MORE than half of Dorset's historic treasures are at high risk from neglect or decay, according to a new register launched today.

The catalogue is contained in English Heritage's new national Heritage at Risk register.

English Heritage south west regional director Andrew Vines said the area had 3,988 out of 6,958 scheduled monuments at risk from damage, decay or loss unless action was taken.

"The main threats to our scheduled monuments are ploughing for arable crops and invasive plant growth.

"Significant numbers of monuments are also at risk from erosion by livestock, neglect, vandalism and animal burrowing.

"Damaged or lost scheduled monuments cannot be replaced and careful management is required if we are to pass them on to future generations."

The register includes sites such as the Ridgeway barrow group, an extensive prehistoric cemetery which stretches across the South Dorset Ridgeway north of Weymouth. It has 18 scheduled monuments including examples of Neolithic long and bank barrows as well as Bronze Age round barrows.

English Heritage said that much of the Ridgeway has been under arable cultivation for many years and nine of the scheduled monuments were deemed to be at high risk from ploughing activities.

A higher level stewardship scheme agreed with the land holder will stop ploughing on the most important and best preserved of the monuments which will revert to pasture, said the group.

The new register extends English Heritage's existing Buildings at Risk record for Grade I and Grade II listed sites.

It will eventually include Grade II buildings, 19,709 scheduled monuments, archaeology, historic landscapes, parks and gardens, places of worship, conservation areas, battlefields and designated maritime wrecks.

Other Dorset sites mentioned on the register include Weymouth's Grade I listed Sandsfoot Castle built by Henry VIII.

English Heritage said it was built on soft clays and suffers from ongoing erosion and instability.

The former 1818 Methodist chapel at Tolpuddle, the meeting place of the Tolpuddle Martyrs, also appears in the register.

English Heritage said talks were going on to find a possible commercial use for the building while the local authority had power to serve an Urgent Works Notice on the structure.

Portland's 15th century Rufus Castle gets a mention as being ruinous and in need of conservation repair and consolidation'.

The owner is working up a repair scheme, emergency repairs have been completed to stabilise collapsing masonry and an English Heritage grant has been offered for the main repair scheme.

Also detailed is the late 16th century Wolfeton Manor Riding School near Charminster, one of the oldest surviving riding schools in England.

It is currently used as a barn, was recently passed to a trust and is awaiting major repairs with temporary roof repairs undertaken using English Heritage grant aid. English Heritage said the future of the building remains uncertain' despite a feasibility study being completed.

Other sites mentioned include Maiden Street Methodist Church in Weymouth, the remains of St Mary Magdalene Church in North Wootton and Sherborne House.

Others are the Church of St Peter on Portland, St Giles House and grotto at Wimborne St Giles, the remains of medieval buildings at Witchampton, Sturminster Newton Castle.

Marshwood Castle, North Lodges at Lulworth Castle, Manor Farm Barn at Winterborne Clenston, a barn and outbuildings at Tarrant Crawford and the Literary and Scientific Institute at Bridport are also in the list.

English Heritage chief executive Dr Simon Thurley said: "We hope that our Heritage At Risk register will galvanise the nation into action before it is too late and help us save the best of the past for the future."