Australia is picking winners and losers by failing to fund the recovery of all the plants and animals on the country's threatened species list, scientists have warned.

Key points: Scientists say Australian governments are spending one tenth of what is needed on threatened species.

Scientists say Australian governments are spending one tenth of what is needed on threatened species. Three animal species have become extinct in Australia in the past decade.

Three animal species have become extinct in Australia in the past decade. Scientists say they often have to rely on crowdfunding and volunteers for conservation work.

Australia has the highest rate of mammal extinctions in the world and is the fourth worst for animal extinctions globally.

There are more than 1,800 plants and animals on Australia's threatened species list, including more than 500 animals.

By analysing state and federal budgets, scientists from the government-funded Threatened Species Recovery Hub research group have found Australian governments are spending a fraction of what is needed to conserve all the wildlife on the list.

Research hub director Professor Brendan Wintle said Australia was already "picking winners and losers".

"We're currently spending about a tenth of what we need to spend," he said.

"By not funding all species to the level that's required to keep them in the game, we're essentially allowing quite a lot of species to fail."

Three extinctions in the last decade

In the last decade alone a bat, a skink and a rat have become extinct in Australia.

The Morrison Government's new Environment Minister, Sussan Ley, told Four Corners the Government is "picking where we can make a difference".

"It's not about waving a cheque book at the levels of threatened species, it's about sensible funding, which we do," she said.

"I don't want to see any more species go extinct while I'm in this role."

But Ms Ley said she could not guarantee more species would not become extinct under her watch.

The Bramble Cay melomys, which was endemic to a tiny island in the Torres Strait, has been declared extinct. ( Supplied )

In February this year, Australia lost the Bramble Cay melomys, a small brown rat found on a tiny bank of sand in the Torres Strait.

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That was despite the previous Environment Minister Greg Hunt "drawing a line in the sand" four years ago saying: "on our watch, in our time, no more species extinction."

The Federal Government says it has invested more than $400 million in threatened species recovery efforts, but Professor Wintle said analysis showed targeted spending by the federal and state governments totalled only about $121 million.

"Unfortunately, our legislation falls down in the sense that it doesn't mandate spending of a sufficient magnitude to actually avoid extinctions," he said.

Professor Wintle said a third of Australia's threatened species were not being monitored.

"We could be losing them and we wouldn't know," he said.

"If we want it to stop, we're going to have to do a lot more than we're currently doing."

Conservationists have relied on crowdfunding to try and save the swift parrot. ( Chris Tzaros )

Relying on crowdfunding, volunteers

Even for the animals that do attract some government funding, a lot of the recovery work falls to members of the public and non-government groups.

Dejan Stojanovic, who studies the critically endangered swift parrot in Tasmania, has at times had to rely on donations for his conservation work.

"Threatened species conservation is so poorly funded in this country that we've quite regularly had to turn to crowdfunding to fund really basic aspects of our research," he said.

Steve Meacher, a member of the Friends of Leadbeater's possum group of volunteers in Victoria, said he and others regularly headed out to the cold, wet forests of the central highlands looking for the species so that logging-free zones could be established around colonies.

"A lot of this work isn't being done by government agencies so if volunteers like us weren't doing it, it just wouldn't be done and the animals would be going extinct," he said.

The Leadbeater's possum is now critically endangered. ( Facebook )

A cute and cuddly success story?

One potential success story is the eastern quoll, which became extinct on the mainland in the 1960s but persisted in Tasmania.

The Federal Government has pledged $1.5 million to help the species. There are also efforts to try to reintroduce it to mainland Australia.

The eastern quoll is a cute, spotted, cat-sized mammal and Charles Darwin University conservation biologist John Woinarski said if it survived, it would be an example of what success could look like.

"But this also exemplifies the fact that we do care much more and are much more successful with the charismatic species," he said.

The Christmas Island skink which is now extinct. ( Supplied: Dr Hal Cogger )

A threatened species expert with more than three decades of experience, Professor Woinarski saw the last living Christmas Island Forest Skink, named Gump, before it died in captivity in 2014.

"Haunting," is how he describes seeing the animal, knowing its death would mark the end of an entire species.

Professor Woinarski said the skink was largely driven to extinction because of the introduction of a snake from Asia that ate native reptiles and its decline was exacerbated by years of mining on Christmas Island.

"That extinction could well have been prevented if we'd done more about it," he said.

"It was easy to remedy, we could have brought more of the individuals into captivity before the crash in the population occurred, we could have maintained that species.

"We are a prosperous society, we are a caring society, we have a wonderful nature, we shouldn't be allowing such species to slip into extinction without us actually raising a finger to do anything about it," he said.

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