Odstock Down

Site of Special Scientific Interest · 51.0237, -1.8039

Condition (Natural England)

Unfavourable Recovering (1)
UnitFeatureConditionArea (ha)Assessed
SU138249 Unfavourable Recovering 12.82 2010-06-17

Geology & landscape

Rock Type: Chalk

Description

Area, 12.l ha. 29.9 ac. Description Odstock Down is a floristically diverse area of chalk grassland typical of the South Western chalk. The turf is chiefly of the sheep's fescue meadow oat grass Festuca ovina Avenula pratensis community and contains a number of nationally rare plants. It extends for 1.5 kilometres along a moderate, predominantly west facing, slope of the Upper Chalk to the south of Salisbury. The regular grazing by both cattle and sheep has produced a sward rich in herbs, sedges and grasses. In addition to sheep's fescue and meadow oat grass, quaking grass Briza media and crested hair grass Koeleria macrantha are widespread and upright brome Bromus erectus is abundant in some areas. Glaucous sedge Carex flacca is a constant component of the turf while both spring sedge Carex caryophyllea and the nationally restricted dwarf sedge Carex humilis are less evenly distributed. Herbs constitute a large proportion of the vegetation and many species typical of unimproved chalk soils are plentiful including salad burnet Poterium sanguisorba, dwarf thistle Cirsium acaule, fairy flax Linum catharticum and hoary plantain Plantago media. Several more uncommon species characteristic of high quality chalk grassland are frequent such as horseshoe vetch Hippocrepis comosa, chalk milkwort Polygala calcarea and devil's bit scabious Succisa pratensis. Nationally restricted species include the low growing bastard toadflax Thesium humifusum and the diminutive burnt orchid Neotinea ustulata; the former is locally common on the down while the latter forms a large colony. Several other orchids are well represented including green winged orchid Anacamptis morio, pyramidal orchid Anacamptis pyramidalis and fragrant orchid Gymnadenia conopsea. Several hundred spikes of the late flowering autumn lady's tresses Spiranthes spiralis have been noted in recent years. Anthills are widely scattered over the slopes of the down. Species characteristic of these nest mounds include many with a trailing habit such as common rock rose Helianthemum nummularium, wild thyme Thymus praecox and lady's bedstraw Galium verum occasionally growing with mouse ear hawkweed Hieraciumpilosella. The northern section of the down has a fine patchwork of scrub and grassland habitats, particularly on the lower slopes. hawthorn Crataegus monogyna predominates but a range of other shrubs is present including buckthorn Rhamnus cathartica, holly Ilex aquifolium, blackthorn Prunus spinosa and wayfaring tree Viburnum lantana. Amongst the commoner butterflies recorded are small heath Coenonympha pamphilus and common blue Polymmatus icarus. Also occurring is the rarer small blue Cupido minimus, whose larvae feed on kidney vetch Anthyllis vulneraria.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
small heath Coenonympha pamphilus VU butterfly nymphalidae
small blue Cupido minimus NT butterfly lycaenidae
common blue butterfly Polymmatus icarus Not listed in GB list butterfly lycaebidae
meadow oat grass Avenula pratensis Not listed in GB list grass poaceae
quaking grass Briza media VU grass poaceae
upright brome Bromus erectus Not listed in GB list grass poaceae
sheep's fescue Festuca ovina LC grass poaceae
crested hair-grass Koeleria macrantha NT grass poaceae
green-winged orchid Anacamptis morio NT herb orchidaceae
pyramidal orchid Anacamptis pyramidalis LC herb orchidaceae
lady's fingers (kidney vetch) Anthyllis vulneraria NT herb fabaceae
dwarf thistle Cirsium acaule VU herb asteraceae
lady's bedstraw Galium verum LC herb rubiaceae
fragrant orchid Gymnadenia conopsea NT herb orchidaceae
rock roses Helianthemum nummularium VU herb cistaceae
horseshoe vetch Hippocrepis comosa VU herb fabaceae
fairy flax Linum catharticum LC herb linaceae
burnt orchid Neotinea ustulata EN herb orchidaceae
hoary plantain Plantago media LC herb plantaginaceae
chalk milkwort Polygala calcarea VU herb polygalaceae
salad burnet Poterium sanguisorba VU herb rosaceae
autumn lady's tresses Spiranthes spiralis LC herb orchidaceae
devils-bit scabious Succisa pratensis VU herb caprifoliaceae
bastard toadflax Thesium humifusum VU herb santalaceae
creeping thyme Thymus praecox Not listed in GB list herb lamiaceae
spring-sedge Carex caryophyllea NT sedge cyperaceae
glaucus sedge Carex flacca LC sedge cyperaceae
dwarf sedge Carex humilis LC sedge cyperaceae
hawthorn Crataegus monogyna LC shrub rosaceae
blackthorn Prunus spinosa LC shrub rosaceae
buckthorn Rhamnus cathartica LC shrub rhamnaceae
wayfaring tree Viburnum lantana LC shrub caprifoliaceae
holly Ilex aquifolium LC tree aquifoliaceae

