You may have heard that Australia has one of the worst records for animal extinctions in the world.
The most recent State of the Environment report (2021) points out that we have lost more mammal species than any other continent and have one of the highest rates of species decline overall.
When colonisers arrived, some animals were wiped out by human hunting, others by the introduction of foxes and cats.
But many did not become extinct Australia-wide, and still exist in some parts of the country.
These remaining populations are at the heart of the idea of 'rewilding', which has been carried out for several years in places including the United States and Europe.
By preserving large areas of wilderness big enough for carnivores, such as wolves and bears, animals have been able to repopulate and fulfil their ecological functions.
As University of Tasmania researcher Tristan Derham explains, in Australia, rewilding is a newer phenomenon.
"It's come to mean reintroducing animals to do ecological restoration work with us," he said.
"A lot of people think about ecological restoration in terms of planting trees, creating the right kind of habitat and vegetation, and then animals will find their way to it.
"But what we're realising now for Australian ecosystems, there are certain kinds of animals that really promote other ecosystem processes, including seedling success."
Rewilding around the country
Several rewilding projects are currently taking place across Australia, and some have already found success.
See some of the projects happening in your state or territory:
Many of these projects focus on smaller marsupials.
Small digging animals are often referred to as "soil engineers" by ecologists, because of how efficient they are at boosting ecological growth.
"Digging animals like bettongs, potoroos and bandicoots, they'll dig tiny little holes in the ground, when they're looking for things like truffles," Dr Derham said.
"What happens is those little divots in the soil will collect leaf litter, they'll collect moisture, and they'll collect seeds, and they'll become a tiny little microhabitat."
Brush-tail bettongs have been successfully reintroduced on South Australia's Yorke Peninsula — after being extinct in the area for more than a century — as part of the Marna Banggara project.
Project organisers hope to reintroduce more species.
Narungga Nation Aboriginal Corporation business manager Garry Goldsmith said reintroducing native animals held cultural as well as ecological significance.
"There's definitely that revived sense of both the animal doing its job, the prevalence and presence of it throughout the park, and, obviously, that connection for the Narungga people, to see part of what was originally there," Mr Goldsmith said.
"We had animals come in [to South Australia] from Western Australia, and working with those local communities has been great."
Some Aboriginal and First Nations people have concerns about the term rewilding because it implies the land had not been cared for by anyone.
"There needs to be the acknowledgement of our connection to country, which we have been caring for, for thousands of years," he said.
"That's why it's so important to include First Nations people in these projects. We know the ecosystem and how it has changed over time.
"I think if there's some truth behind why we are reintroducing this species, then that would sit comfortably with me because the truth to be told is that colonisation has impacted on native species, whether it be flora or fauna, and also, most importantly, our people."
Introduced animals can make the process tough
As every ecosystem is different, rewilding produces varying levels of success.
Animals that may have once thrived in an environment may struggle when reintroduced, due to being hunted by wild cats and foxes.
Attempts to return eastern quolls to the NSW coast resulted in them dying out again.
Rob Brewster from WWF Australia said while not every rewilding attempt was successful, the potential benefits outweighed the costs.
"We're talking about animals that are culturally significant, to Indigenous Australians, and to Australians more broadly.
"Animals like the koala and the platypus are really important to our country."
Tasmania could hold key to future rewilding success
Mr Brewster said Tasmania was a "vital location" to help with rewilding efforts as the island was home to "many species that have gone missing from the mainland".
"So we really need to make sure that Tasmania remains as intact and as pristine as it is," he said.
"On an island, you can more easily remove feral cat populations and bring back a whole suite of important native species.
"We'll be working very hard in Tasmania over the next few years to bolster the population of eastern quolls, so they don't go the same way they did on the mainland."
Mr Brewster said there was still an issue in many parts of Australia managing animals that have caused extinctions — mainly foxes and cats.
"We don't yet have a good grasp on effectively managing those species on a wide scale, so that's certainly the challenge for rewilding on mainland Australia right now.
"We might need to start thinking outside of the box," he said.
Some ecologists said the solution could be found in rewilding predators to help manage feral cat and fox populations.
Bring the devil to Victoria?
University of Tasmania ecology professor Chris Johnson said reintroducing Tasmanian devils to Victoria should be considered.
"There's good evidence that show Tasmanian devils have helped control populations of cats on Maria Island," Dr Johnson said.
"They also helped to control the population of possums on the island, where the overpopulation caused them to become a predator."
Tasmanian devils were introduced to Maria island in 2012 as an 'insurance population' when devil facial tumour disease (DFTD) was decimating the species.
But the introduction of devils came at a cost.
Penguins and local birds were decimated, with penguins believed to now be extinct on the island.
Professor Johnson said when Tasmanian devils were placed back into ecosystems they once belonged to, they could be effective in managing other species.
The Maria Island population of Tasmanian devils is free of the devil facial tumour disease, and Professor Johnson said moving these to the mainland could boost their population.
"And in areas where species are threatened by cats and foxes, like with the eastern quoll on the mainland, we could consider using devils to help hunt these predators, which would in turn help the quolls."
Removing dingoes creates 'long chain of ecological impacts'
Dr Johnson said the way dingo populations are controlled in Australia could also be changed.
"Dingoes are often viewed as pests, but they're very efficient in controlling populations of kangaroos, as well as reducing fox numbers," he said.
"Kangaroos overgraze when they're uncontrolled and cause denuding desertification — meaning they reduce perennial grasses."
Dr Johnson said that could affect a wide range of species, as well as farmers who have land for grazing stock.
"When you've got control of foxes, there are also healthier populations of native rodents, who have their own ecological benefits," he said.
"When we hunt and remove dingoes from ecosystems, we create a long chain of ecological impacts.
He said dingoes also held cultural significance in many Aboriginal communities.
"The debate about dingoes typically ignores the fact that they're extremely significant animals, that historically they've been very important in traditional Aboriginal society, and they're still highly valued.
"Actually asking and involving Indigenous people in this would be a really important step."
Dr Johnson said potential projects like rewilding dingoes that were still a long way off.
"We need to change community attitudes first if we want rewilding to really take off."
