In a river valley in Devon, beavers are doing something remarkable. They are building dams, creating ponds, felling small trees and, in doing so, transforming the hydrology of an entire catchment. Where once there were straight, fast-draining ditches, there are now meandering waterways, boggy margins and diverse aquatic habitats. Flood risk downstream has decreased. Water quality has improved. Species that had been absent for decades — water voles, otters, dragonflies — are returning without anyone planting them or programming them. The beavers have simply restored the conditions they need.
The Devon Beaver Project is one of the most closely studied rewilding experiments in Britain, and its findings have been striking. A five-year study published in 2020 showed that the beaver-managed catchment retained significantly more water during dry periods, released it more slowly during floods, and supported a dramatically higher density of wildlife than comparable waterways. The beavers, absent from British rivers for around four hundred years, had rebuilt what centuries of "land improvement" had destroyed — in five years, at no cost to anyone.
What Is Rewilding?
Rewilding is one of the most contested and exciting concepts in contemporary conservation. At its simplest, it means restoring ecological processes to degraded landscapes — allowing natural dynamics to reassert themselves rather than managing land towards a predetermined outcome. In practice, this can range from removing fences and letting scrub and woodland regenerate naturally, to reintroducing species that once played key ecological roles: keystone species whose presence reshapes ecosystems in cascading ways.
"Rewilding is not about going backwards. It's about giving nature the space and the tools to do what it does better than we can."
The Species Coming Back
Britain is one of the most ecologically impoverished countries in the developed world. We have lost a higher proportion of our biodiversity over the past century than almost any comparable nation. The list of species once native to Britain and now absent includes the grey wolf, the lynx, the brown bear, the white-tailed eagle (now successfully reintroduced), the red kite (also reintroduced), the beaver (now present in several rivers following official reintroduction), wild boar (self-reintroduced in several areas) and the marsh harrier.
Each of these species played specific ecological roles. Wolves and lynx regulated deer populations, preventing overgrazing of woodland. Beavers created wetland habitat. Bears and boars disturbed soil and created habitat diversity. Their absence has had cascading effects on every level of the ecosystems they once inhabited.
The Arguments Against
Rewilding has passionate opponents as well as advocates, and their concerns deserve serious engagement. Farmers worry about predation of livestock and competition for land. Communities near proposed reintroduction sites worry about safety and economic impact. Conservationists who have spent decades managing particular habitats for specific species worry that rewilding's more hands-off approach will undermine work that has produced real results.
The lynx question is perhaps the most contentious. Lynx are shy, elusive predators that pose essentially no threat to humans, but they do kill deer and occasionally sheep. In Scotland, where deer populations have caused severe overgrazing of upland habitats, the ecological case for lynx reintroduction is strong. But the political and cultural case requires the buy-in of farming communities who have legitimate economic concerns.
The Knepp Experiment
The most celebrated rewilding project in Britain is the Knepp Estate in West Sussex, where Isabella Tree and Charlie Burrell have spent twenty years restoring a failing conventional farm to a mosaic of scrub, grassland and woodland managed by herds of free-roaming cattle, pigs, deer and ponies. The results have been extraordinary. Turtle doves, peregrine falcons, nightingales and purple emperor butterflies — all declining or absent across Britain — are thriving at Knepp. The estate has become a model for what British land can look like when it is managed for ecological processes rather than agricultural yield.
Knepp is also economically viable. Its income now comes primarily from nature tourism, meat production from its free-roaming herds, and educational activities. It demonstrates something important: that rewilding is not in fundamental conflict with economic productivity, provided we are willing to reimagine what productivity means.