Area: 390.1 hectares.
Description and Reasons for Notification:
This extensive area of lowland heathland lies between the rivers Piddle and Frome. It has developed on infertile soils derived from Bagshot sands and clays overlain locally with plateau gravels. A small area of heath also occurs on Reading Beds. The site contains one of the largest continuous heathland tracts remaining in Dorset although the heath has been fragmented by forestry plantation and military activity. Many of the typical Dorset heathland species that have become nationally rare through heathland loss are well represented.
A number of different heathland plant communities are present, their occurrence dependent on the soil moisture regime. The freely drained soils that occupy most of the higher ground support dry heath. Here, heather Calluna vulgaris is dominant with dwarf gorse Ulex minor, bell heather Erica cinerea and bristle bent Agrostis curtisii frequent. Where drainage is impeded, usually on lower ground, wet heath has developed on seasonally waterlogged soils. Small differences in soil moisture conditions in these areas determine the proportions of cross-leaved heath Erica tetralix, purple moor-grass Molinia caerulea, heather, deergrass Trichophorum cespitosum and the bog mosses Sphagnum compactum and S. tenellum within the vegetation with increasing wetness favouring cross-leaved heath over heather.
The site is intersected by three valley systems, two of which drain southwards to the Frome and one northwards to the Piddle. In the wettest areas along the valley bottoms, in hollows or ‘perched’ bogs further up-slope, soils are permanently waterlogged and valley mire communities have developed on peat. These communities are floristically rich. Bog asphodel Narthecium ossifragum and several species of bog moss Sphagnum spp. are locally abundant including S. papillosum and the very restricted S. pulchrum. White beak- sedge Rhynchospora alba and both Oblong-leaved and round-leaved sundew Drosera intermedia and D. rotundifolia are particularly associated with the margins of the bog pools. Many areas are transitional between valley mire and wet heath vegetation types and these are important for two nationally scarce plants, marsh gentian Gentiana pneumonanthe and brown beak-sedge Rhynchospora fusca.
The bog pools support a number of typical heathland dragonflies including the local small red damselfly Ceriagrion tenellum. Other restricted insects present in suitable habitat within the site include bog bush-cricket Metrioptera brachyptera and silver studded blue butterfly Plebejus argus.
All of Britain’s six native species of reptile breed on the site. The dry heathland and adjacent habitats support several good populations of the two species which are both rare and protected, sand lizard Lacerta agilis* and smooth snake Coronella austriaca*. The dry heath with stands of common gorse Ulex europaeus also provides habitat for the heathland birds stonechat Saxicola torquata and the rare Dartford warbler Sylvia undata+$. Nightjar Caprimulgus europaeus$ breed on the site and wet heath and bog provide important feeding areas for hobby Falco subbuteo+.
*Species listed in Schedule 5 of the Wildlife and Countryside Act 1981. +Species listed in Schedule 1 of the Wildlife and Countryside Act 1981. $Species listed in Annex 1 of the EC Bird Directive.