Purple moor grass and rush pastures


Purple moor grass and rush pastures is a type of Biodiversity Action Plan habitat in the UK. It occurs on poorly drained neutral and acidic soils of the lowlands and upland fringe. It is found in the South West of England, especially in Devon.
The vegetation consists of species-rich, semi-natural grassland containing abundant purple moor grass and one or more of several creeping rushes: sharp-flowered rush, jointed rush and blunt-flowered rush.
Only 8% remains of the area thought to have existed in 1900. In the UK estimate the area is thought to be less than. Their importance is recognised and are included as a priority habitat in the United Kingdom Biodiversity Action Plan.

Etymology

In Devon and Cornwall it is known as culm grassland, after the Culm Measures on which it is predominantly found. In East Anglia it is known as litter meadow due to the practice of cutting it for bedding. In Wales it is known as rhôs pasture.

Typical grasses

Common bent, crested dog's-tail, floating sweet grass, marsh foxtail, purple moor grass, red fescue, sweet vernal grass.

Characteristic species

The Natural England Higher Level Stewardship Farm Environmental Plan handbook defines the habitat as grassland with at least two of the following species are found frequently, with another two being found occasionally.
The main British National Vegetation Classification communities associated with purple moor grass and rush pastures include M23, M25, M26 and British NVC community MG10.

Threats

Natural England Guidance advocates an average grass height of for rush during April and May, increasing to in June to October, a quarter of the sward no more than for grass and for rushes - a diverse sward of shorter areas interspersed by taller tussocks.
Areas of dense litter are beneficial to over-wintering insects and small mammals, but should be less than 25% of the total area in October.

Protection

In the UK there are a number of initiatives to help prevent deterioration and to restore these sites. These include designation as Site of Special Scientific Interest, national nature reserves, voluntary entry into the Environmental Stewardship Scheme by landowners, or work by voluntary conservation organisations such as the Devon Wildlife Trust. The largest area of Culm grassland in Devon is Hare's Down, Knowstone & Rackenford Moors near Rackenford and is owned by Devon Wildlife Trust. Their management regime includes controlled burning in winter and light grazing by cattle in the summer. The aim is to control the amounts of scrub and bracken without removing them completely.