Introduced cats Felis catus eating a continental fauna: inventory and traits of Australian mammal species killed

摘要

Mammals comprise the bulk of the diet of free-ranging domestic cats Felis catus (defined as including outdoor pet cats, strays, and feral cats) in most parts of their global range. In Australia, predation by introduced feral cats has been implicated in the extinction of many mammal species, and in the ongoing decline of many extant species. Here, we collate a wide range of records of predation by cats (including feral and pet cats) on Australian mammals and model traits of extant, terrestrial, native mammal species associated with the relative likelihood of cat predation. We explicitly seek to overcome biases in such a continental-scale compilation by excluding possible carrion records for larger species and accounting for differences in the distribution and abundance of potential prey species, as well as study effort, throughout each species' range. For non-volant species, the relative likelihood of predation by cats was greatest for species in an intermediate weight range (peaking at ca. 400 g), in lower rainfall areas and not dwelling in rocky habitats. Previous studies have shown the greatest rates of decline and extinction in Australian mammals to be associated with these traits. As such, we provide the first continental-scale link between mammal decline and cat predation through quantitative analysis. Our compilation of cat predation records for most extant, terrestrial, native mammal species (151 species, or 52% of the Australian species' complement) is substantially greater than previously reported (88 species) and includes 50 species listed as threatened by the IUCN or under Australian legislation (57% of Australia's 87 threatened terrestrial mammal species). We identify the Australian mammal species most likely to be threatened by predation by cats (mulgaras Dasycercus spp., kowari Dasyuroides byrnei, many smaller dasyurids and medium-sized to large rodents, among others) and hence most likely to benefit from enhanced mitigation of cat impacts, such as translocations to predator-free islands, the establishment of predator-proof fenced exclosures, and broad-scale cat poison baiting.