Riddlesdown
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Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| TQ325603 | — | Unfavourable Recovering | 19.71 | 2010-04-27 |
| TQ332598 | — | Unfavourable Recovering | 19.71 | 2010-04-27 |
| TQ332599 | — | Favourable | 12.88 | 2010-04-27 |
| TQ336593 | — | Unfavourable Recovering | 19.71 | 2010-04-27 |
| TQ337594 | — | Favourable | 2.05 | 2021-03-11 |
Habitats
Geology & landscape
Mining / Industrial: Quarry · Rock Type: Chalk
Description
Area, 32.0 ha. 79.1 ac. Description Riddlesdown Common covers an extensive section of a south west facing scarp slope towards the northern end of the North Downs. The site is of particular interest as the largest single expanse of long established calcareous scrub in Greater London and also for its herb rich chalk grassland. The variety of shrub and tree species within the scrub is unusually diverse for the county and includes a particularly high abundance of mature yew Taxus baccata. The site also contains part of an adjoining derelict chalk quarry and between them these downland habitats support four nationally scarce species of chalk plant. The steep scarp slope cuts into the Middle and Upper Chalk and was traditionally managed as sheep pasture until the early part of this century. The cessation of sheep grazing has allowed the progressive invasion of scrub until it now covers a large part of the mid to lower slopes. In general the scrub community is of considerable age and comprises over twenty shrub and tree species. These include nearly all the species characteristic of dry chalk soils in Southern England and from an uncommonly diverse assemblage for Greater London. Yew is particularly abundant and is found scattered throughout the scrub and also in numerous distinct groves. hazel Corylus avellana, ash Fraxinus excelsior, and common whitebeam Sorbus aria are also frequent components, with other typical calcareous scrub species including spindle Euonymus europaeus, buckthorn Rhamnus cathartica, dogwood Cornus sanguinea and wayfaring tree Viburnum lantana. This is also one of the few remaining localities in Greater London for juniper Juniperus communis, which is present as a small number of scattered individuals. Dense canopy shade precludes a diverse ground flora. The ground flora is dominated by ivy Hedera helix with small patches of dog’s mercury Mercurialis perennis and sanicle Sanicula europaea, but is notable for two colonies of green flowered helleborine Epipactis phyllanthes. This is a nationally scarce plant and is known from only a few localities in Greater London. Herb rich chalk grasslands occur on the upper slopes of the down where scrub invasion has been checked by mowing and also in a few clearings which have been maintained by rabbit grazing. The predominant grass is upright brome Bromus erectus with frequent red fescue Festuca rubra and quaking grass Briza media. Amongst the rich herb components are squinancywort Asperula cynanchica, yellow wort Blackstonia perfoliata, glaucous sedge Carex flacca, dropwort Filipendula vulgaris, autumn gentian Gentianella amarella and yellow rattle Rhinanthus minor. Many of the herb species are now uncommon in Greater London owing to a general and considerable decline in their habitat. Two nationally scarce species are also found, early gentian Gentianella anglica and round headed rampion Phyteuma orbiculare. The rim of the adjoining chalk quarry supports a legume rich grassland on calcareous clay which provides an interesting contrast to the grasslands on the down. The sward includes kidney vetch Anthyllis vulneraria, grass vetchling Lathyrus nissolia, hairy tare Vicia hirsuta and common vetch Vicia sativa. Of particular interest are the chalk spoil heaps which support a sizeable colony of white mullein Verbascum lychnitis, a further nationally scarce plant species. Of additional interest is the assemblage of invertebrate species supported by the wide diversity of herbs in the open habitats of the site. These include the nationally scarce Roesel’s bush cricket Metrioptera roeselii, eight nationally scarce species of beetle and 19 species of butterfly.
Species mentioned
Show the 30 species mentioned in the description, with red-list statusPlant communities
W21 — Hedgerow scrub, Mixed scrub
Crataegus monogyna-Hedera helix scrub
Matches 11 species from the description above: Cornus sanguinea, Corylus avellana, Euonymus europaeus, Fraxinus excelsior, Hedera helix, Juniperus communis, Mercurialis perennis, Rhamnus cathartica, Sorbus aria, Taxus baccata, Viburnum lantana
Show 81 indicator speciesHedera 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
Matches 4 species from the description above: Corylus avellana, Festuca rubra, Hedera helix, Mercurialis perennis
Show 49 indicator speciesHedera 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
W20 — Montane scrub
Salix lapponum-Luzula sylvatica scrub
Matches 3 species from the description above: Carex flacca, Festuca rubra, Rhinanthus minor
Show 107 indicator speciesSalix 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
Insects to look out for
These moths and butterflies are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a hostplant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.
| Species | Status | Via hostplant |
|---|---|---|
| The lappet Gastropacha quercifolia |
Endangered | Rhamnus cathartica |
| Scarce vapourer Orgyia recens |
Endangered | Corylus avellana |
| Least minor Photedes captiuncula |
Endangered | Carex flacca |
| The sprawler Asteroscopus sphinx |
Vulnerable | Corylus avellana, Fraxinus excelsior, Viburnum lantana |
| Mottled umber Erannis defoliaria |
Vulnerable | Corylus avellana |
| Juniper pug Eupithecia pusillata |
Vulnerable | Juniperus communis, Juniperus spp. |
| Satyr pug Eupithecia satyrata |
Vulnerable | Rhinanthus minor, Verbascum spp. |
| The lackey Malacosoma neustria |
Vulnerable | Corylus avellana |
| Pale brindled Phigalia pilosaria |
Vulnerable | Cornus sanguinea, Corylus avellana, Fraxinus excelsior, Rhamnus cathartica |
| Pale eggar Trichiura crataegi |
Vulnerable | Corylus avellana |
| Large thorn Ennomos autumnaria |
Near Threatened | Corylus avellana |
| Dusky thorn Ennomos fuscantaria |
Near Threatened | Fraxinus excelsior |
| Autumnal rustic Eugnorisma glareosa |
Near Threatened | Vicia sativa |
| Rosy minor Litoligia literosa |
Near Threatened | Carex flacca |
Hostplant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation (Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.