Staying one-step ahead of the game: Co-existence in an African large carnivore guild

Background/Question/Methods

Most ecosystems have multiple predator species that not only compete for shared prey but also pose direct threats to each other. These intraguild interactions are key drivers of carnivore community structure with ecosystem-wide cascading effects. Yet, behavioral mechanisms for coexistence of multiple carnivore species remain poorly understood. The challenges of studying large free-ranging carnivores have resulted in mainly coarse-scale examination of behavioral strategies. This is because multivariate behavioral interactions are notoriously difficult to study empirically, as the motivation or causes of behavioral tactics may remain unrecognized without extensive knowledge of all possible interacting individuals. We overcome some of these challenges by examining the concurrent fine-scale movement decisions of almost all individuals of four large mammalian carnivore species in a closed terrestrial system. We used a comprehensive movement analysis that was based on the spatial dynamics of carnivore competitors, together with the spatial organization of prey, vegetation and abiotic habitat features. 

Results/Conclusions

We found that the intensity of intraguild interactions did not follow a simple hierarchical allometric pattern, as spatial and behavioral tactics of subordinate species changed with threat and resource levels across seasons. Lion (Panthera leo) were unrestricted and anchored themselves in areas most rich in principal prey. Because of this, the greatest cost (potential intraguild predation) for subordinate carnivores was spatially coupled with the highest potential benefit of resource acquisition (prey-rich areas). Leopard (P. pardus) and cheetah (Acinonyx jubatus) overlapped with the home-range of lion but minimized risk using fine-scaled avoidance behaviours and restricted resource acquisition tactics. Contrary to expectation, the smallest and most subordinate species (African wild dog, Lycaon pictus) did not avoid only lion, but also used multiple tactics to minimise encountering all other competitors. The trade-off between top-down competitive effects and bottom-up resource requirements for competing carnivores was dynamic and responsive to local conditions, such that greater risks were taken when resources were more of an imperative. Based on these results, we generate a more realistic representation of hierarchical behavioral interactions that may ultimately drive spatially explicit trophic structures of multi-predator communities.