Acid Grassland action plan

Aims
1. To ensure the protection and optimal management of acid grassland in Greater London.
2. To improve on existing knowledge of its ecological value in the regional context.
3. To develop a more universal appreciation of the habitat and its wildlife, and secure the involvement of Londoners in its conservation.



As its name suggests, acid grassland develops over acidic soils. These soils are usually derived from free-draining sands and gravels that are low in nutrients. The habitat generally consists of various fine-leaved grasses and associated wildflowers, such as common bent, red and sheep's fescues, wavy hair-grass, sheep's sorrel, tormentil, cat's-ear and heath bedstraw. This plan also addresses a less widespread type of acid grassland that consists mainly of purple moor-grass and is found where drainage is more impeded.

The soil conditions described above also support dwarf-shrub heathland. Much of today's acid grassland represents a degraded habitat which has lost its characteristic low-growing shrubs, such as heather, to various erosive forces. However acid grassland is an essential part of the habitat mosaic found on heathlands, and it is important to note that the present lack of heather is symptomatic of an imbalance caused by particular circumstances, rather than the undesirable replacement of one habitat by another.

Although acid grassland is a fairly meaningless concept for most people, there is no reason why the finer qualities of the habitat should not gain wider appreciation. Unlike chalk grassland, acid grasslands are not generally celebrated for their wealth of colourful wildflowers, although some of the characteristic species that do occur here are no less charismatic. These include harebell, common stork's-bill, buck's-horn plantain, heath milkwort and the diminutive bird's-foot. Nationally scarce plants found in London's acid grassland include clustered clover, upright chickweed and autumn squill.

The acid grasslands of Greater London, south Essex and north-west Kent appear to be the natural home of a distinctive group of insects and spiders. A combination of factors appears to be responsible for this, including the loose and often bare soil, availability of nectar-rich wildflowers, plus the region's geographic location in the driest corner of the British Isles yet still close to the sea. Prominent within the group are many hole-nesting bees, wasps and ants, such as the rare mining bee Andrena florea. The UK distribution of many species is apparently very restricted and this unique assemblage has been collectively termed the 'Thames Terrace invertebrate fauna'.

More familiar insects frequenting acid swards are the small heath and small copper butterflies, while the hummocks of meadow ants are another common feature. The fungi found here may also be interesting. Associated birdlife includes the meadow pipit, skylark and, attracted by the rich insect pickings, the green woodpecker.

Contact
The Lead for this habitat is the Royal Parks Agency.
Nigel Reeve
Royal Parks Agency
Holly Lodge
Richmond Park
London

Email: [email protected]