Saving Australia’s native mammals from invasive predators

During 2021’s SCINEMA International Science Film Festival, viewers went on an adventure into outback South Australia with two of the nation’s leading ecologists – Professor Katherine Moseby and Dr John Read – in the film Recovery Team: Saving Species.

The pair, who are professional and life partners with more than 50 years of combined experience in ecological management and research, ventured into the outback to save some of the rarest native Australian animals.

We caught back up with them to see where these efforts have progressed, and to find out what’s ahead for them in helping our embattled native species to survive and thrive.

Australian mammal extinction rates are the worst in the world

Species that have thrived in the Australian landscape for thousands of years have been disappearing largely continuously since Australia’s European colonisation, and nowhere have mammals fared worse than in the arid zone.

It’s a scary reality, but Australia has the worst mammal extinction rate in the world. At present, there are 39 mammals species listed as extinct, and a worrying nine that are critically endangered.

According to Moseby, research fellow at the University of New South Wales with over 25 years’ experience in arid-zone ecology and threatened-species management, this is due to a range of ongoing threats.

“Europeans altered the landscape when they arrived in Australia by extensively clearing native vegetation for agriculture,” says Moseby.

“In the arid zone, where we still retain much of our native vegetation, the landscape has been degraded through the introduction of rabbits, camels and goats and overgrazing by domestic stock.

“Feral cats and foxes were also introduced, which preyed on our native species and have directly contributed to mass extinctions of animals weighing between 35 grams and 5.5 kilograms.”

Feral cats are a particular threat

Feral cats represent the greatest threat to many native species, endangering the survival of more than 100 species and implicated in the extinctions of at least 27 native mammals. But it’s particularly challenging to try to effectively manage their populations.

“Feral cats are notoriously difficult to control with baits or baited traps because they are primarily hunters rather than scavengers and [are] seldom attracted to baits when prey are abundant,” says Read, adjunct senior lecturer in ecology and evolutionary biology at the University of Adelaide, and published non-fiction author.

To try to improve these efforts, Read and Moseby’s consultancy company, Ecological Horizons, developed and patented a novel, humane and automated tool to help control and reduce the number of feral cats and foxes.

Called Felixers, the machine uses sensors to detect feral cats and foxes – distinguishing them from wildlife and humans – spraying targets with a measured dose of the toxic 1080 gel.

“Felixers utilise cat’s fastidiousness with cleanliness to deliver toxin via oral grooming,” says Read.

1080 (sodium fluoroacetate) is a naturally occurring toxin found in more than 30 species of native Australian plants. Native wildlife has shared its environment with such plants for thousands of years and, as a result, developed a natural tolerance to it, whereas introduced mammals are much more sensitive.

Since the film’s release, Felixers are manufactured and managed by Thylation, a not-for-profit company that Read – its CEO – founded to commercialise conservation innovations.

Felixers have been deployed in multiple case studies across Australia to test their performance in different environments. The results are promising, with target specificity meaning that most native carnivores are too small – and adult dingoes too tall – to activate it.

But Australia has so many ferals cats – an estimated 6.3 million – meaning the issue needs to be tackled on multiple fronts.

Can native species and introduced predators co-exist?

In addition to these efforts, Read and Moseby have helped set up several exclosures where invasive predators have been completely removed.

These include the 123-square-kilometre fenced Arid Recovery Reserve in northern South Australia, where five native species have been reintroduced; a four-kilometre-long fence in the APY Lands known as the Pintji, which provides a safe haven for Warru (black-footed rock wallabies); Wild Deserts, a reintroduction and restoration project in Sturt National Park in NSW in collaboration with UNSW and NSW DPIE; and a 40-square-kilometre fenced area within Secret Rocks, Read and Moseby’s private nature reserve on the Eyre Peninsula.

While these areas have brought success in the breeding of native species, it is time intensive and costly to build and maintain the fences. The challenge is to replicate this success outside of enclosed areas.

“Australia’s native mammals did not co-evolve with foxes and cats and so have not evolved appropriate or effective avoidance and escape strategies,” says Moseby.

“After decades of failed reintroduction attempts outside of fenced reserves and islands, even with intensive feral cat and fox control (baiting, trapping, shooting etc), we thought it was time to try and address the issue from the prey perspective.”

Their idea was to expose naive prey – animals that had never encountered predators within their enclosed areas – to low numbers of feral cats to try to reintroduce anti-predator behaviour into the population.

“Animals learn quickly, and selection for some traits can occur after only a few generations, so we were interested to see if we could accelerate natural selection for anti-predator traits,” says Moseby

 So… did it work?

It did, to an extent.

“We found increased survival in species such as bilbies after exposure to cats,” says Moseby. “But although we found changes in the bettong’s physical and behavioral traits – increased vigilance, increased escape behavior, increased wariness, longer hind feet – we have not yet seen this lead to increased survival in this species.

“This could be due to the longer period of isolation, as burrowing bettongs became extinct on the mainland and the only populations we have left are on islands where they have been isolated from all mammalian predators for thousands of years.

“So, we are now trialing exposing bettongs to native predators first, to see if we can use these as a stepping stone.”

They’re doing this with western quolls, a marsupial predator with which bettongs co-evolved, which might provoke a stronger response.

“We are conducting trials with quolls as they have a shared evolutionary history, which suggests they should be able to regain lost anti-predator traits more quickly,” says Moseby.

What’s next?

Looking to the future, the researchers plan to continue their efforts at Secret Rocks, South Australia’s largest privately managed nature reserve.

“We plan to reintroduce brush-tailed phascogales there this year as well as numbats,” says Moseby. “We have threatened populations of malleefowl, Shark Bay barred bandicoots, and sandhill dunnarts there as well that we are protecting through fox and goat control, fire management and fencing.”

Read adds that a paradigm shift is also required in the way kangaroos are managed, as outlined in a special edition of Ecological Management and Restoration that he edited last year.

“Ironically, the broadscale control of rabbits through biological control has exposed overabundant kangaroos as one of the major environmental and animal welfare risks throughout southern Australia where dingoes are controlled or excluded,” he says.

The ecologists are determined to continue their important research and help redress major environmental threats.

“Research that is both collaborative and helps engage and inspire others, including Indigenous communities, farmers and miners, to embrace proactive conservation measures are especially interesting,” says Read.

Moseby adds that she gets excited “if my research leads to improved outcomes for threatened species or changes the way people think or how organisations manage their land.

“At the end of the day, research outcomes need to be adopted and implemented if we are to change the trajectories of our threatened species and communities.”

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You can watch Recovery Team: Saving Species here.