ANCIENT monuments which date back to pre-historic times, are being threatened in the North York Moors National Park – by badgers.

A number are in the Forestry Commission plantations and are at risk because they contain badger setts, says Mags Waughman, the park's monuments scheme officer.

"Badgers can disturb large quantities of soil and damage fragile archaeological deposits but because they are a protected species we need to balance the needs of the archaeology with nature conservation."

The park's historic environment volunteers have now been trained in how to recognise badger activity, said Ms Waughmanin the park's latest report.

"So far the badgers haven't brought any artefacts to the surface."

However the monuments also have another enemy, she said - bracken. "It is a particular problem because of the way it develops and spreads. It can cause enormous damage to fragile deposits and features below the ground surface."

Organising the treatment and control of the bracken growing on scheduled monuments has been a big of a project by the National Park in a joint scheme with English Heritage, known as the Monument Management Scheme (MMS).

Monuments from Bronze Age burial mounds and prehistoric field systems to medieval rabbit warrens have needed attention and so far 37 have been cleared and renovated.

The park has the largest number of ancient monuments in Yorkshire - 840. As a result of the MMS scheme the number which were officially listed as being "at risk" by English Heritage has been halved from 198, and the number is expected to reduce to 50 in a year's time, said Ms Waughman.