Lydford Gorge

Site of Special Scientific Interest · 50.6356, -4.1182

Condition (Natural England)

Unfavourable Declining (7)
UnitFeatureConditionArea (ha)Assessed
SX502835 Unfavourable Declining 0.21 2024-03-05
SX502839 Unfavourable Declining 32.73 2024-03-05
SX503835 Unfavourable Declining 0.58 2024-03-05
SX503836 Unfavourable Declining 0.2 2024-03-05
SX503837 Unfavourable Declining 2.16 2024-03-05
SX504842 Unfavourable Declining 0.35 2024-03-05
SX511846 Unfavourable Declining 32.73 2024-03-05

Geology & landscape

Geological Feature: Gorge / Ravine · Geological Period: Carboniferous, Devonian

Landscape processes: Fluvial

Birds & fish recorded

Birds

SpeciesSeason
buzzard Breeding
grey wagtail Breeding
wood warbler Breeding
yellow wagtail Breeding

Description

Lydford Gorge SSSI Description Lydford Gorge combines features associated with gorge formation and ‘river capture’ with fine examples of ancient oak-hazel woodland developed on the steep slopes. The site is also important for its bryophytes and supports several uncommon moss species. The Gorge, formed by the River Lyd and lying on the Carboniferous Culm measures of the north-western edge of Dartmoor, has a depth of some 35 metres and is almost two kilometres in length. It provides excellent exposures of dark slates of Devonian age. Recent detailed geological study has revealed the presence of two major flat lying dislocations (thrusts) now known as the Manor Hotel Thrust and Lydford Thrust. Compression of the earth’s crust during the Hercynian mountain building episode (orogeny) formed these major dislocations, along with adjoining rock successions were stacked one above another. This recent work has revealed a much more complex picture of the geological make-up of this area, owing to the presence of these thrusts, than was formerly recognised and the outcrops in the Lydford Gorge are especially important in providing the only known exposures of the Lydford Thrust. The thrust separates two major rock units known as the Liddaton Slates and the Lydford Formation. The site also includes the definitive exposures of the Manor Hotel Beds which contain important fossil remains, critical to the accurate dating of these beds. This site is of considerable importance in interpreting the rock succession and structure of an area of complex geology. Geomorphologically, the site displays a fine range of features associated with rejuvenation, including the gorge itself, an impressive waterfall and the fluted imprints of ancient potholes many metres above present river level. The steep valley sides bear thin soils and are clothed by ancient woodland dominated by pedunculate oak Quercus robur, together with occasional ash Fraxinus excelsior and with an understorey which is comprised mainly of hazel Corylus avellana and holly Ilex aquifolium. The woodland canopy is generally open and an extremely diverse ground flora has developed. This includes wood anemone Anemone nemorosa, woodruff Galium odoratum, bluebell Hyacinthoides non-scripta and, on the more acid slopes, great woodrush Luzula sylvatica and bilberry Vaccinium myrtillus. Wet flushes on the lower slopes are characterised by opposite-leaved golden saxifrage Chrysosplenium oppositifolium, while where the gorge is at its deepest near Lydford Bridge, the precipitous slopes support a varied fern flora. Wood melick Melica uniflora, ramsons Allium ursinum and other base-demanding species occur on the ledges and beside the river. The splash zones and the upper slopes of the gorge support a luxuriant bryophyte community which includes the uncommon Mnium stellare, Trichocolea tomentella and Isothecium holtii. Sheets of the uncommon lichen Sticta canariensis (Dufourii) also occur on damp rocks. The site supports a breeding bird community characteristic of Devon valley oak woods including raven Corvus corax, buzzard Buteo buteo and wood warbler Phylloscopus sibilatrix. Grey wagtail Motacilla flava and dipper Cinclus cinclus breed beside the river, which is also frequented by otters Lutra lutra.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
raven Corvus corax LC (Breeding) bird-corvid corvidae
dipper Cinclus cinclus NT (Breeding) bird-dipper cinclidae
buzzard Buteo buteo LC (Breeding) bird-hawk falconidae
yellow wagtail Motacilla flava NT (Breeding) bird-wagtail motacillidae
wood warbler Phylloscopus sibilatrix VU (Breeding) bird-warbler phylloscopidae
otter Lutra lutra LC carnivore mustelidae
wood melick Melica uniflora NT grass poaceae
ramson Allium ursinum LC herb liliaceae
wood anemone Anemone nemorosa LC herb ranunculaceae
opposite-leaved golden- saxifrage Chrysosplenium oppositifolium LC herb saxifragaceae
woodruff Galium odoratum LC herb rubiaceae
bluebell Hyacinthoides non-scripta LC herb liliaceae
no common name Sticta canariensis LC, VU lichen no common name
handsome woolywort Trichocolea tomentella LC liverwort jungermanniales
Holt's mouse-tail moss Isothecium holtii LC moss hypnales
starry thyme moss Mnium stellare LC moss bryales
great wood rush Luzula sylvatica LC rush juncaceae
billberry Vaccinium myrtillus LC shrub ericaceae
hazel Corylus avellana LC tree corylaceae
ash Fraxinus excelsior LC tree oleaceae
holly Ilex aquifolium LC tree aquifoliaceae
common oak Quercus robur LC tree fagaceae

