Chris Packham said he had a "great fondness" for Wicken Fen
A 100-year National Trust project which will aim to provide "a green lung" for the East has appointed a children's television presenter as its new patron.
Wicken Fen Vision is a scheme to create a 53 sq km (32.9 sq mile) nature reserve from the existing Wicken Fen.
Former Really Wild Show presenter Chris Packham has been picked as its patron.
The National Trust plans on extending the reserve in Cambridgeshire to the outskirts of Cambridge to re-create a mosaic of fenland habitats.
The presenter said: "I am delighted... I have a great fondness for Wicken Fen, a beautiful nature reserve steeped in history.
"I have taken a keen interest in the development of the Vision for a number of years and passionately believe that the development of landscape scale nature reserves is the way forward in helping to safeguard the long term survival of many of our countries' rare and endangered species."
Threat of extinction
Wicken Fen was the first nature reserve owned by the National Trust when it acquired two acres of land in 1899, a remnant of the Great Fen which once covered much of East Anglia.
Throughout the 20th century, the draining of the Fens meant that Wicken Fen's wildlife came under the threat of extinction.
Because of that, the National Trust created the Wicken Fen Vision in 1999.
Its aim was to buy and return agricultural land to nature conservation, giving existing wildlife space to expand and new species the chance to gradually colonise.
Since the project's launch, otters and water vole have returned and barn owls, hen and marsh harriers are regularly seen over the reserve.
Bitterns, one of the UK's rarest wetland birds, have also nested at Wicken Fen for the first time since the 1930s.