Martu desert country, north-east of Wiluna in Western Australia, is green right now. "We had a big rain in this area," says Yvonne Ashwin, Martu woman and coordinator of the Martu rangers, who care for this country. Normally the desert is dry, the red soil tufted with spinifex and the brown bursts of mulga trees. But now the rains have been, and everything is lush and sprouting. The thriving desert life that usually conceals itself from the sun, heat and untrained eye is on full show; birds, insects, reptiles, mammals, flowering plants and trees.
Ashwin and her team of Indigenous rangers work across the vast Matuwa Kurrara Kurrara Indigenous protected area (IPA); nearly 570,000 hectares (1.4m acres) of native title-determined country of the Tarlka Matuwa Piarku Aboriginal Corporation. They crisscross its scorching hot landscape on car and foot, looking for tracks of bilbies and cats, scouting for clumps of invasive buffel grass and boxing glove cactus that they can dig out and burn, clearing road tracks of trees and old fencing wire, and using fire to tend to the landscape as their ancestors have done for tens of thousands of years.
About 2,500km away in the red dirt of the Sturt desert, where New South Wales, Queensland and South Australia meet, ecologists Dr Rebecca West and Dr Reece Pedler are checking the traps inside a heavily fenced 20 sq km enclosure. They're not hunting for cats or foxes among the cane grass, wattle and saltbush but for golden bandicoots, bilbies and crest-tailed mulgara.
This is the Wild Deserts project; two enclosures where feral predators such as cats and foxes, and invasive pests such as rabbits, have been completely eradicated to give these tiny mammals, which are tap-dancing on the edge of extinction, a chance at survival. Small numbers of them are being gradually reintroduced into this now-safe desert haven, and left to get on with the important business of growing their populations.
[Rewilding] is giving nature the space and the time - critically - to dictate its own ecological trajectories
These two very different scenarios, in their own ways, could be considered rewilding. Both represent efforts at restoring lost species to landscapes they once thrived in before colonisation brought with it new and deadly predators, invasive plants that outcompeted native species, and stock with unfamiliar hard hooves and hungry appetites.
"[Rewilding] is giving nature the space and the time - critically - to dictate its own ecological trajectories," says Dr Steve Carver, geographer at the University of Leeds in England, and joint chair of the International Union for the Conservation of Nature's CEM Task Force on Rewilding. At its theoretical simplest, it's about letting nature be what it wants to be "in the absence of human intervention", although he adds that the reality often involves initial human intervention to catalyse the process.
It is a hot topic in conservation but rewilding comes with some problematic assumptions about what wild means, and how humans - especially First Nations people - fit into the picture.
Rewilding as a concept is imbued with western colonial frontier ideas of wilderness and wildness. It's also a term that originated in the heavily altered ecosystems of Europe and North America, where there is very little left that could be considered wild. Rewilding projects there have included removing cattle and sheep and reintroducing the grey wolf to the American West; tree planting and reintroducing beavers in Cornwall in England; and reintroducing wild bison to Kent. Humans play an important role as the means to an end - the ones making the rewilding happen - but they do not feature as an ongoing presence.
It implies . that there's no wild left in the deserts, which is a bit of a misnomer for the Australian deserts
This is why the term "rewilding" can be controversial, particularly for the deserts of Australia, many of which are relatively untouched by the forces that have so disturbed more heavily populated regions. "To me, it implies straight away that there's no wild left in the deserts, which I think is a bit of a misnomer for the Australian deserts," says Gareth Catt, deserts project manager with the Indigenous Desert Alliance. While it has suffered the impacts of colonisation and climate change, it remains less altered than other landscapes, and more alive than most imagine. "It's a large, intact landscape; one of the last great intact landscapes globally."
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But it's also a landscape that has been shaped by Indigenous Australians. "The Australian context is really different because its deserts are still peopled," says wildlife ecologist Professor Sarah Legge, from the Australian National University in Canberra. "There's people living there and they're managed; they have been managed for 60,000 years."
Deserts are often perceived as barren and empty spaces, a landscape hostile to life. This has meant they have received far less attention than they deserve in the global biodiversity crisis discourse, says conservationist John Watkin, CEO of the Sahara Conservation Foundation, who is based in Saint-Maur-des-Fossés, France.
"We refer to the Sahara and the bordering Sahelo-Saharan lands as orphans, conservation orphans," Watkin says. When Conservation International first came out with its list of biodiversity hotspots that are threatened and in need of attention, not one desert biome was included in the list. "It's equivalent to the seabed - it's not happening if you don't see it happening."
In fact, deserts have historicallythrived with life, and life that is spectacularly adapted to extremes of temperature, to limited resources, and to sporadic and unpredictable rainfall. It is used to living on a knife-edge. However Australian desert life is not adapted to wily voracious predators such as cats and foxes, and to the damage done by hard-hoofed grazing animals that did not exist on the continent before colonisation. And it is also vulnerable to extreme bushfires and prolonged drought. All these threats are contributing to local and more widespread extinctions of native desert species, and it's not yet clear what their loss will lead to.
In Australia, where 70% of the landmass is semi-arid or arid land, small fossorial mammals - mammals that dig and burrow - are a cornerstone of a vibrant desert ecosystem. "They're hugely important for that whole side of what we call soil turnover, nutrient cycling and seedling germination," Rebecca West says.
