Saltbox Hill

Site of Special Scientific Interest · 51.3306, 0.0191

Also within

Greater London County

Condition (Natural England)

Unfavourable Recovering (3) Favourable (2)
UnitFeatureConditionArea (ha)Assessed
TQ401603 Unfavourable Recovering 7.82 2012-08-23
TQ402605 Unfavourable Recovering 1.71 2012-08-23
TQ403604 Unfavourable Recovering 1.71 2012-08-23
TQ407609 Favourable 6.79 2018-07-31
TQ409604 Favourable 2.93 2018-07-31

Geology & landscape

Rock Type: Chalk

Description

Description Saltbox Hill encompasses a relic complex of chalk grassland and open scrub clearings on the slopes of a downland valley. The grassland contains a diverse flora of typical chalk downland species and is especially rich in plants with a restricted distribution in Greater London. A large variety of butterfly species are present, including some of national importance due to their declining populations in Britain. The site lies on steep sided slopes in a northward running dry valley system on the North Downs. The eastern slope supports a mosaic of unimproved chalk grassland amongst an open scrub of mainly hawthorn Crataegus monogyna. These areas grade into dense scrub and belts of ash Fraxinus excelsior and beech Fagus sylvatica hanger woodland which occupy adjoining banks on the steepest ground. To the west a small tributary valley contains a further expanse of chalk grassland with varying amounts of low hawthorn scrub. In recent years some of this scrub has been cleared and here the grassland is regenerating with a diverse variety of chalk downland plants. Owing to the cessation of livestock grazing, the majority of the grassland is characteristed by a few oarse grass species, especially upright broom Bromus erectus and false brome Brachypodium sylvaticum. Within this sward there are a variety of other grasses typical of chalk soils such as quaking grass Briza media, meadow oat grass Avenula pratensis and downy oat grass Avenula pubescens. The grassland is however, particularly of interest for the rich diversity and abundance of colourful flowering herbs. Many are characteristic of unimproved chalk grassland but now have a very restricted distribution in Greater London due to a continuing reduction in the extent of such grassland areas. The more noteworthy of these species include, yellow wort Blackstonia perfoliata, carline thistle Carlina vulgaris, dwarf thistle Cirsium acaule, wild basil Clinopodium vulgare, horseshoe vetch Hippocrepis comosa, marjoram Origanum vulgare and cowslip Primula veris. In addition the site is one of the last remaining examples of old grassland containing yellow rattle Rhinanthus minor in the county. A further speciality of the site is the rich diversity of orchids. In total ten species are present including pyramidal orchid Anacamptis pyramidalis, white helleborine Cephalanthera damasonium, bee orchid Ophrys apifera and fly orchid Ophrys insectifera. Part of the eastern slope supports a notable abundance of man orchid Orchis anthorpophora a nationally uncommon plant which is mainly confined to the chalk downlands of southern England. The scrub is characterised by an abundance of hawthorn which in places occurs in predominantly single species stands. Elsewhere associated shrubs include, dogwood Cornus sanguinea, buckthorn Rhamnus cathartica and wayfaring tree Viburnum lantana. The combination of habitats, from high woodland to sheltered grassland slopes rich in nectar yielding plants, supports a large and diverse range of butterflies. Over 30 species have been recorded, many on a regular basis. These include four species which are of national importance owing to their decline in numbers throughout Britain, the chalk hill blue Polyommatus coridon, dark green fritillary Argynnis aglaja, dingy skipper Erynnis tages and grizzled skipper Pyrgus malvae. Among the other commoner butterfly species are the small copper Lycaena phlaeas and common blue Polyommatus icarus.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
dark green fritillary Argynnis aglaja Not listed in GB list butterfly nymphalidae
dingy skipper Erynnis tages LC butterfly hesperiidae
small copper Lycaena phlaeas LC butterfly lycaenidae
chalkhill blue Polyommatus coridon VU butterfly lycaenidae
common blue Polyommatus icarus LC butterfly lycaenidae
grizzled skipper Pyrgus malvae VU butterfly hesperiidae
meadow oat grass Avenula pratensis Not listed in GB list grass poaceae
downy oat grass Avenula pubescens LC grass poaceae
wood false brome Brachypodium sylvaticum LC grass poaceae
quaking grass Briza media VU grass poaceae
upright brome Bromus erectus Not listed in GB list grass poaceae
pyramidal orchid Anacamptis pyramidalis LC herb orchidaceae
yellowwort Blackstonia perfoliata LC herb gentianaceae
carline thistle Carlina vulgaris LC herb asteraceae
white helleborine Cephalanthera damasonium LC herb orchidaceae
dwarf thistle Cirsium acaule VU herb asteraceae
wild basil Clinopodium vulgare LC herb lamiaceae
horseshoe vetch Hippocrepis comosa VU herb fabaceae
bee orchid Ophrys apifera LC herb orchidaceae
fly orchid Ophrys insectifera VU herb orchidaceae
man orchid Orchis anthorpophora Not listed in GB list herb orchidaceae
wild marjoram Origanum vulgare LC herb lamiaceae
cowslip Primula veris LC herb primulaceae
yellow-rattle Rhinanthus minor DD herb orobanchaceae
dogwood Cornus sanguinea LC shrub cornaceae
hawthorn Crataegus monogyna LC shrub rosaceae
buckthorn Rhamnus cathartica LC shrub rhamnaceae
wayfaring tree Viburnum lantana LC shrub caprifoliaceae
beech Fagus sylvatica LC tree fabiaceae
ash Fraxinus excelsior LC tree oleaceae

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