Cefn y Brithdir

Site of Special Scientific Interest · 51.7231, -3.2548

Also within

Gwent County

Description

Description Cefn y Brithdir is a hill of Pennant grit, situated on the western side of the upper Rhymney Valley overlooking the town of New Tredegar. The steep north-eastern slopes support the best example in Mid Glamorgan of a dwarf shrub heath community in which crowberry Empetrum nigrum occurs as a co-dominant species. A range of dry heath species are found on the site. Crowberry is associated with bilberry Vaccinium myrtillus. Heather Calluna vulgaris grows around the crags and rocky outcrops where grazing is less intense. Grasses include wavy hair-grass Deschampsia flexuosa, sheep's-fescue Festuca ovina and mat-grass Nardus stricta.The diversity and relative density of the dwarf shrub species present on this site is unusual in Mid Glamorgan. Crowberry is here close to the southern edge of its range in Britain.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
Phalacrocorax aristotelis Not listed in GB list bird phalacrocoracidae
wavy hair grass Deschampsia flexuosa Not listed in GB list grass poaceae
sheep's fescue Festuca ovina LC grass poaceae
mat grass Nardus stricta LC grass poaceae
bell heather or ling Calluna vulgaris NT shrub dwarf ericaceae
crowberry Empetrum nigrum LC shrub dwarf empetraceae

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

SpeciesStatusVia host-plant
Shoulder-striped clover
Heliothis maritima
Endangered Calluna vulgaris
Broom moth
Ceramica pisi
Vulnerable Calluna vulgaris
Satyr pug
Eupithecia satyrata
Vulnerable Calluna vulgaris
Grayling
Hipparchia semele
Vulnerable Festuca ovina
True lover's knot
Lycophotia porphyrea
Vulnerable Calluna vulgaris
Silver studded blue
Plebejus argus
Vulnerable Calluna vulgaris
Hedge rustic
Tholera cespitis
Vulnerable Nardus stricta
Pale eggar
Trichiura crataegi
Vulnerable Calluna vulgaris
Flounced chestnut
Agrochola helvola
Near Threatened Calluna vulgaris
Small heath
Coenonympha pamphilus
Near Threatened Festuca spp., Nardus stricta
Rosy marsh moth
Coenophila subrosea
Near Threatened Empetrum nigrum
Grey scalloped
Dyscia fagaria
Near Threatened Calluna vulgaris
Small mountain ringlet
Erebia epiphron
Near Threatened Nardus stricta
Autumnal rustic
Eugnorisma glareosa
Near Threatened Calluna vulgaris, Festuca ovina
Silver-spotted skipper
Hesperia comma
Near Threatened Festuca ovina
Weaver's wave
Idaea contiguaria
Near Threatened Calluna vulgaris, Empetrum nigrum
Rosy minor
Litoligia literosa
Near Threatened Festuca ovina
Scotch burnet
Zygaena exulans
Near Threatened Empetrum nigrum

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.