Managing threatened species and predators on Astrebla Downs

A concerted wild dog/dingo and feral cat management program, and favourable conditions in 2019, has resulted in a record number of bilbies and kowaris in the Astrebla Downs National Park.

The threatened species were filmed by Queensland’s Department of Environment and Science senior ecologist, John Augusteyn, on a trip to the park in June 2021 as part of a monitoring program using thermal cameras, drones, fixed-wing aircraft and acoustic recorders.

“Park rangers have been working hard to reduce feral cat and wild dog numbers on the National Park and have removed more than 3000 cats and more than 50 wild dogs over the past 10 years,” Mr Augusteyn said.

“The high numbers of bilbies and kowaris on Astrebla Downs National Park is a strong testament to the value of the predator control efforts.”

Department of Environment and Science staff have also recorded bilby burrows across vast areas of south-west Queensland in both protected areas and neighbouring grazing land.

“The aim of the survey work was to develop robust methods that can be used to monitor bilbies and kowaris across the landscape both now and into the future,” Mr Augusteyn said.

Wild dogs were controlled over some of this as part of the Barcoo Shire aerial baiting program.

In research published in September 2020, Augusteyn et al. reported on the diet of wild dogs from scats collected over seven years from Astrebla Downs National Park.

Animal remains such as hair and bones in the scats were examined to determine what native fauna the wild dogs were eating.

The results revealed a diverse range of native species were eaten by wild dogs but bilbies were heavily preyed upon by wild dogs at Astrebla Downs.

“Bilbies were consumed by wild dogs at a higher rate than most other species and contributed to an average of 84 per cent of prey volume within scats,” Mr Augusteyn said.

“Rabbits were only detected in winter-spring 2018 when five scats contained less than 20 per cent rabbit. “

Patchy rainfall in 2016 helped to boost both rodent and bilby populations but the boom was short lived and the density of bilbies declined by up to 96 per cent by 2018.

The decline in bilby numbers coincided with increased predation by wild dogs.

“The proportion of dog scats containing bilby increased in winter 2016 to 70 per cent and peaked at 85 per cent in winter-spring 2018,” Mr Augusteyn said.

Previous studies have suggested that predators had their strongest impacts on native animals in the one to two years following high rainfall and considered this time the most critical for wildlife managers.

“We found the predators shifted their preferred prey over a period of about one week,” Mr Augusteyn said.

“Therefore, we recommend for major booms, like native rodent plagues, control starts before predator numbers build and continues until predator populations are reduced to the point where they are not impacting threatened species.

“Otherwise, it is difficult to have staff on the ground ready to start control the moment the predators shift their prey preference from the rats to the threatened species.

“It is also difficult to control the predators when they are at their peak and getting in early reduces the chance of their numbers building to plague proportions.

“Predator control is also recommended during droughts and periods of low resource availability, particularly if they immediately follow a resource pulse.

“The capacity of the Astrebla population to recover from a major predation event also highlights the resilience of the population and it is possible to maintain a healthy one without having to resort to expensive predator-proof fences.”

National Wild Dog Management Coordinator Greg Mifsud said the work undertaken on Astrebla Downs National Park highlighted the fact that as a generalist predator, wild dogs and dingoes can severely impact rare and threatened species under certain conditions.

This is reflected by the fact wild dog/dingo predation is listed as a known or potential risk to at least 14 endangered or vulnerable native mammal, reptile and bird species under the Environmental Protection and Biodiversity Act 1999.

A number of long-term studies from a range of locations across Australia have demonstrated wild dogs/dingoes have little impact on feral cat and fox abundance.

A recent publication from Eammon Wooster, of University of Technology Sydney, showed fox abundance and activity was at its highest in the presence of uncontrolled dingoes on a cattle property in arid rangelands of South Australia.

Predation pressure from these introduced predators including wild dogs and dingoes on already threatened populations of native animals like the bilbies can hamper their recovery or lead to local extinction events.

“The approach taken by Queensland Parks and Wildlife Service reflects the principles of the National Wild Dog Action Plan where management is implemented to mitigate the negative impacts on valuable assets, which in this case is rare and threatened fauna,” Mr Mifsud said.

View vision of the rare kowari

Further reading on the threat wild dogs pose to bilbies at Astrebla Downs National Park.

More research on the impact of dingoes on native fauna.