MANAGERS of one of the North-East's most important wildlife sites have called in some hardy volunteers to help with vital conservation work.

Rare Exmoor ponies have been brought in at the National Nature Reserve close to Thrislington Quarry, near Ferryhill, County Durham.

The ponies are being used to eat an unwelcome species of grass growing at Thrislington Plantation.

The 23-hectare reserve is jointly managed by construction materials company Lafarge Aggregates and English Nature.

An important part of managing the reserve is to protect the European species, blue moor grass, from being overwhelmed by a variety called upright brome.

Finding animals to graze on the brome has been difficult as most sheep refuse to touch this particularly coarse grass. But now an Exmoor pony owner from County Durham has loaned some animals for winter grazing.

John Hope, of English Nature, said: "The Exmoor pony can graze as short as sheep and likes eating the tough upright brome."

Thrislington Plantation, which was first designated as a Site of Special Scientific Interest in the 1960s, is home to 21 species of butterfly and nine varieties of orchid.