Fighting like cats and dogs? Dingoes do not constrain spatial and temporal movements of feral cats

Abstract

The mesopredator release hypothesis proposes that when top-down suppression by a larger predator (e.g. dingoes, Canis familiaris) is removed, smaller mesopredators (e.g. feral cats, Felis catus) increase in abundance. Lethal control of dingoes could therefore potentially exacerbate predation pressure by feral cats on smaller prey species. We monitored the activity of dingoes and feral cats (in the absence of red foxes) in two dingo-baited areas over 16 months using 182 camera traps. First, we estimated population densities across each property and found that dingo and feral cat density were unrelated. Second, we compared daily capture rate of dingo and feral cats and found that both predators' capture rates were weakly related to environmental factors and the baiting program. Third, we analysed temporal overlap in activity of these two predators. Although both predators were nocturnal and showed 78.7% overlap in temporal activity patterns, there was a significant difference in activity peaks. Finally, while both predators were distributed across the whole study site, there was strong temporal separation within 1, 12 and 24 h periods at each individual camera. In conclusion, there was no indication of suppression of feral cat population by dingoes. The large and growing body of similar evidence suggests that calls to restrict dingo control on grounds that it will cause mesopredator releases are unsupported and highly unlikely to yield the biodiversity benefits often hoped for by proponents.