Pitstone Hill

Site of Special Scientific Interest · 51.8213, -0.6213

Condition (Natural England)

Favourable (1)
UnitFeatureConditionArea (ha)Assessed
SP951145 Favourable 22.38 2019-10-04

Geology & landscape

Rock Type: Chalk

Birds & fish recorded

Birds

SpeciesSeason
willow warbler Breeding

Description

Area, 22.91 hectares 56.61 ac Description An area of chalk downland on a steeply sloping, west facing section of the Chiltern escarpment. The grassland on the steeper parts of the slope is very rich botanically and supports several locally and nationally uncommon plants. Small areas of improved pasture, mixed woodland and scrub are also present. The site is situated on Middle Chalk with very thin, poor soil on the steep slopes, but thicker, slightly richer soil on the top of the plateau. The botanically rich grassland is mainly associated with the steeper, lower parts of the site and on the sides of the ditches and trackways of the archaeological features. The range of plants present includes the nationally scarce pasque flower Pulsatilla vulgaris and field fleawort Tephroseris integrifolia as well as more common species such as clustered bellflower Campanula glomerata, frog orchid Dactylorhiza viridis, large thyme Thymus pulegioides, autumn gentian Gentianella amarella, dwarf thistle Cirsium acaule and squinancywort Asperula cynanchica. The grassland is taller amongst the areas of scattered scrub with upright brome Bromopsis erecta, common spotted orchid Dactylorhiza fuchsii, yellow rattle Rhinanthus minor, wild basil Clinopodium vulgare and cowslip Primula veris. Mounds of the yellow meadow ant Lasius flavus are abundant in parts of the grassland. The improved grassland on the upper part of the site is dominated by grasses, but retains occasional chalk grassland plants such as burnet saxifrage Pimpinella saxifraga, glaucous sedge Carex flacca and hoary plantain Plantago media. The open ground is important in supporting a large number of breeding meadow pipits and skylarks, while the areas of scrub and woodland support breeding willow warbler, yellowhammer and dunnock. Twenty six butterfly species have been recorded including the small blue Cupido minimus, Duke of Burgundy Hamearis lucina and silver spotted and Essex skippers Hesperia comma and Thymelicus lineola.

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
dunnock Prunella modularis LC (Breeding) bird-accentor prunellidae
yellowhammer Emberiza citrinella LC (Breeding) bird-bunting emberizidae
willow warbler Phylloscopus trochilus LC (Breeding) bird-warbler phylloscopidae
small blue Cupido minimus NT butterfly lycaenidae
Duke of Burgundy Hamearis lucina VU butterfly riodinidae
silver-spotted skipper Hesperia comma VU butterfly hesperiidae
Essex skipper Thymelicus lineola LC butterfly hesperiidae
upright brome Bromopsis erecta LC grass poaceae
squinancywort Asperula cynanchica VU herb rubiaceae
clustered bellflower Campanula glomerata VU herb campanulaceae
dwarf thistle Cirsium acaule VU herb asteraceae
wild basil Clinopodium vulgare LC herb lamiaceae
spotted orchids Dactylorhiza fuchsii LC herb orchidaceae
frog orchid Dactylorhiza viridis VU herb orchidaceae
autumn gentian Gentianella amarella LC herb gentianaceae
burnet saxifrage Pimpinella saxifraga NT herb apiaceae
hoary plantain Plantago media LC herb plantaginaceae
cowslip Primula veris LC herb primulaceae
pasque flower Pulsatilla vulgaris EN herb ranunculaceae
yellow-rattle Rhinanthus minor DD herb orobanchaceae
field fleawort Tephroseris integrifolia VU herb asteraceae
large garden Thymus pulegioides VU herb lamiaceae
glaucus sedge Carex flacca 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