Rewilding is a high-tech solution to saving endangered species


Antony Funnell , ABC Radio National

Date Published
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Elizabeth Ann is tiny and playful – and she may hold the key to the survival of her entire species.

Born in December 2020, the tiny carnivore is an endangered black-footed ferret, successfully cloned from a frozen DNA sample collected in the early 1980s.

And for the black-footed ferret population in North America, she represents the difference between future health and possible extinction.

Her birth also marks the latest chapter in a once-controversial conservation approach known as rewilding, which seeks to reverse ecological damage by reintroducing lost animals to their original habitats.

It’s controversial because its original focus was on the reintroduction of apex predators like wolves and bears across Europe, an initiative that some local communities objected to.

But proponents say rewilding has matured and now represents the best hope for restoring depleted landscapes and rebalancing natural ecosystems. Now researchers are using the latest technology to do just that.

‘Genetic Rescue’
Researchers at the US-based conservation organisation Revive & Restore use DNA sequencing and advanced gene-editing tools as part of their work. It is an approach director of conservation innovation, Michele Weber, calls “genetic rescue”.

The organisation’s primary focus is on expanding the gene pool of endangered species, thereby decreasing the risks associated with inbreeding. Elizabeth Ann is a prime example.

“Thousands of black-footed ferrets have been bred by the captive breeding program over the last several decades,” says Dr Weber, “but all of the ferrets that are alive today are either siblings or cousins and they carry very closely related DNA.”

Elizabeth Ann’s DNA is important because it’s not carried by any other living ferret. The ancestor from which she was cloned died almost four decades ago.

And so, by introducing a new member to the colony, Elizabeth Ann will provide a new genetic variation which, over time, should help strengthen the resilience of the whole species.

But while the Revive & Restore approach is highly interventionist, Dr Weber says genetic rescue is done in support of natural processes – not in spite of them.

“It’s about making this genetic diversity available for natural selection to act on, so that evolutionary processes don’t stall and these populations do not suffer inbreeding effects.”

Resetting Ecosystems
Rewilding also has the potential to help to reset damaged ecosystems, according to Deakin University ecologist, Euan Ritchie, particularly where invasive species have taken hold.

“We can’t go back in time and right the wrongs that we’ve done,” he says.

“But we can think about what future we might have. So, how might our environments look if we could bring back some of these species?”

In the Australian context that means reassessing our attitude toward the dingo and, as Dr Ritchie suggests, strategically reintroducing them into many rural areas they were once expelled from.

“The dingo has a really important role in the landscape in regulating things like kangaroo numbers, getting rid of some feral animals and keeping things in balance,” he says.

“When they die, if [kangaroos and feral animals] are not being eaten and are not removed from the landscape, that can be a source of disease.”

Dr Ritchie also argues there could be a case for reintroducing the Tasmanian devil to the Australian mainland, even though it’s been missing from that environment for around 3,000 years.

“Ecologically speaking, it’s not actually a long time. And we could think about whether the Tasmanian devil might help us to control things like feral cats. There is some evidence that they deter the behaviour of cats.

“So, bringing back some of these predators is a really positive thing that we might be able to do for conservation.”

The Need to Consult Communities
Dr Nathalie Pettorelli, a senior research fellow with the Zoological Society of London, says caution is needed when rewilding in order to avoid “unpredictable trajectories”.

“You can get into a situation where disease might increase or certain risks to human populations might increase,” she argues.

She points to tensions that arose between farmers and conservationists after the re-introduction of wolves and bears in several European countries a few years ago.

“If communities are not engaged with decisions about whether or not to go for rewilding and how it should be done, then you can get a lot of conflict,” Dr Pettorelli says.

“It will not work if people are not onboard. And because of this, it’s really important to think about the social aspect and the social impact of rewilding.”

She says there’s often vagueness around specific targets and a general lack of guidelines for implementation.

Efforts have been underway in Europe to address those deficiencies, she says, but many local authorities remain unconvinced by the approach.

“When you invest in a form of conservation action, you need to know whether it will work and what it will deliver,” Dr Pettorelli says.  

“Rewilding is based on the concept of improving the functioning of ecosystems but the scientific community as a rule is not very good at really measuring ecosystem function,” she says.

“So, currently we are lacking an example and a standard method to demonstrate that rewilding is working.”

Dr Ritchie agrees proper assessment and monitoring procedures are crucial.

“There is a challenge when you talk about bringing particularly large predators back to the landscape, which may kill and eat livestock.

“But we can’t generalise about how the farming community will react to the reintroduction of predators. Some farmers like having dingoes on their property because they control kangaroo numbers and things like feral pigs and goats.”

He says the important thing is to start small and to monitor how the reintroduced animals behave and interact with other species.

How Extinct is Too Extinct?
How far back in time can you go before a species is no longer relevant to its original environment?  

For Revive & Restore, the answer is a very long way back indeed – right back to the Ice Age.

For more than a decade now, the organisation has been trying to create a new breed of Asian elephant that would closely resemble the woolly mammoth. The project is being run in conjunction with researchers at Harvard University.

But while their mission has regularly grabbed headlines because of its sheer novelty factor, Dr Weber says “de-extinction” efforts must centre on current real world needs.

“We’re thinking about how to edit Asian elephant genomes and introduce some of the mutations from the woolly mammoth genome that we know were important in conferring cold temperature tolerance,” she says.

“The genomes are quite similar and if we can make a few of these important edits, things like increasing the fat, making the hair furrier, and adjusting the blood oxygen chemistry, then we think that we could build an Asian elephant that would tolerate the cold temperatures in Siberia quite well.”

For Euan Ritchie, it all depends on the level of environmental change that a targeted area has experienced over time.

“I don’t think there’s an easy cut-off point. It’s a fascinating question to ponder, and that’s been discussed even in the context of the thylacine,” he says.

While the thylacine – or Tasmanian tiger – only became extinct in 1936, Dr Ritchie says doubt exists as to whether it would now fit into the modern island landscape even if it could be genetically resurrected, because much of its habitat has largely been removed.

And, he says, while rewilding can help build species’ resilience in the face of climate change, the rate at which the world is warming could render the approach useless.

“If we don’t manage to avert the worst possible scenarios, which are temperature increases above 1.5 to 2 degrees, it may be that quite large areas become unsuitable for a whole range of species, including species that we might be trying to bring back through rewilding,” Dr Ritchie says.

But he’s adamant about the importance of taking risks.

He says the rate of species loss and ecosystem degradation is so great, that doing nothing is not an option.

“Whether it be invasive species or climate change, we do need new approaches to hopefully increase the resilience of systems, and rewilding is one option that we have,” he says.

“And so, we should be taking these calculated risks, but do[ing] it in a careful way.”