Resource availability is a key component in animal ecology, yet the manner in which carnivore populations respond to spatial and temporal fluctuations of resources remains unclear. We take a population‐level approach to determine how resource pulses, in this case a temporary hyper‐abundance of prey, influence the densities and space‐use of cheetahs Acinonyx jubatus. The Maasai Mara in Kenya experiences an annual migration of > 1.4 million wildebeest Connochaetes taurinus and large numbers of zebras Equus quagga and Thomson's gazelle Eudorcas thomsonii thereby providing a natural experiment to examine the influence of resource pulses on carnivore movement and densities. To draw inferences on fluctuating cheetah densities and space‐use, we collected unstructured search‐encounter data during eight sampling sessions, four during and four out of the migration, and analysed these using Bayesian spatially‐explicit capture–recapture (SECR) models with sex‐specific detection function parameters. Both densities and space‐use fluctuated seasonally but this varied according to sex. Local cheetah densities increased in areas and during times when prey abundance was highest but this was more pronounced for females than males. In terms of space‐use, movements were larger during the migration than out of the migration but this was more pronounced for males than females. These results suggest that males are influenced more by resource distribution whereas females by resource abundance. Overall densities did vary but there was no clear pattern in relation to resource pulses. Understanding the behavioural drivers of population dynamics in relation to resource pulses can provide important insights into ecological processes at multiple ecological levels.

No abstract

Optimal foraging theory predicts that carnivores select prey species based on intrinsic factors, such as body size, vulnerability, and abundance. Prey abundance can vary significantly, especially when prey species move in and out of an area en masse in search of food. However, little is known about how these resource pulses influence the prey profiles of large carnivores. Using data on lion (Panthera leo) and cheetah (Acinonyx jubatus) kills in the Maasai Mara in Kenya, we investigate whether changes in prey abundance, as a result of a mass annual migration of herbivores, influence the prey profiles of these two carnivore species. Furthermore, for cheetah we investigate whether there are sex-specific differences in prey profiles in response to changes in prey abundance. Using data from 387 lion kills and 220 cheetah kills (160 female and 60 male), we found that changes in prey abundance had a strong influence on prey profiles, but that for cheetahs this varied by sex and social grouping. More specifically, during the migration, when there is an influx of wildebeest (Connochaetes taurinus), lions and male cheetah (particularly those in coalitions) were more likely to feed on wildebeest than out of the migration. In addition, when wildebeest were less abundant, lions switched to buffalo (Syncerus caffer). Overall, the breadth of the prey profiles was narrower during the migration compared to out of the migration but this was most significant for lions and coalitions of male cheetahs. These changes in prey profiles could have an impact on herbivore dynamics, human-wildlife conflict and ecological interactions more broadly. Through the detailed characterisation of prey profiles, we contribute to the understanding of predator-prey dynamics and trophic interactions in complex, multi-species ecosystems and illustrate the importance of taking into account inter-and intraspecific variations in predators when modelling predator-prey dynamics.

No abstract