Impact of land use on occupancy and abundance of terrestrial mammals in the Drakensberg Midlands, South Africa

Abstract

Better management and knowledge regarding the effect of land use intensification on mammal abundance and occupancy is crucial for species conservation. This is particularly true in dynamic forest-farmland mosaics subjected to rapid human-induced habitat alterations for agricultural practices. We conducted camera-trap surveys at 44 locations across farmland use gradients between October 2012 and January 2013. We estimated occupancy and relative abundance of 10 terrestrial mammals in response to farmland use in the Drakensberg Midlands, South Africa. Occupancy modelling revealed the importance of available forest and wetland to several mammals. Occupancy estimates for Leptailurus serval were lower in cropland than for Herpestes ichneumon, Atilax paludinosus and Potamochoerus larvatus. Occupancy of Leptailurus serval and Redunca rundinu increased with relative human abundance while the relationship was inverse for Hystrix cristata and Potamochoerus larvatus. Livestock-related activity influenced occupancy of Potamochoerus larvatus positively and Hystrix cristata negatively. Pesticide usage had a negative impact on detection of several mammals, and occupancy of Atilax paludinosus. Commercial plantation influenced occupancy of Tragelaphus scriptus and Potamochoerus larvatus positively. Plantation supported the abundance of five species positively. Wetland influenced relative abundance of Leptailurus serval positively. Pesticide use significantly decreased relative abundance of Leptailurus serval and Atilax paludinosus. Livestock and human relative abundance were positively associated with relative abundance of Leptailurus serval and Canis mesomelas and negatively for other species. Our models proved the sensitivity of some mammals towards the natural habitat loss due to agricultural practices while others appeared to be tolerant to such human-modified habitats. We suggest feasible management implications for conserving diverse mammalian assemblages in farmland mosaics.