In Australia in recent decades, the bilby, the bettong, or rat kangaroo, the brush-tailed possum and other medium-sized mammals all disappeared from the Western Desert. It was a mystery: Typically bigger animals vanish first — often only after people show up.
But ask the people who lived in this desert for 48,000 years what happened and many will tell you: They left.
“A lot of Martu people say that if there’s no people out in the country, then all the animals become absent. When the people and animals are absent, then the country becomes sick or unwell. There’s no balance there,” said Curtis Taylor, a filmmaker and young leader of the Martu community.
With all the damage done to the planet’s environment in recent centuries, it’s easy for some to think of humans as the planet’s great destroyers. But in a study published Friday in Human Ecology, scientists critique this notion of a human-free wilderness. By examining how an Aboriginal Australian community have shaped their land through traditional hunting, they present an example where it’s not all bad to have humans around.
“We can still see the ways that the Martu look after country,” said Stefani Crabtree, an archaeologist, ethnographer and an author of the study.
Their story of stewardship, Dr. Crabtree and colleagues say, could be applicable in other environments threatened by degradation.
The Martu are defined under Australian law as the traditional owners of more than 52,000 square miles of land in the Great and Little Sandy Deserts. They hunt with fire, burning small patches of vegetation and returning after the flames subside to capture goannas and other small prey. But in the 1930s, they started trickling out of the desert into nearby missionary settlements and cattle ranches. By the 1960s, after drought and the British and Australian governments started a nuclear testing program, nearly all traditional hunters had left to find their families or were taken from the Western Desert.
“It was in that time that you get this wave of extinctions,” said Doug Bird, an author of the study and an anthropologist at Penn State University who has been working with the Martu to better understand how they care for their land. It seemed paradoxical to him: How could taking hunters out of the desert harm it?
In the 1980s, mining and exploration threatened their homeland, so the Martu returned to reclaim it and resume their hunting traditions. The researchers interviewed the community and observed their foraging strategies and reconstructed food webs in the desert before the Martu left, and after they returned. From these models, they simulated how removing people affected other parts of the desert food chain — like kangaroos eating bush tomatoes, or birds eating rodents.
“When people started to come back and going hunting again and looking after their country, you could see this resurgence of animals coming back to parts that they had been absent for a long time,” Mr. Taylor said.
The small hunting fires were vital for sustaining wild species. Without Martu people starting them year-round, seasonal lightning fires raged. Invasive predators thrived and mammals needing to travel long distances for food or water got hit hard. Even the goannas they hunted struggled without the Martu.
“The thing about fires is that they’re creating this patchy mosaic of really diverse vegetation,” said Rebecca Bliege Bird, an anthropologist also at Penn State and co-author.
Chunks of the landscape are always at different stages of recovery, with different vegetation. Spinifex, a grass that otherwise lives for decades and crowds everything else out, is replaced by other plants like bush tomatoes, an important food and water source. And many animals have more places to get food, shelter or protection from predators. After a few years, spinifex returns, and the cycle continues.
“In some ways, it’s a pretty straightforward relationship,” Dr. Doug Bird said. “The more that Martu hunt, the more they burn. The more they burn, the patchier the landscape is. And dingoes and monitor lizards and some other critters, native critters, really like that patchwork.”
But it isn’t as if the Martu returned home, and everything went back to normal. The Martu now consume more western food, some only hunt on weekends and invasive species and extinctions still happen. But the patchwork is coming back.
Mr. Taylor, who lives in Perth, says he finds solace hunting in the country, paying respect to the animals and sharing the food with family. “I’ll just be here, now, today, and know that the country is healthy because people are burning and looking after it how people have done for millenia.”
The Martu story isn’t small or isolated. It’s applicable to about a quarter of Australia, where other Aboriginal Australians practice long-held traditions on their lands. It also extends to groups around the world, like American Indians, whose generations of knowledge are starting to be tapped to benefit biodiversity and government agencies trying to manage it.