science, Nelson Mandela University, George, South Africa
3. Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
4. Eugène Marais Chair of Wildlife Management, Mammal Research Institute, University of Pretoria, Pretoria, South Africa

DOI: 10.7717/peerj.8184