St. Dunstan's Well Catchment

Site of Special Scientific Interest · 51.2261, -2.4930

Also within

Somerset County

Condition (Natural England)

Favourable (6) Unfavourable Declining (1)
UnitFeatureConditionArea (ha)Assessed
ST655472 Favourable 0.28 2010-11-12
ST656472 Favourable 2.06 2010-11-12
ST656475 Favourable 17.41 2020-02-25
ST658478 Favourable 0.23 2010-12-02
ST667475 Favourable 5.96 2010-11-12
ST668473 Unfavourable Declining 7.31 2010-11-11
ST669476 Favourable 1.79 2010-12-02

Geology & landscape

Geological Feature: Cave / Cavern · Mining / Industrial: Quarry · Geological Period: Quaternary

Landscape processes: Karst

Description

Area, 39.8 ha. 98.3 ac. Description a Geological, St Dunstan's Well Catchment is an important and well known cave system which includes a series of spectacularly decorated caves which in total extend to about four miles of mapped passage. The caves were formed mainly by the erosive action of water flowing beneath the water table at considerable pressure so called 'phreatic' development, but as the water table has fallen many of the caves now lie well above it and the system now contains a variety of cave formations stalagmites, stalactites and calcite curtains which in their extent and preservation are unsurpassed in Britain. Shatter Cave and Withyhill Cave are generally considered to be the finest decorated caves in Britain in terms of their sheer abundance of pure white and translucent calcite deposits. These caves and the sediments which occur in and are associated with them, record a long and detailed geological history which extends back through much of the Pleistocene Ice Age and this makes them of great importance to geologists studying the geological evolution of southern England. b Biological, An area of nationally rare species rich unimproved calcareous grassland of the sheep's fescue meadow oat grass type occurs in the field to the east of Stoke Lane Quarry. sheep's fescue Festuca ovina, meadow oat grass Avenula pratensis, crested dog's tail Cynosurus cristatus and common bent Agrostis capillaris are the most common grasses. crested hair grass Koeleria macrantha, downy oat grass Avenula pubescens, yellow oat grass Trisetum flavescens and heath grass Danthonia decumbens also occur. Glaucous sedge Carex flacca and spring sedge Carex caryophyllea are abundant. Herbs of interest include lady's mantle Alchemilla filicaulis, devil's bit scabious Succisa pratensis, salad burnet Poterium sanguisorba, cowslip Primula veris, fairy flax Linum catharticum, common rose Helianthemum nummularium and wild thyme Thymus praecox. early purple orchid Orchis mascula and common spotted orchid Dactylorhiza fuchsii are widespread. Small numbers of greater horseshoe bat Rhinolophus ferrumequinum, lesser horseshoe bat Rhinolophus hipposideros and natterer's bat Myotis nattereri hibernate in the cave system.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
Natterer's bat Myotis nattereri LC bat vespertillonidae
greater horseshoe bat Rhinolophus ferrumequinum LC bat vespertillonidae
lesser horseshoe bat Rhinolophus hipposideros LC bat vespertillonidae
common bent Agrostis capillaris LC grass poaceae
meadow oat grass Avenula pratensis Not listed in GB list grass poaceae
downy oat grass Avenula pubescens LC grass poaceae
crested dog's tail Cynosurus cristatus LC grass poaceae
heath grass Danthonia decumbens NT 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
lady's mantle Alchemilla filicaulis VU herb rosaceae
spotted orchids Dactylorhiza fuchsii LC herb orchidaceae
rock roses Helianthemum nummularium VU herb cistaceae
fairy flax Linum catharticum LC herb linaceae
early purple orchid Orchis mascula LC herb orchidaceae
salad burnet Poterium sanguisorba VU herb rosaceae
cowslip Primula veris LC herb primulaceae
devils-bit scabious Succisa pratensis VU herb caprifoliaceae
creeping thyme Thymus praecox Not listed in GB list herb lamiaceae
spring-sedge Carex caryophyllea NT sedge cyperaceae
glaucus sedge Carex flacca LC sedge cyperaceae

Plant communities

CG9 — Limestone pavement, Lowland calcareous grassland, Upland calcareous grassland

