Knapp and Barnett's Downs

Site of Special Scientific Interest · 51.0460, -1.9732

Condition (Natural England)

Favourable (9) Unfavourable Recovering (3)
UnitFeatureConditionArea (ha)Assessed
SU017271 Favourable 11.5 2011-08-01
SU017275 Unfavourable Recovering 0.61 2009-04-08
SU019275 Unfavourable Recovering 18.32 2010-06-29
SU021271 Favourable 11.5 2011-08-01
SU024267 Favourable 3.53 2010-06-29
SU024272 Favourable 3.53 2010-06-29
SU026274 Favourable 6.11 2011-08-01
SU028267 Favourable 6.2 2011-08-01
SU031267 Favourable 3.67 2011-08-01
SU032266 Favourable 3.67 2011-08-01
SU033263 Unfavourable Recovering 3.83 2010-08-26
SU033271 Favourable 12.95 2010-08-20

Geology & landscape

Rock Type: Chalk

Description

Description Knapp and Barnett's Downs form a large area of botanically rich chalk grassland, south west of Salisbury. The site supports a grassland community which is rare in Britain and which includes uncommon plants and invertebrates. The area of chalk grassland in Britain has declined considerably this century, largely following agricultural improvement by re seeding and the use of fertilisers and herbicides. Wiltshire has approximately 70 percent of the semi natural grassland remaining. The site occupies a complex of dry valleys on Middle Chalk and has a wide range of aspects. The grassland community conforms to a type which is virtually confined to areas of the Wiltshire and Dorset Chalk. Sheep's fescue Festuca ovina and meadow oat grass Avenula pratensis are the dominant grasses in a sward also composed of crested hair grass Koeleria macrantha, yellow oat grass Trisetum flavescens, quaking grass Briza media and glaucous sedge Carex flacca. The rare dwarf sedge Carex humilis, a plant with a British distribution centred on south Wiltshire and north Dorset, is abundant in some areas. Prominent herbs on the downs include harebell Campanula rotundifolia, clustered bellflower C. glomerata, dropwort Filipendula vulgaris and pyramidal orchid Anacamptis pyramidalis, whilst uncommon species include chalk milkwort Polygala calcarea and bastard toadflax Thesium humifusum, both of which are largely confined to the southern chalk. Herbs which elsewhere are typical of the dwarf sedge grasslands of Wiltshire, including saw wort Serratula tinctoria and betony Betonica officinalis, are unusually scarce. Areas with less intensive grazing are dominated by coarse grasses together with common rock rose Helianthemum nummularium, yellow rattle Rhinanthus minor and greater and common knapweed Centaurea scabiosa and C. nigra, all of which are less common on the remainder of the site. hawthorn is common as both dense blocks and scattered bushes. Other scrub species include dog rose, gorse, common buckthorn, holly and yew. The scrub supports populations of song birds, including goldcrest and yellowhammer. Nationally uncommon invertebrate species occurring on the site include the plant bug Canthophorus impressus which feeds on bastard toadflax and the Adonis blue butterfly which has undergone a considerable contraction in its distribution this century. Other butterflies on the down include chalkhill blue and dingy skipper.

Species mentioned

English name
search for this in other sites
Latin name
search with Google
IUCN / Red List Type Family
yellowhammer Emberiza citrinella LC (Breeding) bird-bunting emberizidae
goldcrest Regulus regulus LC (Breeding) bird-crest regulidae
bastard toadflax bug Canthophorus impressus LC bug cydnidae
meadow oat grass Avenula pratensis Not listed in GB list grass poaceae
quaking grass Briza media VU grass poaceae
sheep's fescue Festuca ovina LC grass poaceae
crested hair-grass Koeleria macrantha NT grass poaceae
yellow oat grass Trisetum flavescens LC grass poaceae
pyramidal orchid Anacamptis pyramidalis LC herb orchidaceae
betony Betonica officinalis VU herb lamiaceae
harebell Campanula rotundifolia LC herb campanulaceae
greater knapweed Centaurea scabiosa LC herb asteraceae
dropwort Filipendula vulgaris LC herb rosaceae
rock roses Helianthemum nummularium VU herb cistaceae
chalk milkwort Polygala calcarea VU herb polygalaceae
yellow-rattle Rhinanthus minor DD herb orobanchaceae
saw wort Serratula tinctoria VU herb asteraceae
bastard toadflax Thesium humifusum VU herb santalaceae
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