Experts, led by the Wildlife Trusts, said the results of a decade-long survey in England and Wales paint a bleak picture for the water vole which is the UKs most rapidly declining mammal and has been lost from 94 per cent of places where they were once prevalent. But they have also found a healthy population of the animals on reserves and waterways around Cambridgeshire. But the local branch of the Wildlife Trusts found water voles in encouraging numbers in the Middle Level of the Fens where staff and volunteers found widespread signs of their presence. Now the trusts are looking for people to help survey water vole populations and care for their riverside habitat for themselves and other water vole conservation groups. Ruth Hawksley, Wildlife Trust Water for Wildlife officer said: Water voles only live two to three years in the wild and many die over winter, so mild winters allowed more to survive, which might account at least in part for the good numbers found. Wide, grass field margins seem to be important for water vole and similarly refuges on river and ditch banks in the city. Ellie Brodie, senior policy manager for the Wildlife Trusts, says: Water voles are an essential part of our wild and watery places and its very sad that were continuing to witness huge declines of this lovely mammal. The Wildlife Trusts and others are working hard to help bring them back again and care for the places that they need to survive but much more is needed if were going to stop this charming creature disappearing altogether. Huge conservation efforts have been made to ensure a future for the water vole with the Wildlife Trusts and others carrying out river restoration work and reintroductions of this species across the UK. At a local level, these projects appear to have been highly successful - however, these successes are not big enough to reverse the national distribution trends. Habitat loss, water pollution and massive building development have led to declines in the voles since the 1960s, made worse by the arrival of North American mink. The Wildlife Trusts are also calling for the creation of a nature recovery network to help water voles and for landowners to manage river bank habitat sympathetically.