Magnesian limestone grassland was once much more widespread but over the last sixty years the area of magnesian limestone grassland has sharply declined due to changes in agricultural policies and development pressures. Our remaining magnesian limestone grassland sites in the Durham Magnesian Limestone Natural Area are small and highly fragmented. The extent of habitat-loss of magnesian limestone grassland probably exceeds that of other lowland limestone grasslands in the UK .

The total national resource of magnesian limestone grassland is limited to 279 hectares in the Sites of Special Scientific Interest (SSSI) series. Two-thirds of the national resource is found in east Durham and Tyne and Wear.

The community unique to east Durham and Tyne and Wear, Blue Moor-grass - Small Scabious (Sesleria caerulea - Scabiosa columbaria), is possibly one of the rarest calcareous grasslands in the UK. A survey by English Nature in the 1990s suggested less than 65 hectares of this community remains.