Work has begun on the £5m restoration of a wetlands habitat which has been backed by television naturalist Sir David Attenborough.
Suffolk Wildlife Trust has bought land flanking its Carlton Marshes reserve to create a 1,000 acre (404 hectare) southern gateway to the Broads.
It said it would provide a home to “iconic East Anglian species”, adding the work included a visitors’ centre.
Sir David said the project presented a “unique opportunity” for wildlife.
The 348 acre (140 hectare) land purchase was the biggest in the trust’s 55-year history.
It was funded by a £4m grant from the National Lottery Heritage Fund, while a fundraising appeal raised a further £1m.
Julian Roughton, chief executive of Suffolk Wildlife Trust, said the reed bed, fen and wetland areas would “support some of East Anglia’s iconic species, such as fen raft spider, marsh harrier, bittern and crane”.
Contractors will take six months to create the wetlands.
It involves digging out scrapes – shallow pools suitable for wading birds – and the creation of reed beds.
The trust predicts the reserve, which is in north east Suffolk and close to Lowestoft, will attract 120,000 visitors a year.
Sir David, who is president emeritus of The Wildlife Trusts, said: “England’s wildlife is under great and ever-growing pressures.
“It is vital we restore our land on a landscape scale so it can support more wild plants and animals.”