ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[Sully]

On dhole predation on tigers, I've always found that hard to believe. You see big packs of wild dogs not even go near a lion in Africa, and their numbers are demolished in lion range. I highly doubt dhole, smaller animals in similar numbered groups, would pose any threat to a healthy adult tiger, which are on average larger than your average lion. Furthermore, the study below would suggest dholes actively avoid tiger range, far from predating on the giant cats. Maybe in certain very favourable circumstances (sick/old/young/injured) a large pack of dholes would be able to overcome a tiger, but generally, I highly doubt the dogs would dare.

Competitive interactions between tigers, leopards, and dholes revealed in Kuiburi National Park

Posted on 22 August 2013
 
Tigers commonly coexist with two smaller potential competitors—leopards and dholes. Top predators like tigers often shape their communities through intraguild predation, and theory suggests that smaller predators should avoid larger ones, though the final outcome often depends on prey abundance. What are the prospects for the continued coexistence of these threatened species where prey occurs at low densities? This question is relevant for much of Asia, where predators and prey have been driven to low levels through poaching, but it has not been addressed, partly because low density populations of highly mobile animals are inherently difficult to study. 

Research by the Kuiburi Tiger Project has started to reveal the dynamics of low density predator-prey communities for the first time. The researchers tested predictions from intraguild predation theory at Kuiburi National Park, a WWF-Thailand tiger site where low density tigers, leopards and dholes compete for scarce prey. The research was recently published in the journal Biological Conservation. Sign-based occupancy surveys and camera trapping were used to investigate habitat use, spatial co-occurrence, prey selection, and activity patterns of the three predators. Obtaining the data took two years, during which the research team (which included Kuiburi park rangers) searched for tracks and signs of the predators and their prey along 128 1-km sign transects throughout a mountainous 350 sq. km study area. 50 camera traps were also monitored for four months to record activity patterns. 

Tiger habitat use was influenced mainly by the distribution of its four main prey species—pig, muntjac, gaur, and sambar. Similarly, leopard distribution matched the availability of its main prey, langur, but leopard avoided pigs—the preferred prey of tiger. Leopard and dhole had low rates of co-occurrence with tiger, indicating fine-scale spatial avoidance, and their detection probabilities were 47–52 per cent lower in tiger-occupied open grasslands (despite suitable prey there) compared to closed forest. Tigers were active mostly at night, whereas leopard and dhole were mainly diurnal, suggesting some temporal avoidance as well.

Tiger and dhole distributions in Kuiburi were strikingly divergent: dhole occupancy was 3 times higher than tiger in the north, where tigers and prey were scarce, but 4 times lower than tiger in the centre, where Kuiburi’s remaining tigers and prey were concentrated. This pattern is suggestive of mesopredator release—the release of smaller predators from top-down control on abundance and distribution after the decline of an apex predator. It is a common phenomenon around the world concurrent with the global decline of apex predators, but has not been documented before in Southeast Asia. 

In sum, tiger distribution was driven solely by prey availability, whereas leopard and dhole were influenced by a trade-off between prey availability and avoidance of tigers, mediated by habitat structure. Low density tigers face potential exploitation competition from more numerous leopards and dholes. But knowledge of the habitat-mediated risk effects we uncovered could inform tiger recovery efforts despite this disadvantage. Kuiburi National Park currently manages for wildlife recovery by creating open grasslands to improve habitat for ungulates. Our research indicates this strategy should benefit tigers in two ways. First, open habitats have higher prey diversity and abundance. Second, open habitats are used almost exclusively by tigers because of habitat-mediated risk effects—by extension, tigers should have undivided access to prey there Reply