Does aerial baiting for controlling feral cats in a heterogeneous landscape confer benefits to a threatened native meso-predator?

Introduced mammalian predators can have devastating impacts on recipient ecosystems and disrupt native predator-prey relationships. Feral cats (Felis catus) have been implicated in the decline and extinction of many Australian native species and developing effective and affordable methods to control them is a national priority. While there has been considerable progress in the lethal control of feral cats, effective management at landscape scales has proved challenging. Justification of the allocation of resources to feral cat control programs requires demonstration of the conservation benefit baiting provides to native species susceptible to cat predation. Here, we examined the effectiveness of a landscape-scale Eradicat® baiting program to protect threatened northern quolls (Dasyurus hallucatus) from feral cat predation in a heterogeneous rocky landscape in the Pilbara region of Western Australia. We used camera traps and GPS collars fitted to feral cats to monitor changes in activity patterns of feral cats and northern quolls at a baited treatment site and unbaited reference site over four years. Feral cat populations appeared to be naturally sparse in our study area, and camera trap monitoring showed no significant effect of baiting on cat detections. However, mortality rates of collared feral cats ranged from 18-33% after baiting, indicating that the program was reducing cat numbers. Our study demonstrated that feral cat baiting had a positive effect on northern quoll populations, with evidence of range expansion at the treatment site. We suggest that the rugged rocky habitat preferred by northern quolls in the Pilbara buffered them to some extent from feral cat predation, and baiting was sufficient to demonstrate a positive effect in this relatively short-term project. A more strategic approach to feral cat management is likely to be required in the longer-term to maximise the efficacy of control programs and thereby improve the conservation outlook for susceptible threatened fauna.
Competing Interests: Rio Tinto provided funding for this study under a Threatened Species Offset Plan and a Memorandum of Understanding with the Western Australian Department of Biodiversity, Conservation and Attractions (DBCA). This commercial affiliation does not alter our adherence to PLOS ONE policies on sharing data and materials. The Eradicat® bait used in this study is manufactured and supplied by DBCA’s Bait Factory. The registration of Eradicat® in Western Australia restricts its use to fauna conservation programs on lands managed by or in agreement with DBCA. Any use in other Australian states is subject to a minor use research permit from the Australian Pesticides and Veterinary Medicines Authority. Proposals for the use of Eradicat® are assessed by DBCA’s Feral Cat Technical Committee, of which, L. Gibson is a member. All remaining authors have no competing interests to declare.