Australasian Science: Australia's authority on science since 1938

Devils Needed on the Mainland

Reintroducing Tasmanian devils to the mainland could improve biodiversity by limiting the spread of red foxes and feral cats in habitats where dingoes have been culled, according to a study in Biological Conservation.

Tasmanian devils once lived across the Australian continent, but became extinct on the mainland 3000 years ago as a consequence of hunting by dingoes. However, extensive dingo culls to protect livestock have now shifted the ecological balance, enabling invasive predators to wreak havoc with native mammals and igniting discussions about bringing the devil back to the mainland.

Ecologists from The University of NSW have now assessed the impact of reintroducing Tasmanian devils to forest ecosystems in south-eastern parts of NSW. “There are large areas where the dingo is gone, and we need a predator who can suppress fox numbers,” says PhD candidate Daniel Hunter. “The devil is the obvious answer. It doesn’t pose as serious a risk to livestock, and it has played a major role in stopping foxes from establishing a foothold in Tasmania.”

The study found that the devil could restore important ecosystem functions previously performed by dingoes. Furthermore, reintroduction could help ensure the long-term survival of the devil, which has seen massive population decline in Tasmania due to devil facial tumour disease.

The team reviewed previous studies to understand more about the ecological impacts of dingoes, devils and foxes, and then applied this information to their models, which tried to predict how a range of ecosystems would respond to the presence of devils.

Their results suggest that reintroducing devils would result in fewer foxes and feral cats, as well as grazing herbivores such as wallabies, which remove vegetation that helps smaller animals hide from predators.

“We suspect that they help control the fox and cat populations by directly attacking them and their young,” says co-author A/Prof Mike Letnic. “There is very good evidence from Tasmania that cats modify their movements and numbers are lower where there are healthy devil populations.”

The research also suggests there would be benefits for small and medium-sized animals, such as bandicoots and ringtail possums, as well low-lying vegetation. However, threatened species vulnerable to fox predation benefited little from devil introduction.

“Devils aren’t a silver bullet, but we think that they could do a lot of good on the mainland, and this study indicates that a monitored process of reintroduction could actually work,” Letnic says.