Plant communities

W20 — Montane scrub

Salix lapponum-Luzula sylvatica scrub

Salix arbuscula, Salix cinerea, Salix lapponum, Salix myrsinites, Salix phylicifolia, Salix reticulata, Empetrum nigrum, Calluna vulgaris, Salix lanata, Vaccinium myrtillus, Vaccinium uliginosum, Carex atrata, Carex bigelowii, Carex binervis, Carex flacca, Luzula multiflora, Luzula sylvatica, Huperzia selago, Selaginella selaginoides, Aulacomnium palustre, Mnium hornum, Philonotis fontana, Plagiomnium undulatum, Rhizomnium punctatum, Dicranum bonjeanii, Dicranum majus, Dicranum scoparium, Fissidens adianthoides, Racomitrium lanuginosum, Calliergonell cuspidatum, Ctenidium molluscum, Hylocomium splendens, Hypnum callichroum, Hypnum cupressiforme, Palustriella commutatum, Plagiothecium denticulatum, Plagiothecium undulatum, Pleurozium schreberi, Ptilium crista-castrensis, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sanionia uncinata, Scorpidium revolvens, Thuidium tamariscinum, Atrichum undulatum, Polytrichastrum alpinum, Sphagnum capillifolium, Sphagnum fallax, Sphagnum girgensohnii, Sphagnum palustre, Sphagnum russowii, Sphagnum squarrosum, Sphagnum subnitens, Sphagnum teres, Barbilophozia barbata, Chiloscyphus polyanthos, Diplophyllum albicans, Lophocolea bidentata, Plagiochila porelloides, Ptilidium ciliare, Scapania undulata, Cladonia squamosa, Peltigera canina, Angelica sylvestris, Caltha palustris, Hieraclium spp., Saussurea alpina, Solidago virgaurea, Campanula rotundifolia, Succisa pratensis, Valeriana officinalis, Rhodiola rosea, Vaccinium vitis-idaea, Thymus praecox, Epilobium anagallidifolium, Dactylorhiza viridis, Euphrasia officinalis, Rhinanthus minor, Oxalis acetosella, Oxyria digyna, Polygonum viviparum, Rumex acetosa, Anemone nemorosa, Ranunculus acris, Thalictrum alpinum, Alchemilla alpina, Alchemilla glabra, Filipendula ulmaria, Geum rivale, Galium boreale, Galium saxatile, Saxifraga aizoides, Saxifraga hypnoides, Saxifraga oppositifolia, Saxifraga stellaris, Viola riviniana, Agrostis canina, Agrostis capillaris, Anthoxanthum odoratum, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Nardus stricta, Dryopteris dilatata, Phegopteris connectilis

W21 — Hedgerow scrub, Mixed scrub

Crataegus monogyna-Hedera helix scrub

Hedera helix, Salix cinerea, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Corylus avellana, Fagus sylvatica, Quercus robur, Fraxinus excelsior, Malus sylvestris, Sorbus aria, Taxus baccata, Ulmus glabra, Ulmus procera, Sambucus nigra, Viburnum lantana, Euonymus europaeus, Cornus sanguinea, Juniperus communis, Ligustrum vulgare, Clematis vitalba, Rhamnus cathartica, Crataegus laevigata, Crataegus monogyna, Prunus spinosa, Juncus effusus, Plagiomnium undulatum, Brachythecium rutabulum, Kindbergia praelonga, Rhynchostegium confertum, Tamus communis, Heracleum sphondylium, Torilis japonica, Arum maculatum, Arctium minus, Cirsium arvense, Lonicera periclymenum, Moehringia trinervia, Silene dioica, Stellaria graminea, Stellaria holostea, Stellaria media agg., Calystegia sepium, Mercurialis perennis, Geranium robertianum, Iris foetidissima, Glechoma hederacea, Lamium purpureum, Origanum vulgare, Stachys sylvatica, Teucrium scorodonia, Allium ursinum, Hyacinthoides non-scripta, Circaea lutetiana, Rumex sanguineus, Anemone nemorosa, Ranunculus repens, Fragaria vesca, Geum urbanum, Potentilla sterilis, Poterium sanguisorba, Rosa arvensis, Rosa canina, Rubia peregrina, Rubus fruticosus agg., Galium aparine, Urtica dioica, Viola riviniana, Anisantha sterilis, Arrhenatherum elatius, Brachypodium pinnatum, Brachypodium sylvaticum, Bromopsis erecta, Dactylis glomerata, Elytrigia repens, Holcus lanatus, Holcus mollis, Poa trivialis, Asplenium scolopendrium, Pteridium aquilinum, Dryopteris filix-mas

W22 — Hedgerow scrub, Mixed scrub

Prunus spinosa-Rubus fruticosus scrub

Hedera helix, Acer campestre, Corylus avellana, Ulex europaeus, Prunus spinosa, Plagiomnium undulatum, Brachythecium rutabulum, Eurhynchium striatum, Kindbergia praelonga, Thuidium tamariscinum, Atrichum undulatum, Lophocolea bidentata, Achillea millefolium, Cardamine flexuosa, Lonicera periclymenum, Moehringia trinervia, Silene dioica, Silene uniflora, Stellaria media agg., Mercurialis perennis, Geranium robertianum, Stachys sylvatica, Teucrium scorodonia, Hyacinthoides non-scripta, Oxalis acetosella, Digitalis purpurea, Plantago lanceolata, Veronica chamaedrys, Armeria maritima, Rumex acetosa, Filipendula ulmaria, Geum urbanum, Rosa canina, Rubus fruticosus agg., Rubus idaeus, Galium aparine, Urtica dioica, Viola riviniana, Agrostis capillaris, Brachypodium sylvaticum, Dactylis glomerata, Festuca rubra, Holcus lanatus, Holcus mollis, Poa trivialis, Asplenium scolopendrium, Pteridium aquilinum, Dryopteris borreri, Dryopteris filix-mas