RESEARCH into the remote caves and mineshafts of the Yorkshire Dales has uncovered thousands of roosting bats never before found in the region.

A team of university experts has provided vital new information on the importance of the Dales' underground, which was previously thought to be little used by the North's bat populations.

Earlier studies of the area had found hardly any evidence of bats using roosting sites in the extensive network of caves and mines.

But high-tech investigations carried out at night by Leeds University ecologists have uncovered thousands of bats visiting new sites.

Professor John Altringham, whose team is also studying bat populations on the North York Moors, said previous studies had relied on visual surveys for roosting bats and only a few bats had ever been found.

But he added: "Our recent night-time surveys, using humane traps, bat detectors and night-vision equipment are painting a very different and more accurate picture, with tens, hundreds or even thousands of bats visiting roosting sites previously thought to be unimportant.

"By taking a different approach to survey work, the assumptions of the past are having to be re-thought."

As well as spotting the five cave-roosting species known to be resident in the North, the research team has also found noctule bats, a species not normally associated with caves.

Dr Tim Thom, an ecologist at the Yorkshire Dales National Park Authority, said: "Until recently, it was believed that the caves and mineshafts of the area were little used by the area's bat populations.

"Yet the latest research from the University of Leeds team is proving this to be very wrong."

The research has prompted the authority to draw up a caves habitat action plan, which will ensure that caves with a high biological importance are properly managed.

Experts will also start working with pot hole clubs to develop voluntary codes of practice for the recreational use of caves.