A University of NSW study has shown that wild dogs play a key role in the conservation of Australian outback ecosystems by suppressing feral cat populations.
In a paper published recently in Ecosystems, the researchers compared dingo and feral cat populations either side of the dog fence that also doubles as the border between SA and NSW.
The fence was erected in the 1880s to in an attempt to keep dingoes from attacking sheep flocks.
With a very small number of dingoes on the NSW side of the fence and much larger number on the SA side, the fence offered an opportunity to observe feral cat numbers in identical environments with and without the influence of dingoes.
University of NSW Centre for Ecosystem Science's Mike Letnic said that throughout a six year study, between 2011 and 2017, the number of dingoes, cats and their major prey species either side of the dingo fence in the Strzelecki Desert were compared.
"We collected dingo scat and cat scat and analysed them to compare diets, while we also used spotlight searches to record numbers of each as well as two of their common food sources - rabbits and hopping mice," Professor Leitnic said.
"In our spotlight searches, dingoes were pretty much absent from the NSW side of the fence, with only four spotted in our six years of study. We also observed on this side that feral cats fluctuated as their prey numbers fluctuated," he said.
"But on the SA side, where dingoes were common, the cat numbers were consistently lower."
Co-author Ben Feit said that early on in the study, both dingo and cat numbers on the SA side appeared to fluctuate along with numbers of their rabbit and hopping-mice prey, but from 2013 onwards, dingo numbers remained high while cat numbers remained low for the remainder of the study.
"In fact, the feral cats had basically disappeared by the end of 2015 and we went for a two year stretch without seeing any," Dr Feit said.
"We think the cat population took a dive because of interference competition - either from dingoes actually preying on cats, or by scaring them completely away from the same hunting ground," he said.
The study reveled that while the scat analysis showed that wild dogs and cats eat similar foods, there was not any evidence to suggest that competition for food was a major factor in how dingoes reduced cat populations.
"Prey remained plentiful on the SA side of the fence, suggesting that dingoes had a direct, rather than incidental effect on the numbers of feral cats," Dr Feit said.
Authors said the new research added to previous studies that found dingoes helped conservation efforts by keeping numbers of introduced red foxes, feral goats and feral pigs in check while also keeping kangaroos from overpopulating in certain areas.