Sesleria albicans-Galium sterneri grassland

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Carex capillaris, Carex caryophyllea, Carex eragrostis, Carex flacca, Carex hostiana, Carex panicea, Carex pulicaris, Kobresia simpliciuscula, Selaginella selaginoides, Rhodobryum roseum, Dicranum scoparium, Ditrichum flexicaule, Fissidens dubius, Encalypta streptocarpa, Racomitrium canescens sens.lat., Racomitrium lanuginosum, Ctenidium molluscum, Homalothecium lutescens, Hylocomium splendens, Hypnum cupressiforme, Neckera crispa, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Rhytidium rugosum, Thuidium tamariscinum, Polytrichum juniperinum, Tortella tortuosa, Barbilophozia barbata, Blepharostoma trichophyllum, Frullania tamarisci, Lophocolea bidentata, Plagiochila asplenioides, Scapania aspera, Tritomaria quinquedentata, Cetraria islandica, Cladonia pocillum, Cladonia rangiformis, Cornicularia aculeata, Pimpinella saxifraga, Achillea millefolium, Antennaria dioica, Bellis perennis, Carlina vulgaris, Cirsium vulgare, Leontodon hispidus, Pilosella officinarum, Taraxacum officianalis, Myosotis alpestris, Cochlearia alpina, Draba incana, Campanula rotundifolia, Scabiosa columbaria, Succisa pratensis, Cerastium fontanum, Minuartia verna, Parnassia palustris, Helianthemum oelandicum icanum, Sedum acre, Anthyllis vulneraria, Hippocrepis comosa, Lotus corniculatus, Trifolium repens, Gentiana verna, Gentianella amarella, Hypericum pulchrum, Thymus praecox, Pinguicula vulgaris, Linum catharticum, Epipactis atrorubens, Euphrasia confusa, Euphrasia officinalis, Plantago lanceolata, Plantago maritima, Veronica officinalis, Polygala vulgaris, Polygonum viviparum, Primula farinosa, Primula vulgaris, Thalictrum minus, Dryas octopetala, Potentilla erecta, Potentilla tabernaemontani, Poterium sanguisorba, Asperula cynanchica, Galium sterneri, Galium verum, Saxifraga hypnoides, Viola hirta, Viola riviniana, Viola rupestris, Agrostis capillaris, Anthoxanthum odoratum, Avenula pratensis, Brachypodium sylvaticum, Briza media, Cynosurus cristatus, Dactylis glomerata, Danthonia decumbens, Deschampsia cespitosa, Festuca ovina, Festuca rubra, Koeleria macrantha, Molinia caerulea, Sesleria caerulea

CG10 — Brownfield, Limestone pavement, Upland calcareous grassland

Festuca ovina-Agrostis capillaris-Thymus praecox grassland

Empetrum nigrum, Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica cinerea, Vaccinium myrtillus, Carex binervis, Carex caryophyllea, Carex demissa, Carex flacca, Carex nigra, Carex panicea, Carex pilulifera, Carex pulicaris, Juncus squarrosus, Luzula campestris, Luzula multiflora, Luzula sylvatica, Selaginella selaginoides, Breutelia chrysocoma, Bryum pallens, Bryum pseudotriquetrum, Mnium hornum, Plagiomnium undulatum, Rhizomnium punctatum, Dicranum scoparium, Ditrichum flexicaule, Fissidens adianthoides, Fissidens osmundoides, Racomitrium canescens sens.lat., Racomitrium lanuginosum, Calliergonell cuspidatum, Ctenidium molluscum, Hylocomium splendens, Hypnum cupressiforme, Hypnum jutlandicum, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sanionia uncinata, Thuidium delicatulum, Thuidium tamariscinum, Tortella tortuosa, Frullania tamarisci, Lophocolea bidentata, Plagiochila asplenioides, Ptilidium ciliare, Scapania undulata, Cetraria islandica, Peltigera canina, Angelica sylvestris, Achillea millefolium, Antennaria dioica, Bellis perennis, Cirsium palustre, Hieraclium spp., Hypochaeris radicata, Jacobaea vulgaris, Pilosella officinarum, Scorzoneroides autumnalis, Solidago virgaurea, Cardamine pratensis, Campanula rotundifolia, Succisa pratensis, Cerastium fontanum, Silene acaulis, Vaccinium vitis-idaea, Lathyrus montanus, Lotus corniculatus, Trifolium repens, Gentianella campestris, Hypericum pulchrum, Thymus praecox, Pinguicula vulgaris, Linum catharticum, Euphrasia confusa, Euphrasia officinalis, Euphrasia scottica, Oxalis acetosella, Plantago lanceolata, Plantago maritima, Veronica officinalis, Polygala serpyllifolia, Polygonum viviparum, Rumex acetosa, Primula vulgaris, Ranunculus acris, Ranunculus repens, Thalictrum alpinum, Alchemilla alpina, Alchemilla filicaulis, Alchemilla glabra, Alchemilla wichurae, Alchemilla xanthochlora, Filipendula ulmaria, Geum rivale, Potentilla crantzii, Potentilla erecta, Potentilla sterilis, Rubus idaeus, Galium boreale, Galium saxatile, Galium sterneri, Galium verum, Saxifraga aizoides, Saxifraga oppositifolia, Viola riviniana, Agrostis canina, Agrostis capillaris, Aira praecox, Anthoxanthum odoratum, Avenula pratensis, Briza media, Cynosurus cristatus, Danthonia decumbens, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Holcus lanatus, Koeleria macrantha, Molinia caerulea, Nardus stricta, Poa pratensis, Blechnum spicant, Pteridium aquilinum, Botrychium lunaria, Thelypteris limbosperma

