Area: 1,226.7 hectares, 3,031.1 acres.
A substantial part of this site is within M.O.D. firing ranges. Site boundary amended by extension/deletion.
Description and Reasons for Notification:
A substantial tract of heathland with bordering grasslands and woodland. Most of the heathland is damp or wet including some well developed bog systems, but there are also areas of dry heath. The heathland has a rich associated fauna. The peripheral grasslands which vary in wetness are acidic or neutral in character and several fields possess uncommon and very diverse plant communities.
Although severely reduced in area by afforestation, dry heath occurs on the higher ground and is dominated by ling Calluna vulgaris with bell heather Erica cinerea and bristle bent Agrostis curtisii. Common gorse Ulex europaeus is scattered, bracken Pteridium aquilinum is locally frequent and there are stands of self-sown Scots pine Pinus sylvestris and maritime pine Pinus pinaster. However, the heathland over the Bagshot Beds is mainly humid or wet with varying proportions of ling, cross-leaved heath Erica tetralix and purple moor-grass Molinia caerulea. Some areas of wet heath, especially where grazed, support rich plant communities with high proportions of meadow thistleCirsium dissectum, the sedges Carex panicea and C. demissa, sundews Drosera rotundifolia and D. intermedia, marsh- and heath-spotted orchids Dactylorhiza incarnata and D. maculata, and locally the rare marsh gentian Gentiana pneumonanthe and marsh clubmossLycopodiella inundata. The wettest areas on the Bagshot Beds have well developed bog communities with a variety of Sphagnum species including the rare S. pulchrum, white beak-sedge Rhynchospora alba, cotton-grass Eriophorum angustifolium, bog bean Menyanthes trifoliata, bog myrtle Myrica gale, bog pondweed Potamogeton polygonifolius and the very local great sundew Drosera anglica. Where slightly more base-rich water conditions prevail as in the bog on the edge of the Frome Valley, the usual bog vegetation is supplemented by species such as reed Phragmites australis and black bog-rush Schoenus nigricans.
In places, especially on the London Clay on the edges of the heathland, there is wet acidic grassland. This includes many of the species found on the richer areas of wet heath with meadow thistle often particularly abundant but is grass- dominated and heathers are absent or uncommon. Typical plants of these swards include bent grasses Agrostis spp., quaking grass Briza media, heath grass Danthonia decumbens,flea sedge Carex pulicaris, devil’s-bit Succisa pratensis, saw-wort Serratula tinctoria, lousewort Pedicularis sylvatica, petty whin Genista anglica, sneezewort Achillea ptarmica and the moss Calliergoniella cuspidatum. Deciduous woodland, mainly of birch Betula sp. and Sallow Salix cinerea, is most frequent on the banks of streams but woodland dominated by pedunculate oak Quercus robur occurs on the London Clay in the south of the site. Scrub communities are a feature of this area and typically are dominated by blackthorn Prunus spinosa.
As might be expected, this large area of varied habitat holds a rich fauna. The heathland particularly supports a number of rare species in consequence of the rarity of the habitat itself. The bog pools and flushes support an impressive number of dragonflies including the very restricted small red damselfly Ceriagrion tenellum and scarce ishnura Ishnura pumilio. Grasshoppers and bush-crickets are also well represented. The larger bogs hold the rare large marsh grasshopper Stethophyma grossum and the wet heath long-winged conehead Conocephalus discolor, another very local insect. The extremely restricted heath grasshopper Chorthippus vagans occurs on the dry heath in its most westerly known site in Britain. The dry heath also supports important populations of the rare reptiles, the sand lizard Lacerta agilis and smooth snake Coronella austriaca. However, because of extensive conifer planting, dry heathland is much reduced from its original extent and populations of animals of dry heath are similarly limited. The site is also very important for breeding birds. It is an important site for the rare Dartford warbler Sylvia undata and other restricted heathland birds include nightjarCaprimulgus europaeusand hobby Falco subbuteo. The thorn scrub holds one of the most important breeding populations of nightingale Luscinia megarhynchos in Dorset.