Area: 39.5 hectares.
Description and Reason for Notification:
This site contains a nationally rare and distinctive type of habitat mosaic, consisting of various herb-rich grassland and heath communities. The majority of vegetation types typical of the Culm Measures of North Devon and north-east Cornwall are represented in this unusually diverse area.
Stowford and Mambury Moors are located in north Devon on Upper Carboniferous sandstone of the Bude formation which forms a major part of the Culm Measures. The soil is slowly permeable, seasonally waterlogged clay. The site lies at 150–170 m above sea level.
The main plant communities present reflect the impeded drainage. One of these is a type of fen meadow, with abundant purple moor-grassMolinia caerulea, devil’s-bit scabious Succisa pratensis and meadow thistle Cirsium dissectum, and a range of sedges, including carnation sedge Carex panicea, flea sedge C. pulicaris and tawny sedge C. hostiana. Heath spotted-orchid Dactylorhiza maculata is frequent here. The particular variant of this community represented here, characterised by cross-leaved heath Erica tetralix, is almost wholly confined to the Culm Measures of Devon and Cornwall.
Another grassland community is dominated by purple moor-grass Molinia caerulea tussocks, with frequent marsh thistle Cirsium palustre and wild angelica Angelica sylvestris.
Wet heathland is also well represented with areas dominated by western gorse Ulex gallii, heather Calluna vulgaris and cross-leaved heath Erica tetralix. Petty whin Genista anglica, a very local plant in Devon, occurs here.
In the wettest areas, bottle sedge Carex rostrata beds are found, with bogbean Menyanthes trifoliata and marsh cinquefoil Potentilla palustris, both uncommon plants in Devon, and also the nationally scarce wavy St John’s-wort Hypericum undulatum.
The fauna of the site has not been fully surveyed, but it is known to be of entomological importance, with the local marsh fritillary butterfly Eurodryas aurinia and a very strong colony of the marbled white Melanargia galathea butterfly.