Area: 42.71 hectares.
Description and Reasons for Notification:
The Carrick Heaths comprises ten sites, all situated within a 12 km radius of Truro. The underlying soils at each site are largely derived from slatey mudstones, siltstones and shales which have given rise to clay soils with variable drainage regimes. These conditions have led to the development of mosaics of wet and dry heathland vegetation types, characterised by populations of Dorset heath Erica ciliaris, a nationally rare plant species and a prime constituent of Southern Atlantic Wet Heath, an internationally important vegetation type. Other noteworthy species recorded include the nationally scarce yellow centaury Cicendia filiformis and Cornish moneywort Sibthorpia europea. Royal fern Osmunda regalis, the rare hybrid Erica watsonii and upright hedge bedstraw Galium album are also all of note. Nationally scarce moss and liverwort species respectively include Brachythecium mildaenum and Warnstorfia sarmentosum.
Areas of heath are characterised by purple moor-grass Molinia caerulea tussocks. The main associates are black bog-rush Schoenus nigricans and Dorset heath, with some cross-leaved heath Erica tetralix also present. The wettest areas are often characterised by abundant bog moss Sphagnum species, frequent sedges such as green-ribbed sedge Carex binervis, common yellow-sedge C. demissa and carnation sedge C. panicea and rushes such as soft rush Juncus effusus and sharp flowered rush J. acutiflorus.
The rushes and the purple moor-grass form low hummocks which support many other wetland herbs such as devil’s-bit scabious Succisa pratensis, water mint Mentha aquatica, bog asphodel Narthecium ossifragum, common cottongrass Eriophorum angustifolium, greater bird’s-foot trefoil Lotus pedunculatus, marsh thistle Cirsium palustre and cuckoo flower Cardamine pratensis.
Of particular interest are common sundew Drosera rotundifolia, hay-scented buckler-fern Dryopteris aemula, occasional stands of bog myrtle Myrica gale and creeping willow Salix repens and broad-leaved cottongrass Eriophorum angustifolium var. elatius. Bog pondweed Potamogeton polygonifolius and marsh pennywort Hydrocotyle vulgaris are locally abundant in waterlogged runnels between the hummocks along with lesser spearwort Ranunculus flammula, marsh St John’s-wort Hypericum elodes and bog pimpernel Anagallis tenella. Other herbs and grasses recorded include lousewort Pedicularis sylvatica, heath spotted-orchid Dactylorhiza maculata, saw-wort Serratula tinctoria, common milkwort Polygala vulgaris, tormentil Potentilla erecta, and bristle bent Agrostis curtisii. Species more typical of damp grassland include common fleabane Pulicaria dysenterica, tufted vetch Vicia cracca, selfheal Prunella vulgaris and yellow bartsia Parentucellia viscosa.
In drier areas, bell heather Erica cinerea and western gorse Ulex gallii are often co-dominant, in some areas with cross-leaved heath Erica tetralix and in others with heather Calluna vulgaris. Dorset heath can also be found in these areas, but is more abundant on the wetter soils.
Overall habitat and species diversity are increased by further areas of adjoining rush pasture, oak Quercus spp. woodland, streams and willow Salix spp. carr. However, grey willow Salix cinerea, birch Betula pendula, gorse Ulex europaeus, bramble Rubus fruticosus agg. and bracken Pteridium aquilinum are encroaching on heathland in places and need to be contained.
The Carrick Heaths also support a range of characteristic fauna. Invertebrate interest includes the nationally scarce pearl-bordered fritillary Boloria euphroysne and the uncommon moth Pammene obscurana as well as two locally important species of dragonfly – the emperor dragonfly Anax imperator and the broad-bodied chaser Libellula depressa. A range of bird species have also been recorded including willow warbler Phylloscopus trochilus, chiffchaff P. collybita, snipe Gallinago gallinago, woodcock Scolopax rusticola, mallard Anas platyrhynchos, teal Anas crecca, garganey A. querquedula, shoveller Anas clypeata and coot Fulica atra. The Red Data Book listed barn owl Tyto alba has also been recorded from Penstraze Moor.