Area: 14.7 hectares.
Description and Reasons for Notification:
Small Brook is important for its traditionally managed, oceanic, acidic grassland, mire and fen meadow communities. Collectively these communities are known as Culm Grassland, a wildlife habitat which is becoming increasingly rare throughout western Britain. The site is of particular importance for its fen meadow communities, which are especially species-rich.
The site comprises five fields situated on either side of a stream overlying the Carboniferous shales of the Culm Measures of north Devon, about 3 km north-west of Holsworthy. The soils are acidic clays with restricted or poor drainage, on gently sloping ground.
The site supports an extensive area of species-rich purple moor-grass Molinia caerulea sward with abundant meadow thistle Cirsium dissectum, devil’s-bit scabious Succisa pratensis, carnation sedge Carex panicea and whorled caraway Carum verticillatum, a species which is virtually confined in England to north-west Devon. Other associated species include saw-wort Serratula tinctoria, greater bird’s-foot trefoil Lotus pedunculatus and heath spotted orchid Dactylorhiza maculata.
In places there is a distinct heathy element to the sward with species such as lousewort Pedicularis sylvatica, cross-leaved heath Erica tetralix, flea sedge Carex pulicaris, star sedge C. echinata, tawny sedge C. hostiana and the locally uncommon petty whin Genista anglica.
Local surface water movement gives rise to patches of soft-rush Juncus effusus, with marsh violet Viola palustris and the nationally scarce wavy St John’s-wort Hypericum undulatum, a species found in England only in Devon and Cornwall.
There is a small area of unmanaged mire at the western end of the site with tall purple moor- grass tussocks, showing bramble Rubus fruticosus and other scrub invasion.
The nationally scarce marsh fritillary butterfly Eurodryas aurinia is present.