Dietary niche differentiation facilitates coexistence of two large carnivores

Abstract

An animal's diet is an important attribute of its niche, and affects the role that it plays in the ecosystem. Comparing the diets of sympatric species reveals the level of dietary niche overlap between them, which can be used to gauge the potential for competition, as well as each species' vulnerability to competitive exclusion. Because of a morphology adapted to predation, sympatric carnivores can have particularly aggressive and dangerous competitive interactions; the intensity of which may be directly related to the amount of overlap in prey species consumed. Using predator scat analysis and prey survey techniques, we analyze and compare the underlying mechanisms of prey selectionprey body size and group sizebetween sympatric populations of leopard Panthera pardus and lion Panthera leo, to test for possible means of competitive avoidance between them. Because leopard and lion differ in both size and social structure, we controlled for the differing prey handling ability of each species, and found that there was still a significant difference in mean prey body size preference between the two carnivores (P = 0.050), despite a relatively high level of dietary niche overlap (0.717). Both species avoid prey in larger groups, but the tendency is more pronounced for leopards. Where intraguild competitors overlap spatiotemporally, dietary niche segregation such as this may be a mechanism through which competition is avoided and, in the case of carnivores, could reduce the frequency of potentially costly interactions.

Niche overlap and dietary resource partitioning in an African large carnivore guild

“…These competitive dynamics often affect the intensity of top-down forces by influencing predator densities, demographics and their distributions (Polis et al, 1989;Creel & Creel, 1996). As sympatric large predators do not uniformly select for resources (Hayward & Kerley, 2008), coexistence is expected to arise from shifts in niche dimensions, such as spatiotemporal and forage partitioning (Balme et al, 2017;du Preez et al, 2017). Large carnivore populations are generally regulated by the abundance and availability of their primary food items (Karanth et al, 2004;Hayward & Kerley, 2008).…”

Stuck amongst introduced species: Trophic ecology reveals complex relationships between the critically endangered Niau kingfisher and introduced predators, competitors and prey

“…Bonnaud et al 2009) and the potential for exploitative competition or competitive exclusion evaluated by measuring trophic overlaps between species (e.g. Du Preez et al 2017). However, when prey are numerous and not limiting, high diet overlap does not necessarily imply significant competition (Cupples et al 2011).…”

Specialisation in prey capture drives coexistence among sympatric spider‐hunting wasps

“…Sister taxa often avoid competition by exploiting resources in distinct areas (Schoener, ; Bulleri et al , ; Cardillo & Warren, ) or at distinct times (Santos & Presley, ; Vieira & Paise, ). Alternatively, sister taxa can reduce competition by exploring distinct prey types, as is frequently observed in predator species (Svanback & Bolnick, ; Purcell et al , ; du Preez et al , ). For example, two sympatric marine reef fishes, Embiotoca jacksoni and Embiotoca lateralis (Embiotocidae), feed on prey with distinct sizes, thus avoiding competition.…”