Homington and Coombe Bissett Downs

Site of Special Scientific Interest · 51.0200, -1.8522

Condition (Natural England)

Unfavourable Declining (1) Favourable (4) Unfavourable Recovering (2)
UnitFeatureConditionArea (ha)Assessed
SU103242 Unfavourable Declining 0.66 2009-06-09
SU104245 Favourable 7.55 2009-09-02
SU110246 Favourable 8.43 2010-09-16
SU110250 Favourable 8.43 2010-09-16
SU110254 Favourable 8.43 2010-09-16
SU119252 Unfavourable Recovering 8.47 2009-09-01
SU121246 Unfavourable Recovering 8.47 2009-09-01

Geology & landscape

Rock Type: Chalk

Birds & fish recorded

Birds

SpeciesSeason
willow warbler Unknown

Description

Description Homington and Coombe Bissett Downs SSSI encompasses several blocks of botanically rich chalk grassland, a habitat which has suffered substantial decline nationally, due to agricultural intensification. Several animal and plant species of a restricted distribution in Britain are well established on parts of the downs. The site occupies a series of adjacent dry valleys situated on the Upper Chalk south west of Salisbury. There are gentle and steep slopes and lynchet banks which are mostly west facing. The grassland has a varied structure with both regularly grazed turf, characterised by the grasses sheep's fescue Festuca ovina and meadow oat grass Avenula pratensis and longer sward dominated by upright brome Bromus erectus. Several other grasses are widespread throughout including quaking grass Briza media, crested hair grass Koeleria macrantha and downy oat grass Avenula pubescens. Glaucous and spring sedge Carex flacca and Carex caryophyllea are also common. The nationally restricted dwarf sedge Carex humilis, which is highly characteristic of the south west Wiltshire chalk, is scattered over this site, becoming a major component where the turf is closely grazed. A wide range of herbs typically associated with agriculturally unimproved chalk grassland are found such as salad burnet Poterium sanguisorba, burnet saxifrage Pimpinella saxifraga, dwarf thistle Cirsium acaule, fairy flax Linum catharticum and autumn gentian Gentianella amarella. In areas of taller sward field scabious Knautia arvensis, common knapweed Centaurea nigra and greater knapweed C. scabiosa are frequent. There are, a number of plant species especially indicative of management without ploughing, fertilisers or herbicides such as dropwort Filipendula vulgaris, saw wort Serratula tinctoria, devil's bit scabious Succisa pratensis, dyer's greenweed Genista tinctoria and autumn lady's tresses Spiranthes spiralis. In addition there is a thriving population of bastard toadflax Thesium humifusum, a species of a very limited distribution in Britain. Mixed scrub dominated by hawthorn is a feature of the downs occurring both sparsely and in dense patches. Blackthorn and elder are also constituents, together with three species that are less commonly found on downland sites, buckthorn, holly and gorse. Favourable conditions for a variety of butterflies are provided by the mixture of open grassland and scrub. Typical species are meadow brown, common blue, marbled white and brimstone. The chalk hill blue and nationally restricted Adonis blue are found where their larval food plant, horseshoe vetch Hippocrepis comosa grows in the well grazed turf. Ant hills produced by the yellow meadow ant Lasius flavus are occasional. The scrub is also valuable to birds although a full survey has not yet been undertaken. Species include yellowhammer, willow warbler, goldfinch and skylark.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
yellow meadow ant Lasius flavus Not listed in GB list ant formicinae
yellowhammer Emberiza citrinella LC (Breeding) bird-bunting emberizidae
goldfinch Carduelis carduelis LC (Breeding) bird-finch fringillidae
skylark Alauda arvensis VU (Breeding) bird-lark alaudidae
willow warbler Phylloscopus trochilus LC (Breeding) bird-warbler phylloscopidae
meadow oat grass Avenula pratensis Not listed in GB list grass poaceae
downy oat grass Avenula pubescens LC 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
black knapweed Centaurea nigra LC herb asteraceae
dwarf thistle Cirsium acaule VU herb asteraceae
dropwort Filipendula vulgaris LC herb rosaceae
dyer's greenweed Genista tinctoria LC herb fabaceae
autumn gentian Gentianella amarella LC herb gentianaceae
horseshoe vetch Hippocrepis comosa VU herb fabaceae
field scabious Knautia arvensis LC herb caprifoliaceae
fairy flax Linum catharticum LC herb linaceae
burnet saxifrage Pimpinella saxifraga NT herb apiaceae
salad burnet Poterium sanguisorba VU herb rosaceae
saw wort Serratula tinctoria VU herb asteraceae
autumn lady's tresses Spiranthes spiralis LC herb orchidaceae
devils-bit scabious Succisa pratensis VU herb caprifoliaceae
bastard toadflax Thesium humifusum VU herb santalaceae
spring-sedge Carex caryophyllea NT sedge cyperaceae
glaucus sedge Carex flacca LC sedge cyperaceae
dwarf sedge Carex humilis LC sedge cyperaceae

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