Tigers, leopards, and dholes in a half-empty forest: Assessing species interactions in a guild of threatened carnivores

Abstract

Top predators often shape their communities through intraguild predation. Few studies have examined communities in which all three components—top predator, intermediate predators, and prey—occur at low densities; such disturbed systems are commonplace in Asia. We tested predictions from intraguild predation theory at a site where low density tigers (top predator), leopards and dholes (intermediate predators) competed for scarce prey. We employed occupancy modeling using sign surveys and camera trapping to investigate prey selection and spatial co-occurrence. Tiger and leopard occupancy matched the availability of their respective prey species, but leopard avoided pigs—a favored prey of tiger. Leopard and dhole had low rates of co-occurrence with tiger, and their detection probabilities were 47–52% lower in tiger-occupied open habitat (compared to closed), despite suitable prey there. Tiger occupancy was highest in prey-rich zones, whereas dholes were concentrated in a prey-poor zone where tigers were scarce, suggestive of mesopredator release. Activity periods of leopard and dhole (diurnal) were significantly different from tiger (nocturnal). In sum, tiger distribution appeared to be driven solely by prey availability, whereas leopard and dhole seemed to be influenced by prey availability and avoidance of tigers, mediated by habitat structure. Results agree with predictions that under intraguild predation the dominant predator’s distribution matches its resources, whereas intermediate predators trade-off food and safety. Knowledge of habitat-mediated risk effects could inform recovery efforts for low density tigers facing potential exploitation competition from more numerous leopards and dholes.