PhD Opportunity

Drivers of mammal decline in the Tiwi Cobourg Bioregion

DSC_0162 - CopySmall mammals have undergone rapid declines in recent decades in the tropical savannas of northern Australia. Although we have a remarkably limited understanding of the causes of these declines, three interacting processes have been implicated: (1) predation by feral cats; (2) habitat modification by  frequent, high-intensity fires; and (3) grazing by exotic megaherbivores (e.g. cattle, buffalo).

The Tiwi Cobourg Bioregion in the Northern Territory, comprising the Tiwi Islands (Melville and Bathurst) and Cobourg Peninsula, is one of the last parts of northern Australia supporting a diverse assemblage of native mammals. However, there is strong evidence that mammals are declining in this region, at least on Melville Island. Recent research has demonstrated that feral cats are abundant on Melville Island, but rare on Bathurst Island and Cobourg Peninsula.

The Tiwi Cobourg Bioregion provides a remarkable natural experiment with which to explore hypothesised drivers of mammal decline. This PhD project will use this natural experiment to evaluate the hypothesis that mammals decline in areas with abundant feral cats, and that the abundance of cats is promoted by frequent high-intensity fires and abundant exotic megaherbivores.

Required skills and experience

The student will need to be have a good undergraduate academic record. They must be able to work independently, showing a high level of initiative. They will need to have field experience, and have trapped and handled small mammals. They must have the capacity to plan and implement a logistically complex field programme in remote and physically challenging environments.

Project funding and supervision

The project is fully funded and will involve close collaboration between Charles Darwin University and various stakeholders. The student would need to successfully apply for Research Training Program scholarship ($27,596 per annum) from Charles Darwin University (see, and the project will provide a scholarship ‘top up’ of $7,500 per annum for three years. The student would be based at CDU’s Research Institute for the Environment and Livelihoods (RIEL), and be supervised by A/Prof. Brett Murphy, Dr Hugh Davies and Prof. Alan Andersen.

If you’re interested in this project, please send a CV, academic transcript and a brief description of why you want this project, to

Closing date: 20 October 2019