Context dependency of top-down, bottom-up and density-dependent influences on cheetah demography.

Research on drivers of demographic rates has mostly focused on top predators and their prey, and comparatively less research has considered the drivers of mesopredator demography. Of those limited studies, most focused on top-down effects of apex predators on mesopredator population dynamics, whereas studies investigating alternative mechanisms are less common. In this study, we tested hypotheses related to top-down, bottom-up and density-dependent regulation of demographic rates in an imperilled mesopredator, the cheetah (Acinonyx jubatus). We used a 25-year dataset of lion density, cheetah density and prey density from the Mun-Ya-Wana Conservancy in South Africa and assessed the effects of top-down, bottom-up and density-dependent drivers on cheetah survival and reproduction. In contrast to the top-down and bottom-up predictions, both adult and juvenile cheetahs experienced the lowest survival during months with high prey densities and low lion densities. We observed support only for a density-dependent response in juvenile cheetahs, where they had a higher probability of reaching independence during times with low cheetah density and low prey density. We did not identify any strong drivers of litter size. Collectively, our results indicate that high apex predator abundance might not always have negative effects on mesopredator populations, and suggest that context dependency in top-down, bottom-up and density-dependent factors may regulate demographic rates of cheetahs and other mesopredators. Our results highlight the complexities of population-level drivers of cheetah demographic rates and the importance of considering multiple hypotheses of mesopredator population regulation.

Habitat complexity and lifetime predation risk influence mesopredator survival in a multi-predator system.

Variability in habitat selection can lead to differences in fitness; however limited research exists on how habitat selection of mid-ranking predators can influence population-level processes in multi-predator systems. For mid-ranking, or mesopredators, differences in habitat use might have strong demographic effects because mesopredators need to simultaneously avoid apex predators and acquire prey. We studied spatially-explicit survival of cheetahs (Acinonyx jubatus) in the Mun-Ya-Wana Conservancy, South Africa, to test hypotheses related to spatial influences of predation risk, prey availability, and vegetation complexity, on mesopredator survival. For each monitored cheetah, we estimated lion encounter risk, prey density, and vegetation complexity within their home range, on short-term (seasonal) and long-term (lifetime) scales and estimated survival based on these covariates. Survival was lowest for adult cheetahs and cubs in areas with high vegetation complexity on both seasonal and lifetime scales. Additionally, cub survival was negatively related to the long-term risk of encountering a lion. We suggest that complex habitats are only beneficial to mesopredators when they are able to effectively find and hunt prey, and show that spatial drivers of survival for mesopredators can vary temporally. Collectively, our research illustrates that individual variation in mesopredator habitat use can scale-up and have population-level effects.