Imma Perfetto
Cosmos science journalist
Welcome news for the nature conservationists – 2 native Australian animals are thriving in the Ikara-Flinders Ranges National Park in South Australia – more than a decade after they were first reintroduced and despite enduring one of the harshest and driest summers in recent years,
According to recent trapping efforts by National Parks and Wildlife Service (NPWS) rangers and volunteers, 135 western quolls and 30 brush-tailed possums were caught, scanned and released over 5 nights in late March.
The western quoll (Dasyurus geoffroii) is a carnivorous marsupial and nocturnal predator that was once found across 70% of Australia. However, due to a combination of invasive predators and extensive land clearing, it disappeared from everywhere but southeastern Western Australia.
Dr David Peacock, senior researcher in Pest Animal Management at the University of Adelaide’s Davies Livestock Research Centre, told Cosmos he first presented what he describes as the “crazy idea” of reintroducing western quolls to SA in 2008 “…primarily as a predator of rabbits, because they’re our number one pest animal out there.
“In the Iberian Peninsula where they’re from, Spain and Portugal, like 25-30 animals feed on rabbit. They are critically important. Over here, it’s the complete opposite.”
“We now know that our endemic plants, which store carbon and form habitat for birds and shade for stock animals … cannot recruit when there is more than, say, 1-2 rabbits a hectare. And you can easily exceed that just in warrens per hectare, let alone rabbits per hectare.
“If we don’t get rabbits down below these thresholds, with whatever means we have available, then we are going to be constantly losing the environment.
“That’s where the idea began, and it just grew a life its own.”
The Department of Environment and Water’s (DEW) Bounceback program, in partnership with the Foundation for Australia’s Most Endangered Species (FAME), reintroduced western quolls in 2014 and brush-tailed possums in 2015.
Peacock, who is no longer involved with the project, says the big issue in the early days was cats.
“In 2014-2016, we just weren’t getting very far. The quolls should have been having 6 babies per female, and half of those would be female, and they should be having 6 babies in their first year.
“We weren’t getting anywhere until the Department agreed to start distributing West Australia’s Eradicat sausage bait under experimental permit.
“And that was a game changer. From then on, the quolls became much more abundant,
“Things started to kick off in 2017 and every year now, basically, they break a record. It’s just been phenomenal.”
The latest trapping efforts indicate that a healthy and viable population of quolls persists in Ikara-Flinders Ranges National Park, despite a harsh and dry summer. Of the 135 western quolls captured, 81 were new to the monitoring team.
He says the recent numbers are “what we dreamed of at the beginning of the project”. They are only possible due to an integrated pest management approach which targets feral cats, foxes, and rabbits.
“You can’t just do one thing, like throw quolls in the system, and I think it’s going to fix it. It’s never meant to be a silver bullet … It’s just simply one part of us trying to rebuild an ecosystem back to function better than it was, and close maybe to what it used to be,” says Peacock.
“But you just can’t even get close to that if you allow foxes and cats to be in the system.”
As part of the Bounceback conservation program, DEW and FAME have established 3 “safer havens” for endangered species in South Australia’s Flinders Ranges, Gawler Ranges, and Gammon Ranges.
“The safer havens are unfenced areas, each about 500km2, where feral animals are substantially reduced to allow reintroduced native animals to thrive,” says FAME Chief Executive Tracy McNamara.
“It’s a massive infrastructure cost to put up a physical fence and a massive cost to maintain it. So, we decided to do it through baiting. It’s a chemical fence,” says Peacock.
“With the cat management with the sausage baits … and with the fox baiting that happens about 3-4 times a year now, you can’t find a fox on the park … and the cats have been significantly controlled.
“Now there are rock wallabies in places where I never saw them in 1995-96 when I lived and worked there. And then we got possums back, we’ve got quolls back.
“Until we find a biological solution to the fox and the cat we have to have a fence – either a physical fence, like up at Arid Recovery, or a chemical fence.
“You take that fence away by a stroke of a pen or a budget cut and the foxes [and cats] will come in tomorrow. And over the over the next months and years, we’ll go right back to where we were in the 80s.”
