Area: 30.8 hectares.
Description and Reasons for Notification:
The south-facing cliffs west of Portwrinkle are particularly important for several rare plant species that occur within the mainly scrub dominated cliff slopes and coastal margin.
The site extends for about 3 kilometres along the south Cornish coast between Long Stone Rock and Portwrinkle. The cliffs are steeply rising to a height of 100 metres in places, and are composed of Dartmouth slates of Lower Devonian age. There are active landslides on several stretches. Soils are naturally well-drained loams, but stony and shallow over harder rocks.
The cliff face is dominated by dense scrub consisting of blackthorn Prunus spinosa, European gorse Ulex europoroeus with patches of bracken Pteridium aquilinum, bramble Rubus fruticosus and honeysuckle Lonicera periclymenum. Along the base of the cliff rock crevice vegetation occurs with thrift Armeria maritima, sea campion Silene maritima, English stonecrop Sedum anglicum and buck’s-horn plantain Plantago coronopus being common.
Maritime grassland occurs in small areas along the cliff edge, thrift Armeria maritima, red fescue Festuca rubra, wild carrot Daucus carota and sea campion Silene maritima being dominant. Areas of unimproved neutral grassland occur to the east with species such as creeping soft grass Holcus mollis, cock's-foot Dactylis glomerata, sweet vernal-grass Anthoxanthum odoratum and Yorkshire fog Holcus lanatus.
The cliffs are particularly important for the occurrence of two Red Data Book* plant species: the slender bird’s-foot trefoil Lotus angustissimus and carrot broomrape Orobanche maritima. The clustered clover Trifolium glomeratum, a nationally rare species, has also recently been found here. In addition, some 44 species of moss have been recorded along this coastal stretch, including Tortula atrovirens and Fissidens bambergeri which are local on the south coast and rare elsewhere.
The butterfly species including grayling Hipparchia semele and dark green fritillary Argynnis aglaja both of which are nationally declining species.
Some twenty-two pairs of breeding shag Phulacrocorax aristotelis have been recorded on the cliffs.
* The British Red Data Book – vascular plants documents rare and endangered species.