Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models

SIMPLE SUMMARY: Due to continuous levels of human–wildlife conflict, habitat loss and fragmentation, the establishment of protected and enclosed reserves constitute a solid foundation for the long-term survival of threatened species. Because species living in enclosed systems often behave differently compared to their free-roaming counterparts, research is forming an important and essential tool to understand their ecology and behavior. For a population to be sustainable in a closed, fenced system, effective conservation and management strategies need to be developed on the basis of robust population estimates. We found that the study area, a protected nature reserve, is harbouring the highest leopard density in Namibia to date, highlighting that small, enclosed reserves can play a vital role for the survival of threatened species in the future. ABSTRACT: The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km(2), the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.