In 2001 Charlie Burrell and Isabella Tree, the owners of Knepp Estate in the south of England, decided to transform their farm by "rewilding" it. They introduced large mammals including Tamworth pigs, which act as "ecosystem engineers" to help restore biodiversity. When the pigs rootle in the mud with their snouts, it helps create habitats for other animals.
Charlie Burrell/Knepp Wildland
Cows -- like these English longhorn cattle -- can carry over 200 different types of seeds on their fur and in their hooves and dung. This helps distribute nutrients and plants across the estate, creating a "kaleidoscopic landscape," says Burrell.
Charlie Burrell/Knepp Wildland
Part of the rewilding process at Knepp involved collapsing a canalized waterway to create a more natural wetland setting, and removing fencing to allow animals to roam free.
Charlie Burrell/Knepp Wildland
Burrell inherited Knepp estate in 1985, aged 21. It was then a conventional dairy and arable farm growing crops like maize, winter wheat, barley and oats.
Charlie Burrell/Knepp Wildland
After 17 years of conventional farming, Burrell and his wife, Isabella Tree, decided to take a gamble on rewilding for the sake of their family.
Charlie Burrell/Knepp Wildland
The 3,500-acre estate -- which includes a 19th century castle -- has been in the Burrell family for over 200 years.
Charle Burrell/Knepp Wildland
Nearly two decades after rewilding began at Knepp, the landscape has been transformed from orderly fields into a patchwork of tangled thickets, rugged pastures and meandering waterways which provide a rich habitat for birds and grazing for large herbivores.
Charlie Burrell/Knepp Wildland
There are three types of deer on the estate - fallow, roe and red deer. This bellowing stag is a red deer.
Charlie Burrell/Knepp Wildland
The Exmoor pony is a distant relative of the tarpan -- a wild horse that was common in Europe in prehistoric times. This one is grazing in a wildflower meadow, replicating the impact that its ancestor -- which is now extinct -- would have had on the land.
Charlie Burrell/Knepp Wildland
The large mammals on the estate need to be culled to keep numbers at levels that the land can sustain. This provides a source of free-range meat, for mostly London-based customers, and generates income for the estate.
Charlie Burrell/Knepp Wildland
The mosaic of habitats created by the large animals has resulted in an explosion of life, including many insect species. Pollinators have made a beeline for Knepp's wildflowers and are an important source of food for the estate's birds.
Charlie Burrell/Knepp Wildland
The elusive purple emperor butterfly has flourished in the acres of sallow trees on the estate.
Charlie Burrell/Knepp Wildland
Knepp has attracted many rare bird species. This summer, white stork chicks hatched at Knepp, the first time this bird has been born in the UK for hundreds of years.
Charlie Burrell/Knepp Wildland
Turtle dove populations in the UK have declined by up to 98% in recent decades but the birds have found a refuge in Knepp's leafy canopies, where numbers are rising.
Charlie Burrell/Knepp Wildland
The large numbers of birds on the estate create a cacophony of sound during the spring and summer months. This great tit has a distinctive, two-syllable song.
Charlie Burrell/Knepp Wildand
Knepp has attracted all the UK's five species of owl. Little owls -- like these -- were introduced to the UK in the 19th century.
Charlie Burrell/Knepp Wildland
Buzzards are the UK's most common bird of prey. This one, soaring above Knepp, feasts on the small mammals and insects that thrive on the estate.
Charlie Burrell/Knepp Wildland
Other predators like foxes help balance the ecosystem by eating a broad diet of rodents, rabbits, birds, frogs and insects as well as berries and fruit.
Charlie Burrell/Knepp Wildland
A grass snake finds a shady spot to hide from predators.
Charlie Burrell/Knepp Wildland
Despite initial skepticism from some members of the local community, Knepp has succeeded in winning over its neighbors and providing a model of farming that supports nature. These Tamworth pigs look very happy.