Area: 29.3 hectares.
Description and Reasons for Notification:
This site includes some of the best examples of semi-natural woodland developed on limestone in Devon. There is a considerable and wide ranging biological interest including the trees and other flowering plants, bryophytes, lichens, birds and invertebrates. Interesting palaeontological discoveries have been made in some of the caves, while the main caves hold important bat roosts.
The main block of woodland occupies a steep-sided valley with other wooded areas on less steep hillsides to the south-west and north-east, all between 30 and 100 metres altitude. Most of the site is underlain by Devonian limestone, but the woodland at the extreme south-west has developed on base-rich shales. On the less steep slopes, generally well drained calcareous clay loam soils occur. There are numerous rock faces in the valley, mostly facing south or south-east, and sheer in places.
The woodland which has grown on the steepest slopes may have originated from a “coppice with pollard” system, with a high canopy and extensive shrub layer and ground flora. Trees on the more exposed rock outcrops are stunted. Some mixed woodland on top of the north-west facing side of the valley has been planted but nevertheless contains a significant proportion of native species and rich ground flora, while the woods to the south-west and north-east all have a semi-natural structure.
The trees forming the canopy are a mixture of pedunculate oak Quercus robur, ash Fraxinus excelsior, field maple Acer campestre, small leaved lime Tilia cordata, wych elm Ulmus glabra and wild cherry Prunus avium, with some wild service-tree Sorbus torminalis, a local species. A wide variety of native shrub species form the understorey. The ground flora throughout is herb-rich and luxuriant, and includes many of the species typically associated with woodland on calcareous soils, such as woodruff Galium odoratum, yellow archangel Lamiastrum galeobdolon and stinking iris Iris foetidissima. Of particular note are ivy broomrape Orobanche hederae and toothwort Lathraea squamaria.
The saxicolous lichens and bryophytes which grow on the rocks, particularly where they are shaded, are of regional significance and include Caloplaca cirrochroa, Dermatocarpon miniatum and Verrucaria coerulea. A number of epiphytic species associated with ancient woodland such as Catinaria grossa, Phlyctis agelaea andSchismatomma virgineum are found here also.
The caves provide important roosts for the greater horseshoe bat Rhinolophus ferrumequinum. The breeding woodland bird community includes buzzard Buteo buteo and raven Corvus corax. The site has a rich invertebrate fauna, including the slug Boetigerilla pallens which is restricted to this site in Devon, hornet Vespa crabro and the white admiral butterfly Ladoga camilla.