The western black rhinoceros, the dodo bird, and the woolly mammoth are all species that have gone extinct because of humans.

As climate change continues to ravage cities around the world — resulting in increased instances of extreme heat, flooding, and forest fires — more people are understanding the extent to which human activities impact the environment. But for millions of plant and animal species that have disappeared from the planet, humans have long had a hand in changing the natural world, for better or worse.

Extinctions are naturally occurring events that drive evolution and allow the earth to adapt to change. Five mass extinction events have occurred throughout our planet’s history, and scientists now believe we are entering our sixth. What makes this time different, however, is the fact that extinctions are occurring hundreds of times faster than usual because of human activity.

“Since the 1970s, we have become aware and taken steps, albeit incomplete ones, to address pollution and toxic chemicals,” Greg Costello, conservation director for the Wildlands Network, told Global Citizen. “We have been much slower to recognize the damage to ecosystems and the current free fall in biodiversity. It is unwise, indeed in my view foolishly arrogant, to believe that our very existence is not directly correlated with the health of the natural world.”

Like other species, humans are an important part of ecosystems. We help regulate natural processes by feeding on various plants and animals and cultivating land for agriculture. But when our activities threaten the genetic diversity of wildlife, zap natural resources, and contribute to the destruction of the environment, the whole system suffers. 

Thankfully, scientists have implemented a number of solutions to protect wildlife and restore ecological communities. One of these is called rewilding.

What Is Rewilding?

Rewilding is a conservation strategy used to promote biodiversity in ecosystems by reintroducing plant and animal species that have been driven out, largely due to humans. Bringing these species back into a certain environment can help struggling ecosystems self-regulate and return to their natural processes.

For many conservationists, or those who work to protect and preserve the natural environment, rewilding is as much an activity of the heart as of the land.

In order to adequately defend the planet and its diverse life forms, humans have to accept that they are part of a larger system instead of attempting to rule over everything. Conservation organizations attempt to promote a holistic return to nature through initiatives like rewilding, which can mean anything from reintroducing apex predators to restoring land that has been exploited.

“While natural systems evolve slowly, as anyone who has ignored a piece of property for a while can attest, nature is pretty adept at reclaiming what we let alone,” Costello said. “But our rapid and consumptive changes to natural systems is occurring at a speed many times greater than natural processes, and the impacts of climate change are occurring at a pace that far exceeds anything that has previously occurred in world history.”

For this reason, many conservationists believe rewilding is less an act of human interference in nature than a way for humans to restore what they have changed. And though there are many different routes conservationists may take to rewild the environment, the overarching goal is the same: Let natural processes take control so that ecosystems can become self-sustaining.

3 Key Facts About Biodiversity on Earth

How Can Rewilding Help Restore Our Planet’s Biodiversity?

Modern humans evolved on Earth and began interacting with other species about 200,000 years ago, but we have only recently distanced ourselves from the natural world. This distance is part of the reason why our activities have ramped up, causing harm to the environment around us.

“It is only since the Industrial Revolution and the rapid development of modern agriculture that we have been able to be less reliant on, and hence live somewhat apart from, the natural world in which we evolved,” Costello said. “In that process we have wiped out millions of other species, destroyed much of the earth’s productive soils, polluted our waterways, and introduced long lasting toxins into our lands, waters, and bodies.”

But rewilding can help reverse some of these unintended consequences. One method concerns ecological restoration, or helping areas that have been damaged recover. By reintroducing native plant species that have been lost, planting trees, and stopping human activities that degrade an area — through exploiting resources or polluting waterways — ecosystems can better regulate the environment. For this reason, rewilding is a nature-based solution for fighting climate change.

Forests and land ecosystems are known as a “carbon sink,” absorbing a net 7.6 billion metric tons of carbon dioxide per year. Rewilding some areas of the world by planting more forests can decrease the amount of carbon emissions humans put into the atmosphere. However, scientists point out that global warming has impacted land ecosystems’ ability to absorb carbon, which is why planting trees alone cannot stop climate change.

Another method of rewilding concerns connecting wildlife communities to increase levels of biodiversity, which in turn affects the food chain to help regulate ecosystems. Costello told Global Citizen that constructing wildlife crossings along highways can reconnect habitats that humans have divided, as well as help animals that migrate.

“Road and human development are major barriers to movement, and absent reconnection, it may be a bleak future for many of our fellow residents,” he said.

