Diet of dingoes and cats in central Australia: does trophic competition underpin a rare mammal refuge?

We investigated the hypothesis that trophic competition between a top predator and a smaller predator can create refuge from predation for small mammalian prey, using the dingo (Canis lupus dingo) and feral cat (Felis catus) in the MacDonnell Ranges of dryland Australia as a case study. We analyzed the diets of the 2 predator species for evidence of potential competition. There was no evidence of exploitation competition between the 2 carnivores-cats consumed mostly small mammals and particularly larger rodents, whereas the diet of dingoes was dominated by 1 species of large macropod. There was also no evidence of a shift in diet of cats, as their diets in refuges and non-refuges were highly overlapping. Consistent with interference competition, cats were the third most frequently consumed mammal species by dingoes. Although predation by dingoes could limit densities of cats across the MacDonnell Ranges, this alone does not explain why the most rugged habitats in the region are a refuge for rare mammals. We conclude that habitat complexity most likely underpins the refuge and that possible effects of dingo predation on the cat population would be of secondary importance.