Animals such as bilbies and bettongs burrow into the ground, bringing up nutrients and creating new subterranean habitats for other species, both fauna and flora.
However these tiny mammals are also the most vulnerable to feral predators such as cats, foxes and pigs. "We've got the worst extinction record in what are called the critical weight range mammals - I like to refer to them as basically bite-sized animals," says Prof Richard Kingsford, project leader of Wild Deserts and director of the Centre for Ecosystem Science at UNSW Sydney. "The biggest problem [for deserts] is really related to losing that huge part of the trophic web, the middle part of the food web."
It's the reason that the Wild Deserts initiative exists; to fence off two predator-free, cattle-free spaces in the Sturt desert and gradually reintroduce seven locally extinct mammals.
There are similar projects dotted around Australia. At Mallee Cliffs national park in western NSW, the Australian Wildlife Conservancy manages a 58,000-hectare (143,00-acre) area fenced off against predators, into which they are reintroducing similar mammal species to Wild Deserts. The Arid Recovery reserve in the northern desert of South Australia has a 123 sq km fenced reserve with the same goal. Matuwa Kurrara Kurrara IPA also has a fenced area to protect the most vulnerable and rare mammals, such as the burrowing bettong and the mala, or rufous hare-wallaby.
These island initiatives work, Legge says. "If you built a fenced area well and there's no breaches, the success rate is very high of a translocation," she says. For fenced havens, it's about 80% to 90%. For actual islands, she says the success rate is even higher - up to 90%.
But those successes don't come cheap: fencing is expensive and requires constant maintenance and checking. It means these predator-free spaces will always be limited by cost and logistics. "These havens are absolutely critical to stopping extinction," Legge says. "But they still represent way less than 1% of the former distributions for most of these species."
We're also not going to be able to control and get rid of every single cat in Australia
They also create problems of their own. Ironically, by protecting small mammals from cats and foxes, these fenced enclosures effectively lull them into a false sense of security, and they lose those survival traits and instincts that they need to avoid predators. The limited size of havens also means that they can only sustain relatively small populations of animals. "If we have a species that was once spread right across the continent and now it's only in two or three tiny spots, then we're losing all the genetic adaptations that different populations had in different places," Legge says.
Fenced enclosures are not the endgame, and no one - not even the scientists who work in these havens - is under the illusion that these carefully controlled havens are a long-term solution to Australia's extinction crisis. "We're not going to keep building tiny fences everywhere and fence off everything," West says. "We're also not going to be able to control and get rid of every single cat in Australia, with the tools that we have at the moment."
It's a dilemma that is unique to Australia. Other regions are generally reintroducing much larger animals, such as bison, scimitar-horned oryx or grey wolves, whose main predator threats have been humans. Keeping humans away from these protected areas is a far simpler prospect than keeping cats or foxes away from their smaller prey.
"What we're trying to focus on is how do we deal with that threat outside the fences," Kingsford says. Wild Deserts has a separate "training zone", which is fenced enough to keep out larger animals such as cattle and camels but not foxes, cats, rabbits and kangaroos.
Over in Matuwa Kurrara Kurrara and many other Indigenous protected areas, there are few fences. Instead, there are dedicated groups of Indigenous rangers, such as Ashwin, and traditional owners who spend time and resources caring for and connecting with country, trapping feral species, removing invasive weeds and looking after the native species that have survived these challenges.
The notion of rewilding that excludes an ongoing human presence doesn't work for Australia's deserts, says Dr Dorian Moro, a wildlife ecologist and environment manager working with the Wiluna Martu rangers. "Rewilding almost presumes that you are sitting back and letting the country take over and return to what it once was," he says. But Australia's deserts have had people present and actively managing them for up to 60,000 years. "The area had, and always has, Indigenous people on it, and these Indigenous people inherently change landscapes."
The results of the rangers' work speak for themselves. Numbers of golden bandicoot in the area have rebounded, so much so that several were translocated halfway across the country to the Wild Deserts project, accompanied by some of the Wiluna Martu rangers.
"That's a proud moment for them, to be custodians of healthy country where others wish to come along and say, 'hey, you've got a lot of animals, can we use some to repopulate elsewhere in Australia?,'" Moro says.
It illustrates how these two approaches can complement each other. A similar collaboration in 2017 helped save the mala from extinction on the Australian mainland. The Newhaven Warlpiri rangers worked with the Australian Wildlife Conservancy and Northern Territory government to evacuate a small group of the wallaby, clinging to existence after a wildfire devastated one of the last remaining mainland populations in the Watarrka national park. They were relocated to a predator-free fenced haven, and the hope is once their numbers grow they will be able to repopulate the desert area.
These partnerships are still a new experience, Catt says. "We haven't figured out how those two things relate properly, and I think this is a part of a maturing of the conservation sector and the Indigenous land management sectors."
The question for Australia is how these two approaches to restoring desert landscapes can work together to achieve the best outcomes. Fenced areas alone are not enough, Catt says.
The goal, he says, is not a preservation situation; isolated, guarded islands of a chosen few species. It is diverse populations of native species, thriving within complex and healthy ecosystems that span the length and breadth of Australia's dry centre. This, he says, is the "end game".