The 3,500-acre Knepp Estate, in West Sussex, southern England, was once “depleted, polluted, dysfunctional farmland,” says the estate’s co-owner, Isabella Tree. Now, she says it is one of Britain’s most significant biodiversity hotspots.
By Jasmin Sykes
A walk through the Knepp Estate, in southern England, could lead you past beaver wetlands, breeding herons and free-roaming Exmoor ponies — all accompanied by the distinctive cooing of a turtle dove.
“It’s a sound that used to be part of our culture. Every person’s summer in England would have been characterized by that sound,” says Isabella Tree, who owns the 3,500-acre estate in West Sussex with her husband Charlie Burrell.
Turtle doves were once abundant in the UK, but since 1994, numbers have declined by 98%, and the bird has been on the UK Red List – meaning it is considered a threatened species – for 20 years.
At Knepp, however, the bird seems to be bouncing back. A recently published, two-decade review of wildlife on the estate found that the number of singing males rose from just two in 2008, to 22 in 2024.
The increase is part of a broader surge in biodiversity at Knepp since Tree and Burrell began a rewilding project in 2001 on the former farm.
“We never thought that in 20 years we could have gone from being this depleted, polluted, dysfunctional post-industrial farmland, to being one of the most significant biodiversity hotspots in Britain,” says Tree.
Successes include an 870% rise in the number of dragonflies and damselflies on the estate between 2005 and 2025, and 110% growth in butterfly species richness — including the elusive purple emperor butterfly, which Knepp now houses one the UK’s largest populations of — with 283 individuals counted in a single day in 2025.
Breeding bird numbers have increased ninefold since 2007, with nightingales — another bird once common across the UK but now under threat — making a comeback: Sixty-two singing males were spotted last year, up from just nine in 1999.
From intensive farming to rewilding
The estate, which includes a 19th-century castle, has belonged to the Burrell family for over 200 years. Charlie Burrell inherited it in 1985 and, after attending agricultural college, he planned to continue farming in the same intensive manner his grandparents had since World War II.
But by the late 1990s, with the farm producing low yields and costs rising, the estate was £1.5 million ($2 million) in debt. Tree says, “it was finally realizing that no amount of intensification was going to make farming work on this land” that inspired them to set about rewilding.
They began by sowing native wildflowers, grasses and seeds in the 350-acre parkland area around the estate house. They then introduced Tamworth pigs, Exmoor ponies, longhorn cattle, and red, roe and fallow deer to the wider estate.
Internal gates were removed to allow the animals to roam freely, spreading seeds and nutrients through their dung and fur.
Beavers, which became extinct in the wild in the UK in the 16th century, were also introduced to Knepp, building dams in waterways to create ponds, which Tree says have attracted breeding birds.
But after these re-introductions, Tree says “the whole idea of rewilding is about letting go and letting nature evolve.”
Allowing Knepp’s once orderly arable fields to grow wild with thorny scrub has provided a habitat which is “rocket fuel” for turtle doves and nightingales, says Tree.
“It provides fantastic thorny protection for nests, but it also provides all the food resources that many songbirds need, including seeds and buds and nuts and berries,” she explains.
Challenges for rewilding
But despite flourishing at Knepp, Tree thinks turtle doves have a “slim chance” of survival in the UK given broader habitat loss.
“If we (the UK) were really serious about reversing the trends of biodiversity loss, we would be rolling out rewilding on every spare inch of land that we possibly can,” she says.
Almost 70% of UK land is farmed, which Rob Stoneman, director of landscape recovery at the Wildlife Trusts, a group of UK wildlife charities, says is one of the primary drivers of species decline in the country.
“We’ve gradually pushed wildlife out,” he says. “That’s bad news for everybody. It’s bad news for flooding. It’s bad news for drought. It’s bad news for the climate.”
While the government has pledged to restore or create more than 500,000 hectares (1.24 million acres) of wildlife-rich habitat by 2042 in England, Stoneman says rewilding initiatives still face obstacles.
“All of our education through agricultural colleges, the way that we deliver land subsidies, the advice that we give farmers … all of those systems encourage farmers to be intensive,” he says.
Stoneman adds that regulatory barriers are an additional challenge. The Dangerous Wild Animals Act 1976 outlaws the keeping of bison and wild boar without a licence that is difficult to obtain — two species Tree would like to see released onto the Knepp Estate.
“Large, free-roaming herbivores are the drivers of ecosystems,” says Tree.
An “economic success story”
Stoneman hopes that Knepp’s success will pave the way for more rewilding programs across the country, particularly in upland areas — typically 600 to 700 meters above sea level (1,969 to 2,297 feet) — where damaged peatland emits large quantities of carbon and low-fertility soil makes for unproductive farming.
“Knepp is a light showing the way,” he says, adding that alongside its biodiversity improvements, the estate is “an economic success story.”
Where Knepp had just 23 full-time staff when the land was farmed, it now has 168 employees, and 200 people work in old farm buildings on the estate that are leased to other companies.
Knepp now has a glamping business, offering accommodation in cozy shepherd’s huts, yurts and treehouses, and offers safaris, guided walking tours and rewilding workshops.
The large, free-roaming animals — which are managed to prevent overgrazing — provide a consistent supply of organic meat, sold in the estate’s shop and seasonal restaurant, which has recently been awarded a Michelin Green Star for its sustainable and eco-friendly gastronomy.
However, rewilding has faced criticism from some farmers who fear it could jeopardize their livelihoods and domestic food production.
The UK’s National Farmers’ Union has previously argued that British farms provide vital wildflowers and hedgerow habitats, and that the government “must focus on land sharing to deliver food security and environmental delivery, not a singular approach that risks undermining the social fabric of rural communities.”
Both Tree and Stoneman insist that rewilding to improve biodiversity isn’t a threat to farmers, but rather an essential support to food systems, which are increasingly vulnerable to the effects of climate change.
“Farming depends on having nature as a buffer to produce everything from the dung beetles, the pollinating insects, the natural pest control, the buffers for extreme weather events … all these things that food production relies on,” says Tree.
The estate is now working with farmers and local communities in Sussex as part of the Weald to Waves project, to create a 100-mile “wildlife corridor,” from the Ashdown Forest in the east of the county to its south coast.
Tree is confident that the biodiversity successes of Knepp, can be repeated elsewhere. “If it can happen here, it can happen anywhere,” she says. “It has been an extraordinary story of hope.”
Source: https://edition.cnn.com/world/rewilding-success-knepp-estate-c2e-spc
