Resource depletion exerts opposing pressures on co-occurring consumers to expand diets while limiting overlap with competitors.Using foraging theory as a framework,we tested the effects of prey availability on diet sp...Resource depletion exerts opposing pressures on co-occurring consumers to expand diets while limiting overlap with competitors.Using foraging theory as a framework,we tested the effects of prey availability on diet spe-cialization and overlap among competing Asian predators:dhole,leopard,and tiger.We used scat analysis from a prey-poor site,combined with a quantitative synthesis of 40 other diet studies,to determine biomass of different prey types consumed by each predator.We then assessed diet composition in relation to prey density,and compared diet breadth and overlap between prey-poor and prey-rich sites.In prey rich areas,all three predators specialized on energetically profitable medium and large ungulates(>30 kg),resulting in narrow,overlapping niches.Each predator shifted toward less profitable small-bodied prey(≤30 kg)as preferred ungulates declined,whereas con-sumption of preferred ungulates was unrelated to small prey abundance,as predicted by foraging theory.Diet breadths doubled under prey depletion(except leopard),but overlap declined as diets diverged via species-specific traits that facilitated capture of different types of alternative prey.Asia’s apex predators adapt similarly to depletion of mutually preferred ungulates by switching to more numerous but less profitable small prey.Yet they can also partition a depleted prey base through intrinsic niche differences,thereby avoiding competitive exclusion.Our find-ings illuminate the stabilizing properties of adaptive foraging and niche differences in ecological communities,and provide insights into the behavior and resilience of Asia’s endangered apex predators in response to prey depletion in the heavily poached forests of this region.展开更多
基金funded by Fran-cois and Sheila Brutsch,WWF Germany,WWF France,WWF US,WWF Sweden,WWF Denmark,WWF Aus-tria,The Rhino and Tiger Conservation Fund(U.S.Fish and Wildlife Service),and Keidanren Nature Conserva-tion Fund.
文摘Resource depletion exerts opposing pressures on co-occurring consumers to expand diets while limiting overlap with competitors.Using foraging theory as a framework,we tested the effects of prey availability on diet spe-cialization and overlap among competing Asian predators:dhole,leopard,and tiger.We used scat analysis from a prey-poor site,combined with a quantitative synthesis of 40 other diet studies,to determine biomass of different prey types consumed by each predator.We then assessed diet composition in relation to prey density,and compared diet breadth and overlap between prey-poor and prey-rich sites.In prey rich areas,all three predators specialized on energetically profitable medium and large ungulates(>30 kg),resulting in narrow,overlapping niches.Each predator shifted toward less profitable small-bodied prey(≤30 kg)as preferred ungulates declined,whereas con-sumption of preferred ungulates was unrelated to small prey abundance,as predicted by foraging theory.Diet breadths doubled under prey depletion(except leopard),but overlap declined as diets diverged via species-specific traits that facilitated capture of different types of alternative prey.Asia’s apex predators adapt similarly to depletion of mutually preferred ungulates by switching to more numerous but less profitable small prey.Yet they can also partition a depleted prey base through intrinsic niche differences,thereby avoiding competitive exclusion.Our find-ings illuminate the stabilizing properties of adaptive foraging and niche differences in ecological communities,and provide insights into the behavior and resilience of Asia’s endangered apex predators in response to prey depletion in the heavily poached forests of this region.
