Area: 175.09 hectares.
Higher Hyde Heath is managed as a nature reserve by the Dorset Wildlife Trust.
The site was formerly notified as part of Hyde Heath SSSI. Hyde Heath has now been split with the area north of the River Piddle becoming part of Morden Bog and Hyde Heath SSSI, whilst the area south of the River Piddle becomes Stokeford Heaths SSSI at this notification.
Description and Reasons for Notification:
Stokeford Heaths is one of a collection of sites which together comprise the Dorset heathlands. Although these heathlands have declined in extent and now occupy only 14% of their original area they show a high degree of ecological cohesion and clear ecological trends and patterns. This complex is one of the major lowland heathland areas in Britain and is of international importance for its plant and animal communities.
Stokeford Heaths consists of several heathland fragments occupying a ridge of high ground (up to 60 metres) between the rivers Piddle and Frome. The ridge is formed from sands and clays of the Bagshot Beds overlain with plateau gravels. The original heathland area has been reduced in extent and fragmented by the quarrying of these deposits. The site is important for its heath and mire plant communities and for the many rare and scarce species associated with the heath and mire.
The topography is complex. Several valleys cut into the ridge and lead down to the two main river valleys. In addition, there are areas where heathland has developed on the humps and hollows created by old surface mineral workings.
A range of heath and mire plant communities is present. Soil moisture is the main factor that determines their distribution. In many places the vegetation shows the classic transition moving downslope from dry heath through humid and wet heath to mire.
Dry heathland is the predominant vegetation type on well drained sands and gravels. The community is dominated by heather Calluna vulgaris with bell heather Erica cinerea, dwarf gorse Ulex minor and locally bristle bent Agrostis curtisii. Where there is slight impedance of drainage dry heath grades into humid heath. Here heather is usually still dominant but cross-leaved heath Erica tetralix and purple moor-grass Molinia caerulea are common associates with dwarf gorse and bristle bent. The national distribution of this vegetation type is extremely restricted; occurring only in the New Forest and Dorset.
Where drainage is more severely impeded and soils at least seasonally waterlogged, wet heath communities occur on shallow peat with cross- leaved heath and purple moor-grass typically the most abundant species. Deergrass Trichophorum cespitosum and two species of bog moss, Sphagnum compactum and S. tenellum are also characteristic plants of this community.
Several types of mire community occur locally on permanently wet peat. In one type, purple moor-grass and cross-leaved heath are again common but are found with bog asphodel Narthecium ossifragum, several bog mosses including Sphagnum papillosum and the nationally scarce S. pulchrum, white beak-sedge Rhynchospora alba and common cottongrass Eriophorum augustifolium. A number of other distinctive plants also occur in this community and these include round-leaved sundew Drosera rotundifolia, early marsh-orchid Dactylorhiza incarnata and pale butterwort Pinguicula lusitanica. This is a rare and species-rich plant community with a restricted national distribution.
Locally this community grades into a second type of mire vegetation where purple moor-grass is typically abundant forming large tussocks. In these areas there is often pronounced lateral movement of groundwater and bog myrtle Myrica gale can form dense stands. Tormentil Potentilla erecta is a characteristic plant of these locations.
A number of small pools occur within the mires and these support two more bog mosses S. cuspidatum and S. auriculatum. Elsewhere, mire vegetation is replaced by wet woodland dominated by sallow Salix species with an understorey of purple moor-grass. The local Royal fern Osmunda regalis is found in these areas.
In several places the site includes areas of former gravel workings which have been abandoned as a series of small ridges, gulleys and hollows. Dry heath has developed on the ridges with the wetter heath communities in the gulleys and hollows. Also in the hollows are a number of pools, both permanent and seasonally wet, which support marsh St. John’s-wort Hypericum elodes and the local shoreweed Littorella uniflora.
The heath and mire communities provide a habitat for a number of nationally rare and scarce plant and animal species. The nationally rare Dorset heath Erica ciliaris occurs in a single locality, near the edge of its range on the Dorset heaths. Nationally scarce plants are represented by three species: marsh gentian Gentiana pneumonanthe is found in wet heath in several different locations, bog orchid Hammarbya paludosa is found within one valley mire, and a large population of marsh clubmoss Lycopodiella inundata occurs within an old and partly revegetated quarry. The marsh clubmoss population is the largest in Dorset and amongst the largest nationally of a species that has shown a substantial recent decline.
The site is important for a number of invertebrate species and species groups. At least 17 breeding dragonfly species have been recorded including three which are nationally scarce. These are small red damselfly Ceriagrion tenellum, downy emerald Cordulia aenea and scarce blue-tailed damselfly Ischnura pumilio. Grasshoppers and crickets are also well represented with three rare and scarce species recorded: large marsh grasshopper Stethophyma grossum (Red Data Book vulnerable) is found within one valley mire; heath grasshopper Chorthippus vagans (Red Data Book rare) has been recorded from dry heath and the nationally scarce bog bush cricket Metrioptera brachyptera is widespread throughout the site. Other notable invertebrates include a colony of the ant Formica transkaucasica (Red Data Book endangered), a species restricted to a small number of valley mires in Dorset and the New Forest. Several colonies of the nationally scarce butterfly silver-studded blue Plebejus argus are also present.
The site supports important populations of two endangered and protected reptiles; sand lizard Lacerta agilis2 and smooth snake Coronella austriaca2. These occur in a number of different locations throughout the site including areas of revegetated surface workings and on isolated sites within conifer plantations. The site is estimated to support between 3 and 4% of the national population of sand lizards.
There is considerable bird interest with both the range of breeding species and a number of individual rare species being important. Dry heathland on the site supports approximately 1% of the national breeding population of the rare Dartford warbler Sylvia undata1,3. The site is also a stronghold for nightjar Caprimulgus europaeus1, making a substantial contribution to the internationally important nightjar population of the Dorset heaths. Other birds of interest which breed on the heath are tree pipit Anthus trivialis and stonechat Saxicola torquata while snipe Gallinago gallinago breed on one of the valley mires. The site forms part of a breeding territory of hobby Falco subbuteo3, the rare woodlark Lullula arborea1,3 is also regularly recorded from the site.
1Species listed in Anne 1 of the EC Birds Directive.
2European protected species listed in Schedule 2 of the Habitats Regulations 1994.
3Specially protected species listed in Schedule 1 of the Wildlife and Countryside Act 1981.