The relative role of intrinsic and extrinsic drivers in regulating population change and survival of African wild dogs (Lycaon pictus)

Abstract

Evaluating how intrinsic (intraspecific density), extrinsic (interspecific density and prey density) and anthropogenic (management intervention) factors affect African wild dog (Lycaon pictus) population performance is key to implementing effective conservation strategies. Lions (Panthera leo) can affect wild dog populations, and in small and highly managed protected areas, populations of wild dogs and lions often co-occur at high densities. It is unknown what mediates these co-occurring high densities and how trophic interactions facilitate the persistence of wild dogs in areas with high lion densities. In this study, we modelled how intrinsic and extrinsic factors affected population change and survival of 590 individually identifiable wild dogs in Hluhluwe–iMfolozi Park (HiP), South Africa, an area with high lion density. The wild dog population in HiP grew significantly and comprised one of the highest population densities and the largest pack sizes in Africa. Pup survival rate was also the highest known in Africa, and the median individual survival was 29 months. During low lion density periods, the rate of wild dog population change increased despite low prey density, while at higher lion density, the rate of population change decreased only when prey density decreased. Survival for all age classes increased as population density increased, suggesting there is an important density-dependent effect on survival for all age classes that manifests at the population level. While increasing lion density had negative effects on adult and yearling survival, it did not affect pup survival. Our results suggest that both intrinsic and extrinsic drivers regulated the HiP wild dog population. Importantly, populations of wild dogs in small (~ 900 km2), fenced protected areas are highly adaptable and can co-exist at high levels of interspecific competition over many generations as long as there is an intact and abundant prey base.