Using a Relative Abundance Index to Determine Population Trends of Large Mammals in the uKhahlamba Drakensberg Park, South Africa, between 2000 and 2010

Abstract

INTRODUCTION The uKhahlamba Drakensberg Park (hereafter ‘UDP’) is a World Heritage Site in South Africa, which harbours globally significant biodiversity (UNEP/WCMC, 2011), and serves as the most important conservation area for montane habitats in southern Africa. Part of this conservation effort pertains to maintaining its complement of large mammal species, including the common eland (Tragelaphus oryx), grey rhebuck (Pelea capreolus), southern reedbuck (Redunca arundinum), mountain reedbuck (Redunca fulvorufula), oribi (Ourebia ourebi ), klipspringer (Oreotragus oreotragus), grey duiker (Sylvicapra grimmia), and Chacma baboon (Papio ursinus). Blesbok (Damaliscus pygargus phillipsi ) occur in the Drakensberg as an alien species (source for nomenclature: Kingdon, 2015). Large mammals of the UDP face several conservation challenges.We considered three key potential global environmental drivers of change in animal numbers. Firstly, the ongoing loss of habitat on adjacent land under either communal or commercial tenure that results in a reduction of the larger area available to mammals (Everson & Morris, 2006). Secondly, an apparent increase in poaching (Patel, O’Connor, Parrini & Krüger, 2019), and an expected increase in predation from black-backed jackals (Canis mesomelas) owing to the cessation of control of this species (Barnes, 2003), may both impact small antelope numbers (Rowe-Rowe, 1976; Rowe-Rowe, 1983a). Thirdly, the introduction of alien species may result in competition, all of which could reduce population numbers. Concerns based on field observations have been expressed about apparent population declines of klipspringer, mountain reedbuck, grey rhebuck, and oribi during the 1970s (Oliver, Short & Hanks, 1978; Rowe-Rowe, 1983b), but there has been no subsequent assessment of population trends. Ezemvelo KwaZulu-Natal Wildlife initiated a ranger-based census of relative abundance, but no formal assessment has been made of the information collected. The aim of this study was, therefore, to assess whether populations of the afore-mentioned herbivore species might be declining, and that of jackals might be increasing. In addition, with 58% of the baboon population in KwaZulu-Natal found in protected areas (Stone, Laffan, Curnoe, Rushworth & Herries, 2012), and the UDP serving as the most important of these, it was appropriate to assess their population trend. Furthermore, to determine the accuracy of the technique in obtaining recent and accurate population numbers to ultimately identify which species currently require conservation attention.