CG11 — Upland calcareous grassland

Festuca ovina-Agrostis capillaris-Alchemilla alpina grass-heath

Empetrum nigrum, Calluna vulgaris, Erica tetralix, Vaccinium myrtillus, Salix herbacea, Carex bigelowii, Carex binervis, Carex caryophyllea, Carex flacca, Carex panicea, Carex pilulifera, Carex pulicaris, Trichophorum cespitosum, Juncus squarrosus, Juncus trifidus, Luzula campestris, Luzula multiflora, Luzula spicata, Luzula sylvatica, Diphasiastrum alpinum, Huperzia selago, Selaginella selaginoides, Breutelia chrysocoma, Mnium hornum, Plagiomnium undulatum, Dicranum scoparium, Racomitrium canescens sens.lat., Racomitrium lanuginosum, Ctenidium molluscum, Hylocomium splendens, Hypnum cupressiforme, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sanionia uncinata, Thuidium delicatulum, Thuidium tamariscinum, Pogonatum urnigerum, Polytrichastrum alpinum, Barbilophozia lycopodioides, Diplophyllum albicans, Frullania tamarisci, Nardia scalaris, Ptilidium ciliare, Tritomaria quinquedentata, Cetraria islandica, Cladonia pyxidata, Cladonia uncialis, Peltigera canina, Achillea millefolium, Antennaria dioica, Gnaphalium supinum, Hieraclium spp., Scorzoneroides autumnalis, Taraxacum officianalis, Campanula rotundifolia, Succisa pratensis, Cerastium alpinum, Cerastium fontanum, Minuartia sedoides, Silene acaulis, Vaccinium vitis-idaea, Lathyrus montanus, Trifolium repens, Thymus praecox, Pinguicula vulgaris, Linum catharticum, Narthecium ossifragum, Dactylorhiza viridis, Euphrasia officinalis, Oxalis acetosella, Plantago lanceolata, Plantago maritima, Veronica officinalis, Veronica serpyllifolia, Armeria maritima, Polygonum viviparum, Rumex acetosa, Primula vulgaris, Anemone nemorosa, Ranunculus acris, Thalictrum alpinum, Trollius europaeus, Alchemilla alpina, Alchemilla filicaulis, Alchemilla xanthochlora, Filipendula ulmaria, Geum rivale, Potentilla crantzii, Potentilla erecta, Sibbaldia procumbens, Galium boreale, Galium saxatile, Saxifraga aizoides, Saxifraga hypnoides, Saxifraga oppositifolia, Viola canina, Viola palustris, Viola riviniana, Agrostis canina, Agrostis capillaris, Anthoxanthum odoratum, Danthonia decumbens, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Festuca vivipara, Molinia caerulea, Nardus stricta, Blechnum spicant, Botrychium lunaria, Thelypteris limbosperma

CG13 — Limestone pavement, Upland calcareous grassland

Dryas octopetala-Carex flacca heath

Salix repens, Empetrum nigrum, Empetrum nigrum subsp.nigrum, Calluna vulgaris, Juniperus communis, Arctostaphylos uva-ursi, Rubus saxatilis, Carex flacca, Carex panicea, Carex pulicaris, Carex rupestris, Schoenus nigricans, Luzula campestris, Selaginella selaginoides, Breutelia chrysocoma, Dicranum scoparium, Ditrichum flexicaule, Fissidens dubius, Racomitrium lanuginosum, Ctenidium molluscum, Entodon concinnus, Homalothecium lutescens, Hylocomium splendens, Hypnum cupressiforme, Loeskeobryum brevirostre, Neckera complanata, Neckera crispa, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Rhytidium rugosum, Thuidium delicatulum, Thuidium tamariscinum, Tortella tortuosa, Frullania tamarisci, Plagiochila asplenioides, Scapania undulata, Cladonia rangiformis, Solorina saccata, Daucus carota, Antennaria dioica, Bellis perennis, Centaurea nigra, Hypochaeris radicata, Jacobaea vulgaris, Pilosella officinarum, Scorzoneroides autumnalis, Solidago virgaurea, Taraxacum officianalis, Campanula rotundifolia, Succisa pratensis, Cerastium fontanum, Anthyllis vulneraria, Lathyrus montanus, Lotus corniculatus, Trifolium pratense, Trifolium repens, Gentianella amarella, Hypericum pulchrum, Thymus praecox, Pinguicula vulgaris, Linum catharticum, Epipactis atrorubens, Neottia ovata, Orchis mascula, Euphrasia confusa, Euphrasia officinalis, Plantago lanceolata, Plantago maritima, Plantago media, Polygala serpyllifolia, Polygonum viviparum, Primula vulgaris, Ranunculus acris, Thalictrum alpinum, Dryas octopetala, Filipendula ulmaria, Potentilla erecta, Galium saxatile, Galium verum, Saxifraga aizoides, Viola riviniana, Agrostis canina, Agrostis capillaris, Anthoxanthum odoratum, Avenula pratensis, Cynosurus cristatus, Danthonia decumbens, Festuca ovina, Festuca rubra, Festuca vivipara, Koeleria macrantha, Molinia caerulea, Polystichum aculeatum

