This audit covers areas of unimproved and semi-improved neutral grassland. Traditionally, neutral grasslands were managed as hay meadows or pasture, but today these terms are used rather loosely to describe a variety of grassland types. Generally pastures are grazed for most or all of the year, whilst meadows are allowed to grow through spring and early summer and are then cut during June and July - the cuttings being dried and removed for hay (Hare 1988). In London many grasslands may also be managed for informal recreation or as playing fields.

The principle factors that determine the species composition of neutral grassland are soil type, moisture and management (past and present). Much of London’s neutral grassland is found on London Clay sometimes overlain with the sands and loams of the Claygate Beds. The category of unimproved and semi-improved grassland covers a wide range of communities, from rye-grass leys which are floristically very poor, to traditionally managed ‘old meadow’ communities which are generally rich in species.

Thomas Milne’s map of London (1800) shows much of the area surrounding what was then London (essentially what is now the City of London and the City of Westminster) to be meadows and pastures (Hare 1984). Although the area of neutral grassland has been considerably reduced over the years, it is still relatively widespread throughout London and is a significant habitat type in many outer London Boroughs. The City of London is the only borough that does not have any significant areas of neutral grassland.

There are approximately 11,000 hectares of neutral grassland in London - a considerable area when compared with the meagre acid grassland resource of just 1,200 hectares. Hillingdon has the largest total area of neutral grassland in Greater London with just over 2,000 ha, or 19% of the total for London. Bromley has 1,600 ha (15% of the London total) and Havering has 1,300 ha of neutral grassland (12% of the London total). The approximate figures for remaining boroughs are shown in Table 1 and represented by the Map.

The Southeast England regional biodiversity audit (Wicks & Cloughley 1998) recorded acid and neutral grassland together as one habitat type. The audit also excluded semi-improved neutral grassland. As such it was not possible to compare the two audits and place London’s resource within a regional context.

In a national context, semi-natural grasslands now cover 600,000 hectares in lowland England and Wales (only 11% of the total lowland grassland area) (Fuller 1987). Unimproved (species-rich) grasslands total less than 12,000 ha. The semi-natural grassland resource in Greater London is therefore significant, especially when compared with the remaining resource in the arable eastern counties of England. However, the amount of unimproved (species-rich) neutral grassland in Greater London is, as nationally, a tiny fraction of the national total.