Feeding ecology of lion (Panthera Leo) in the Karoo National Park

Abstract

Lion, Panthera leo, is categorized as Vulnerable by the IUCN and their conservation is a global priority. Lion populatons find themselves increasingly confined to small, fenced reserves (< 100 000 ha) and these confined lion populatons can aid lion conservation efforts but need careful management. Following the reintroduction of lion into the Karoo National Park (KrNP) in 2010 there have been multiple escapes from the reserve’s fenced boundaries. These breakouts required expensive management intervention, lead to human-wildlife conflict, the euthanasia of some lion, and are ultimately bad for lion conservation. Understanding the drivers of lion breakouts is necessary to enable sensible pre-emptive management strategies that will minimize breakouts, reduce human wildlife conflict, protect prey populations, and ensure healthy ecosystem function. Both social dynamics and nutritional constraints can drive lion dispersal. This study focusses on lion feeding ecology and more specifically the prey species preferred and terrain characteristics of preferred hunting habitat. This project provides a greater understanding of lion feeding ecology in a small arid reserve and is thus of benefit for KrNP and other small wildlife reserves with lion, especially other reserves in semi-arid to arid regions, as well as lion conservation efforts at a global scale. Recent and historic lion diet in KrNP was analysed using historic field ranger GPS cluster analyses data, and recent GPS cluster data obtained from this study. Lion hunting habitat and the key parameters driving huntng habitat selection are investigated by measuring multiple physical attributes associated with kill sites. For each kill site, identified through GPS cluster analyses, the associated landscape type, vegetative cover, rockiness, visibility and prey availability are estimated on site. GPS cluster analysis resulted in 144 confirmed kill sites visited and 119 where large prey species (>50Kg) were identified to species level. Kudu (Tragelaphus strepsiceros), eland (Tragelaphus oryx), red hartebeest (Alcelaphus buselaphus caama), and gemsbok (Oryx gazella), made up 89% of the large prey consumed. Eland were the most consumed species and contributed the most to the total large prey biomass consumed (40%), double that of kudu which contributed the second most (19%). The 10-year historic GPS cluster data revealed kudu as the most commonly consumed large prey species (27%) and eland the greatest contributor to biomass consump;on over the 10 years by lions (30%). The lions also indicated an ability to adapt their diet according to environmental conditions where gemsbok contributed proportionally more to the diet, than in the other years, during the peak of the drought in the Karoo. An analysis of the preferred hunting habitat of lions on a broad landscape scale showed that lions prefer to feed in the drainage line woodland of the KrNP. This could potentially be attributed to the greater cover within this landscape. The most important fine-scale terrain characteristics in defining kill sites was the vegetative cover and visibility/openness. The terrain rockiness and ruggedness within a 5m radius around the kill site also proved significant. Lions showed a preference for kudu and eland, and preferred hunting habitat with greater cover. This study indicates that lions are largely dependent, especially in semi-arid areas with uneven distribution of vegetational cover, like the KrNP, on access to optimal hunting habitat where prey are catchable and not necessarily the most abundant. This study does not only provide a greater understanding of lion feeding in Karoo National Park which can assist management with decisions relating to lion management and the reduction of lion breakouts, but also provide much needed data on lion feeding ecology in semi-arid regions