Prey and range use of lions on Tswalu Kalahari Reserve

Abstract

The exact ecological and economic role of lion Panthera leo populations on small enclosed reserves is poorly understood. The management and monitoring of such populations is important to ensure their long-term survival. The prey use, range use and habitat selection of an isolated lion population were investigated. The study was conducted on a small (> 1000km2), enclosed predator camp of Tswalu Kalahari Reserve, situated in the Northern Cape Province of the Republic of South Africa. The prey selection, prey preferences and prey biomass removal were determined by using indirect and direct observations. Kill sites, carcasses and scats were located by spoor tracking and opportunistic observations and collated into a prey selection list. The prey selection was used to determine any prey preferences and the prey biomass removal by the lion population. The scats data was corrected for relative prey biomass and compared to the kill data and uncorrected scat data. 19 prey types were used, with the gemsbok Oryx gazelle and blue wildebeest Connochaetes taurinus being utilized most. The lion population had clear preferences for specific small and large mammals which concurred with other studies done on Kalahari lion behaviour. The prey biomass removal (9.9kg/Lion feeding Unit/day) was higher than several other studies done on lion consumption rates. The range use and habitat selection were determined by using direct and indirect observations. The minimum convex polygon method and kernel density estimates were used to delineate the ranges of the lion population. The mean range size of the Tswalu lions (91 km2) was similar to those found for lions in more mesic environments. The lions also had clear habitat preferences which depended on the habitat preferences of the prey and the prey density. A population viability analysis, using VORTEX 9.72, was conducted. An Ecological capacity was determined and used to model various environmental scenarios. The population was found to be viable, but constant monitoring and updating are needed. Management recommendations for the conservation of lions and their prey are provided.