Competition refuges and coexistence: an example from Serengeti carnivores

1. In the last two decades predator-prey models have shown that 'refuges', in which prey can seek respite from predation, are crucial for the persistence of prey and predator. This concept is equally applicable to interspecific competition and, in a heterogeneous environment, species with low competitive ability should seek out 'competition refuges' where competition is reduced. 2. Cheetahs have low competitive ability compared with their principal competitors, hyenas and lions, which are directly responsible for their low density. This study uses distribution data collected in the Serengeti National Park in Tanzania over a 4-year period to show that cheetahs are more strongly associated with each other than with their competitors and utilize areas with low-density prey. 3. Cheetahs exhibit local avoidance behaviour in both space and time with respect to lions and hyenas. This behaviour is facultative and is strongest when cheetahs are engaged in activities that might expose them to food loss or increase the risk of close interactions, such as when they are hunting or eating. 4. Lactating cheetahs, whose range is restricted, are more likely to have difficulties finding prey and come into more frequent contact with lions than free-ranging animals. 5. It is argued that although cheetahs always lose in direct competition, they persist in the ecosystem by seeking out 'competition refuges' with low densities of lions and hyenas and that their mobility is the key to their continued coexistence with these predators. This pattern of distribution may be generally applicable to other species which, although widely distributed, always occur at low densities.