Acid grassland generally consists of fine-leaved grasses such as common bent and fescues, with typical herbs such as sheep’s sorrel, tormentil and heath bedstraw. Acid grassland flora is sometimes associated with lowland heath and mire communities. This assemblage is commonly found on nutrient-poor, free-draining and acidic soils underlain by the sands of bagshot beds, gravels, sandstones and acid igneous rocks.

Although acid grassland is one of the most extensive semi-natural habitats in the United Kingdom, there are scant data on its true extent. Estimates suggest that there is in excess of 1,200,000 ha of acid grassland in the uplands but in the lowlands there is unlikely to be more than 30,000ha (HMSO 1995). The acid grassland resource in London covers an estimated 1,300 ha, which represents some 4% of the total in lowland Britain.

Acid grassland is widespread throughout London; only six out of the thirty-three London boroughs have no recorded areas of acid grassland. There are several quite extensive areas, particularly in the Royal Parks in west London, the southern part of Epping Forest in north London and Wimbledon Common; but in many boroughs the habitat is limited in extent and highly fragmented.

Richmond upon Thames has the largest total area of acid grassland in Greater London with 580 ha (mostly in Richmond Park). This accounts for almost half of this habitat in Greater London. Croydon has 130 ha of acid grassland, which although the second largest amount in London, is less than a quarter of Richmond’s resource (see Table 1 and the Map). Merton has 109 ha of acid grassland, the third largest area within a London borough. The approximate figures for additional boroughs are also given.

Table 1: Acid Grassland Resource within Greater London