U4 — Lowland dry acid grassland, Upland acid grassland, Upland calcareous grassland

Festuca ovina-Agrostis capillaris-Galium saxatile grassland

Calluna vulgaris, Vaccinium myrtillus, Carex binervis, Carex caryophyllea, Carex echinata, Carex nigra, Carex panicea, Carex pilulifera, Juncus effusus, Juncus squarrosus, Luzula campestris, Luzula multiflora, Luzula sylvatica, Mnium hornum, Dicranum scoparium, Racomitrium lanuginosum, Hylocomium splendens, Hypnum cupressiforme, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Thuidium tamariscinum, Polytrichastrum alpinum, Polytrichum commune, Lophocolea bidentata, Conopodium majus, Achillea millefolium, Bellis perennis, Cirsium arvense, Cirsium vulgare, Taraxacum officianalis, Campanula rotundifolia, Succisa pratensis, Cerastium fontanum, Lathyrus montanus, Lotus corniculatus, Trifolium pratense, Trifolium repens, Thymus praecox, Euphrasia officinalis, Oxalis acetosella, Plantago lanceolata, Veronica chamaedrys, Veronica officinalis, Polygala serpyllifolia, Rumex acetosa, Primula vulgaris, Anemone nemorosa, Ranunculus acris, Ranunculus repens, Potentilla erecta, Poterium sanguisorba, Galium saxatile, Galium verum, Viola lutea, Viola palustris, Viola riviniana, Agrostis canina, Agrostis capillaris, Alopecurus pratensis, Anthoxanthum odoratum, Avenula pratensis, Briza media, Cynosurus cristatus, Dactylis glomerata, Danthonia decumbens, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Holcus lanatus, Holcus mollis, Lolium perenne, Molinia caerulea, Nardus stricta, Poa annua, Poa pratensis, Blechnum spicant, Pteridium aquilinum, Chara curta

U5 — Upland acid grassland, Upland calcareous grassland

Nardus stricta-Galium saxatile grassland

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica cinerea, Erica tetralix, Vaccinium myrtillus, Carex bigelowii, Carex binervis, Carex demissa, Carex nigra, Carex panicea, Carex pilulifera, Carex pulicaris, Eriophorum angustifolium, Eriophorum vaginatum, Trichophorum cespitosum, Juncus effusus, Juncus squarrosus, Luzula campestris, Luzula multiflora, Luzula sylvatica, Huperzia selago, Selaginella selaginoides, Aulacomnium palustre, Pohlia nutans, Campylopus flexuosus, Dicranella heteromalla, Dicranum scoparium, Racomitrium lanuginosum, Calliergonell cuspidatum, Hylocomium splendens, Hypnum cupressiforme, Plagiothecium undulatum, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Thuidium tamariscinum, Polytrichastrum alpinum, Polytrichum commune, Polytrichum formosum, Polytrichum juniperinum, Sphagnum papillosum, Barbilophozia floerkei, Calypogeia muelleriana, Diplophyllum albicans, Lophocolea bidentata, Lophozia ventricosa, Pleurozia purpurea, Ptilidium ciliare, Scapania gracilis, Cetraria islandica, Cladonia uncialis, Cirsium palustre, Scorzoneroides autumnalis, Campanula rotundifolia, Cerastium fontanum, Equisetum palustre, Vaccinium vitis-idaea, Trifolium repens, Narthecium ossifragum, Plantago lanceolata, Polygala serpyllifolia, Anemone nemorosa, Ranunculus acris, Alchemilla alpina, Potentilla erecta, Galium saxatile, Viola riviniana, Agrostis capillaris, Agrostis vinealis, Anthoxanthum odoratum, Danthonia decumbens, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Molinia caerulea, Nardus stricta, Blechnum spicant