A decline in rare butterflies on Farthing Downs in Coulsdon has been successfully stemmed by a pilot cattle grazing scheme, new research by butterfly conservationists has revealed.

After counting specialist habitat-dependent butterfly species and comparing their numbers in a variety of sites, charity Butterfly Conservation found up to 10 out of 13 species had done better on the Downs and other sites, where similar "agri-environmental" schemes had been introduced.

The pilot's success will lead to more butterfly conservation work countrywide. Butterfly conservationist and site superintendent Mike Enfield, explained: "The grazing creates a mosaic of short and long grasses which provides an ideal habitat for a number of butterfly species.

"The land is also accessible to the public, and hopefully on nice summer days, when the flowers are in full bloom, visitors get to see the butterflies, such as Gatekeepers, the popular Meadowbrown and Common Blues."

The herd of grazing cattle was maintained with funding from DEFRA (Department for the Environment, Food and Rural Affairs), under Countryside Stewardship and Environmentally Sensitive Areas schemes.

A DEFRA spokesman said the conservationists' dataset is possibly the largest in the world tracking the abundance of an insect group.

Data was collated using specially designed software known as Transect Walker that allows local recorders to enter and analyse their own data.

The research, which will be extended for another three years, will continue to provide information vital to the development of the schemes and other biodiversity objectives. The Millennium Atlas of Butterflies in Britain and Ireland, recently produced by Butterfly Conservation and the Biological Records Centre, shows that over half of Britain's 59 resident species have declined seriously over the last 150 years and five species have become extinct.