This city had a flooding problem. So it turned to an animal that had been extinct there for 400 years

By Laura Paddison, CNN

Ealing, West London (CNN) — A few hundred feet from a McDonald’s and a strip mall, sandwiched between busy and polluted roads, a lush urban wetland is being built by an unusual and furry group of city residents: beavers.

This corner of Ealing, a borough in West London, used to flood regularly during heavy rainstorms, with water sweeping into local streets and inundating the nearby Greenford tube station, part of the London Underground.

To alleviate the problem, local authorities had considered a traditional engineering project, carving out an artificial reservoir using heavy machines and concrete. But then, a group of local conservationists had a different idea.

“Why don’t we try a nature-based solution?” said Sean McCormack, a veterinarian, wildlife conservationist and project leader at the Ealing Beaver Project. “Why don’t we bring back beavers?”

In 2023, the project moved a family of five wild beavers onto a 24-acre stretch of land in Ealing called Paradise Fields. “It was kind of a forgotten and neglected space,” McCormack said. Over the last few years, it’s been transformed.

As climate change supercharges storms and other extreme weather, rewilding projects are emerging as one solution — harnessing the skills of animals to create more resilient landscapes. But, experts warn, the efforts must be done carefully.

Beaver engineers

Wild beavers went extinct in the UK around 400 years ago, as humans hunted them for their fur, meat and scent gland secretions, which have a musky, vanilla-like fragrance and were used as food flavoring and in perfumes.

In recent years, however, beaver reintroductions have started to become more popular in the country because these semi-aquatic rodents are amazing natural engineers.

Their strong teeth — fortified with iron that makes them a striking orange color — can chisel through sticks and trees. They eat the bark and use the wood to build dams, creating natural reservoirs.

These pools offer the beavers refuge from predators; for humans, they provide natural flood control. Beaver engineering can turn the landscape into a sponge, allowing it to hold more water when it rains, meaning less runs off to flood downstream.

Beavers dig canals, too. These are “like little micro-streams that radiate outward from their ponds across valley bottoms like a spiderweb of water,” said Emily Fairfax, an assistant professor of geography at the University of Minnesota, who is not involved in the West London project. “These further mitigate flood damage by spreading the floodwaters out over a larger area.”

The flat-tailed rodents can also provide protection against other extreme weather. The wetlands they create are helpful during droughts, as water can percolate into surrounding dry areas. They can also guard against wildfires because the land is essentially too wet to burn, Fairfax told CNN.

There’s a joke in the beaver science community “that if you’ve got a problem, there’s a beaver for that,” Fairfax said. It’s an oversimplification, she acknowledged, but beavers “really do provide a staggering number of ecosystem services.”

‘Beaver bombing’

So far, the London initiative has been a success. By the beavers’ second winter at the site, there was no flooding in the target area for the first time in a decade, McCormack said.

The beavers’ work has also created a mosaic of different habitats, encouraging other animals to flock to the site, including birds, butterflies, bats and even freshwater shrimp and fish.

There are currently eight beavers at Paradise Fields, as well as a new litter of babies, called kits, that were born in the spring. The project won’t know how many kits there are until they emerge from their lodge, which is likely to happen later this month, McCormack said.

Beaver rewilding projects are taking off across the US, too, especially in the West.

But beavers cannot be released just anywhere, Fairfax said. There needs to be enough food, water and space for them to build their wetland home. Humans near the site must be receptive to the animals, and a community needs a contingency plan in case the beavers engineer too close to human infrastructure.

Not everyone embraces beaver rewilding, especially when — unlike the Ealing project — the animals are introduced illicitly, said George Holmes, a conservation professor at the University of Leeds. It’s a tactic sometimes called “beaver bombing.”

Beavers can create problems for farmers and landowners. The tunnels they dig in riverbanks can be big enough to trap cattle and machinery, and there are concerns about flooding of farmland and infrastructure, said Holmes, who co-authored a recent study on local opposition to beaver rewilding.

“Beavers are seen as just another thing that farmers (and others) didn’t ask for, which is imposed on them,” he told CNN. He acknowledged beaver rewilding can bring positive impacts but urged caution. “There are a lot of people out there promising that beavers will do all these marvelous things, but I think they are making promises they can’t keep.”

Fairfax said she understands the oppositon. “It does sound absurd to trust a 70-pound pond rat to make engineering decisions and control the waterways we depend on,” Fairfax said.

But beavers have been engineering ecosystems for millions of years, she added. In the right areas, “we should trust them to build wetlands — that’s their specialty.”

The Ealing community has been receptive. The day CNN visited, a dozen people approached McCormack asking about beaver sightings; a group of men sat on a bench enjoying post-work beers and beaver spotting; children walked home from school past beaver dams; and a gaggle of wildlife enthusiasts were led on a “beaver safari.”

A dense city might not seem like an intuitive place for beaver rewilding, but bringing nature back to urban areas is hugely beneficial, McCormack said. “We’re demonstrating here that actually it’s not that wild an idea to live alongside beavers.”

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