Purple moor grass and rush pastures

Padley Common - part of Chagford Commons is an area of purple moor grass and rush pasture

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 (Molinia caerulea) and one or more of several creeping rushes: sharp-flowered rush (Juncus acutiflorus), jointed rush (Juncus articulatus) and blunt-flowered rush (Juncus subnodulosus).

Only 8% remains of the area thought to have existed in 1900. In the UK estimate the area is thought to be less than 70,000 hectares (170,000 acres).[1] 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.[1] In East Anglia it is known as litter meadow due to the practice of cutting it for bedding.[1] In Wales it is known as rhôs pasture.[1]

Typical grasses

Common bent (Agrostis capillaris), crested dog's-tail (Cynosurus cristatus), floating sweet grass (Glyceria fluitans), marsh foxtail (Alopecurus geniculatus), purple moor grass (Molinia caerulea), red fescue (Festuca rubra), sweet vernal grass (Anthoxanthum odoratum).[2]

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.[2]

Key animal species associated with purple moor grass and rush pastures

  • Marsh fritillary butterfly (Eurodryas aurinia), uses scattered scrub and carr in September/October.
  • Brown hairstreak (Theccla betulae)
  • Narrow-bordered bee hawkmoth (Hemaris tityus) - fly during April/May, during the day.
  • Eurasian curlew (Numenius arquata) - lays eggs in April/May in open ground on a mound or tussock, incubates them through to June, and young may not be ready to fly until late July or into August.
  • Common snipe (Gallinago gallinago)
  • Barn owl (Tyto alba)
  • Marbled white (Melanargia galathea) on the wing in June/July.
  • Reed bunting (Emberiza schoeniclus) uses scattered scrub and carr in September/October.

British National Vegetative Classification

The main British National Vegetation Classification communities associated with purple moor grass and rush pastures include M23 (Juncus effusus/acutiflorus-Galium palustre rush pasture), M25 (Molinia caerulea-Potentilla erecta mire), M26 (Molinia caerulea-Crepis paludosa mire) and British NVC community MG10 (Holco-Juncetum effusi rush-pasture).

Threats

Management

Natural England Guidance advocates an average grass height of 7 and 8 centimetres (2.8 and 3.1 in) for rush during April and May, increasing to 10 and 13 centimetres (3.9 and 5.1 in) in June to October, a quarter of the sward no more than 15 centimetres (5.9 in) for grass and 40 centimetres (16 in) for rushes - a diverse sward of shorter areas interspersed by taller tussocks.[3]

Areas of dense litter are beneficial to overwintering 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.[4][5]

References

  1. ^ a b c d "Purple moor-grass and rush pasture". English Nature (succeeded by Natural England). 2004. Archived from the original on 2011-07-10. Retrieved 2010-08-13.
  2. ^ a b "NE264 - Higher Level Stewardship Farm Environmental Plan". Natural England. March 2010. Archived from the original on 2011-07-10. Retrieved 2010-08-13.
  3. ^ 29-31[permanent dead link‍]
  4. ^ "Reserves - Rackenford and Knowstone Moor - Overview". Devon Wildlife Trust. Archived from the original on 6 January 2014. Retrieved 5 January 2014.
  5. ^ "Reserves - Rackenford and Knowstone Moor - More info". Devon Wildlife Trust. Archived from the original on 6 January 2014. Retrieved 5 January 2014.
  • Magic mapping system showing purple moor grass and rush pasture locations in the UK