Perhaps the most well known example of rewilding is the introduction of apex predators into an ecosystem. Because the environment has changed due to human activity — such as through overhunting animals like the western black rhinoceros to extinction — some ecosystems have become unstable. Species that are not regulated by predators can prevent vegetation growth or spread disease to humans.

“For instance, we eliminated large predators throughout the eastern United States, and now we have an explosion of deer populations that destroy eastern forests, invade farmer’s crops, eat the flowers out of urban dwellers yards, are a hazard to drivers on our roadways big and small, and provide a ready vehicle for the explosion of ticks, and resultant Lyme disease that poses a human health risk,” Costello said.

He added: “Reintroducing cougars, including helping the Florida panther expand its range, and supporting the recovery of the red wolf population in North Carolina would be a start to reducing the deer population, and a start to returning to the more natural state that existed in the past.”

What Are Some Examples of Rewilding?

One of the most successful rewilding efforts occurred in Yellowstone National Park in the United States through the reintroduction of wolves into the park’s ecosystem.

The last wolf in Yellowstone was killed off due to overhunting in the 20th century, which altered how the food chain regulated itself and threatened the biodiversity of the environment. Elk populations increased for decades without wolves to hunt them, leading to a reduction in vegetation as they overgrazed on plants.

Not only did this reduce the beaver population, which rely on trees for food, but it also impacted the natural landscape of the park. Less vegetation leads to land erosion, and the absence of beavers building dams and ponds affects the water flow of rivers and streams. As elks continued to overgraze, scientists worried about environmental degradation.

In 1995, biologists introduced eight Canadian wolves into Yellowstone and kept track of how the wolves interacted within their new ecosystem. As the wolves hunted, the elk population decreased, which allowed trees and plants to flourish in the park. Beaver colonies quickly expanded, providing habitats for other species like coldwater fish and birds. With a clear top-down regulation system, where wolves are at the top of the food chain, plant and animal species could coexist and regulate the ecosystem together.

Another example of rewilding is currently taking place in oceans around the world.

Kelp forests are important for marine ecosystems, providing a habitat for thousands of organisms and absorbing carbon dioxide. They typically grow in shallow, open waters because they need light to prosper. But for years, rising sea temperatures and human activity in oceans have destroyed kelp forests.

The Sussex Kelp Restoration Project is one of many kelp forest conservation projects taking place to promote biodiversity in oceans and fight climate change. To restore kelp forests, the project has campaigned to limit trawling, a method of fishing that involves pulling a net through the water and can dislodge kelp from ocean floors. Other rewilding efforts are empowering volunteers to plant, grow, and monitor kelp to build up kelp forests that have been lost.

What Are the Risks of Rewilding?

Even rewilding initiatives are not without their controversies. As conservationists debate whether to reintroduce keystone species, or organisms that are important for regulating ecosystems, into an environment and how to promote biodiversity among plant species, they have to keep in mind several factors.

“The major disadvantage to rewilding efforts is that ecosystems are so complex that it is hard, if not impossible, to fully predict the unintended impact of rewilding efforts,” Costello said. “Human efforts to ‘fix’ things always come with some risk; indeed, history is full of examples where we have tried to fix environmental conditions and made things worse.”

While introducing an apex predator can help regulate the overpopulation of other species, conservationists have to make sure that they do not eradicate an entire population of animals within a given ecosystem. Even efforts to plant more trees with the hope that they will capture carbon dioxide from the air can have unintended effects on the environment, particularly with nonnative species.

And though some rewilding efforts may want to return an ecosystem to its pre-human state, nature is sometimes better off adapting and regulating itself.

“We must not forget that ecosystems continue to evolve, and trying to rewild a system to what it was hundreds of years ago, and then maintain that status quo, is likely neither possible nor appropriate,” Costello said. “Ecosystems are always evolving, and we must recognize and accept this in our efforts.”

He added: “But I don’t believe those potential disadvantages are reasons not to engage in common sense measures.”

Rewilding organizations are attempting to implement these common sense measures around the world. From demanding that world leaders protect existing habitats from human exploitation to reconnecting landscapes to help with animal migration, rewilding is a valuable tool to defend the planet and all of its inhabitants.

“If we are smart and exercise precaution, we can reconnect, restore, and rewild landscapes,” Costello said. “In doing so, we can help rebuild the resilience of ecosystems and build our own resilience as a biological species.”

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Global Citizen Explains

Defend the Planet

What Is 'Rewilding' and How Can It Help Restore Our Planet's Biodiversity?

By Jaxx Artz