Rewilding: What is it & How Does it Work?

Written by Connor Yanz

Optimism may feel difficult for today’s environmentalist.  Amidst the constant news of a warming climate and loss of biodiversity, anyone concerned about our environment can feel like they’re fighting a losing battle.  Everywhere we look, hope seems lost. Let’s look to rewilding.

What is Rewilding? 

Rewilding means how it sounds – returning an area to its natural, wild state.  Not just conservation, but active restoration of lost lands: forests chopped and burned for agriculture; wetlands drained and prairie bulldozed for new development.  Rewilding is an answer: giving nature the tools – reintroduction of native plant & animal life – and the space – land for habitat. Then, getting out of the way.

Cores, Corridors & Carnivores

Carnivores play an important role in the process of rewilding.  Aldo Leopold knew as much back in the 1940’s.  Originally employed by ranchers to help kill troublesome wolves in New Mexico, he eventually recanted his mankind-take-all mindset, noting the importance of wolves in maintaining the balance of their ecosystem.

Leopold authored The Sand County Almanac – the encyclopedia of rewilding, before it had a name – describing what he believed as a responsible relationship between people and land.  He later was elected to Theodore Roosevelt’s conservation organization The Boone and Crockett Club, worked on management plans for the Grand Canyon, and influenced the preservation of wilderness areas in New Mexico and elsewhere.

Decades later, we’re rediscovering the importance of the wolves and their top-down effect on the environment.  This was captured elegantly by George Monbiot.

And this doesn’t just apply to wolves. “Trophic cascades” are applicable to other megafauna like bears and lions, as well as unassuming participants like beavers*.

But carnivores need a lot of space.  Especially space with low human density.  They need cores, unobstructed habitat areas to roam freely.  These cores should have little human input, so that the natural regenerative processes of the flora and fauna can take place.

These cores should be connected via corridors, to ensure free travel to and from cores, and ensure the long-term genetic diversity of any species that live there.

Single Large or Several Small?

This leads to a debate often referred to as SLOSS, which stands for Single Large or Several Small. Should we focus time and resources on preserving a smaller number of large ecosystems? Or a large number of smaller ones? Conservation projects have historically taken the ‘single large’ approach.

The US. National Parks are a prime example. While ambitious and prudent for their time, the creation of our national parks resulted in large and secluded ecosystems. They don’t necessarily abide by natural boundaries like mountain ranges, watersheds, or animal migration patterns. Nor is there enough focus on the interconnectedness of surrounding areas, which are often dense and overdeveloped.

This leaves our parks cut off and isolated, the results of which are lethal: most national parks have lost species since establishment, according to the landmark study in 1987**.

Many have consequently compared our parks to islands, where the species present are subject to the equilibrium theory of island biogeography. This theory suggests that species on an island will face extinctions from, and immigrations to, their location, and eventually converge toward an equilibrium. The more isolated an ecosystem, the less migrations to it and the lower its equilibrium number.

The studies & conversations around this hypothesis have ignited a push toward the ‘several small’ side in the SLOSS debate. It suggests that our country’s most beloved public places, as well as other isolated ecosystems, could continue to see a decay in biodiversity unless we increase their connectivity.

Paying Dividends

This is where rewilding initiatives fill the void. Efforts to connect ecosystems yield endless benefits. Large keystone predators can travel more freely, causing a top-down chain reaction influencing the landscape. Previously unconnected natural areas become healthier and more resilient to species extinction. This keeps waterways cleaner, prevents soil erosion, and increases tree growth.  Ultimately these results help sequester more carbon and even help fight the effects of climate change.

The Paris Agreement’s goal to keep average global temperature rise below 2°C by 2030 has sparked much discussion about the best approach to get there.  One thing is clear – cutting emissions simply isn’t enough.  Therein lies an opportunity for rewilding enthusiasts – it’s one of the most efficient and inexpensive ways to combat climate change.

“Natural” climate solutions, including restoration of forests, wetlands, & grasslands often require very little human intervention. Leave them be, and let nature do the work.  This skips the ‘middleman’ – investing large sums of money into carbon capture technologies – and allows natural & efficient processes to take hold.  These techniques could potentially handle up to 37% of the CO2 capture needed by 2030 according to one study.

Where We Come In

The Yukon to Yellowstone Initiative was one of the first organizations to address rewilding. Activists in 1993, keenly aware of the benefit of keeping the diverse forests, grasslands, parks & river networks in the region connected, began organizing to preserve this landscape.

They oppose major development threats which could sever the corridor; making land use plans, advocating for wildlife crossings over roadways, and mapping bear & other fauna movements.

Another example is Wildlands Network, which identified three ranges as a major focus of reconnecting ecosystems. The Eastern (following the Appalachian Trail), Western (following the Rocky Mountains between Canada/US/Mexico), & the Pacific Wildways (the west coast of Canada/US/Mexico) have ambitious and science-backed goals for connecting migration corridors to maintain and increase biodiversity.

These groups are accomplishing both boots on the ground activism and top down rewilding promotion on state and federal levels. Hopefully with the increased exposure – March 20th, 2021 was the first ever World Rewilding Day – these organizations can see more monetary support and volunteers chipping in.

Locally we can pitch in, too.  Rewild Mission Bay is aiming to restore the wetlands in northeast Mission Bay and allow for native plants and animals to flourish. Other areas nearby could use our involvement. Sections of private land in Otay Mountain Wilderness and Pine Creek Wilderness areas were purchased by the Wilderness Land Trust and then transferred to the Federal government, for permanent wilderness designation.

They are one of the few organizations in the US whose sole focus is to attain private land – often land with potential for detrimental industrial or commercial development – in or near wilderness areas, so as to strengthen and increase the connections between wildlife safe havens.  Both Hauser & Jacumba Wilderness, as well other areas of southern Anza Borrego, are currently identified as ‘threatened wilderness’ according to the WLT. 

If we can preserve our current patchwork of wilderness areas, while strategically increasing their connections via rewilded lands, we can stabilize our ecosystems and reverse the trend of environmental degradation. 

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*The felled, chewed up trees make habitat for bats.  Dammed up river sections lead to slower moving water – meaning less river erosion. Slower water, and waterlogged ground on the peripheria means more bugs stopping and laying eggs. More bugs results in fatter and healthier fish, ducks, & waterfowl.

**A land-bridge island perspective on mammalian extinctions in western North American parks –  William Newmark, Ph.D