Plant communities

A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream

Potamogeton natans community

Schoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa

A14 — Fast flowing river and stream

Myriophyllum alterniflorum community

Isolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina

A17 — Chalk river and stream, Fast flowing river and stream

Ranunculus penicillatus ssp. pseudofluitans community

Berula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans

A18 — Fast flowing river and stream

Ranunculus fluitans community

Fontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea

W9 — Altantic hazel wood, Limestone pavement, Upland mixed ash wood

Fraxinus excelsior-Sorbus aucuparia-Mercurialis perennis woodland

Hedera helix, Salix cinerea, Acer campestre, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Corylus avellana, Fagus sylvatica, Quercus hybrid, Quercus petraea, Quercus robur, Fraxinus excelsior, Pinus sylvestris, Prunus padus, Sorbus aucuparia, Alnus glutinosa, Populus tremula, Ulmus glabra, Sambucus nigra, Crataegus monogyna, Rubus saxatilis, Carex pallescens, Carex sylvatica, Luzula sylvatica, Mnium hornum, Plagiomnium rostratum, Plagiomnium undulatum, Rhizomnium punctatum, Dicranum scoparium, Fissidens curnovii, Fissidens taxifolius, Brachythecium rutabulum, Cirriphyllum piliferum, Ctenidium molluscum, Eurhynchium striatum, Hylocomium splendens, Hypnum cupressiforme, Isothecium alopecuroides, Isothecium myosuroides, Kindbergia praelonga, Loeskeobryum brevirostre, Oxyrrhynchium hians, Plagiothecium denticulatum, Plagiothecium succulentum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Thuidium delicatulum, Thuidium tamariscinum, Atrichum undulatum, Polytrichum formosum, Lophocolea bidentata, Plagiochila asplenioides, Pellia endiviifolia, Pellia epiphylla, Adoxa moschatellina, Angelica sylvestris, Anthriscus sylvestris, Conopodium majus, Heracleum sphondylium, Sanicula europaea, Arum maculatum, Cirsium heterophyllum, Cirsium palustre, Crepis paludosa, Jacobaea vulgaris, Tussilago farfara, Cardamine flexuosa, Succisa pratensis, Valeriana officinalis, Silene dioica, Stellaria holostea, Mercurialis perennis, Vicia sepium, Geranium robertianum, Geranium sylvaticum, Ajuga reptans, Lamiastrum galeobdolon, Stachys sylvatica, Allium ursinum, Hyacinthoides non-scripta, Circaea lutetiana, Circaea x intermedia, Epilobium montanum, Oxalis acetosella, Digitalis purpurea, Veronica chamaedrys, Veronica montana, Rumex acetosa, Lysimachia nemorum, Primula vulgaris, Anemone nemorosa, Ficaria verna, Ranunculus acris, Ranunculus repens, Trollius europaeus, Alchemilla glabra, Alchemilla xanthochlora, Filipendula ulmaria, Fragaria vesca, Geum rivale, Geum urbanum, Potentilla erecta, Potentilla sterilis, Rosa canina, Rubus fruticosus agg., Rubus idaeus, Cruciata laevipes, Galium aparine, Galium odoratum, Galium saxatile, Chrysosplenium oppositifolium, Urtica dioica, Viola riviniana, Agrostis capillaris, Agrostis stolonifera, Anthoxanthum odoratum, Arrhenatherum elatius, Brachypodium sylvaticum, Bromopsis ramosa, Dactylis glomerata, Deschampsia cespitosa, Holcus lanatus, Holcus mollis, Melica uniflora, Milium effusum, Poa trivialis, Schedonorus giganteus, Asplenium scolopendrium, Blechnum spicant, Pteridium aquilinum, Dryopteris borreri, Dryopteris dilatata, Dryopteris filix-mas, Athyrium filix-femina

W11 — Altantic hazel wood, Atlantic oak wood, Caledonian forest, Upland birch wood, Wood pasture

Quercus petraea-Betula pubescens-Oxalis acetosella woodland

Acer campestre, Ilex aquifolium, Betula pendula, Betula pubescens, Corylus avellana, Fagus sylvatica, Quercus hybrid, Quercus petraea, Quercus robur, Fraxinus excelsior, Larix decidua, Sorbus aucuparia, Calluna vulgaris, Erica cinerea, Juniperus communis, Vaccinium myrtillus, Cytisus scoparius, Crataegus monogyna, Rubus saxatilis, Carex pilulifera, Luzula campestris, Luzula multiflora, Luzula pilosa, Luzula sylvatica, Mnium hornum, Plagiomnium affine, Plagiomnium undulatum, Dicranum majus, Dicranum scoparium, Cirriphyllum piliferum, Eurhynchium striatum, Hylocomium splendens, Hypnum cupressiforme, Isothecium myosuroides, Kindbergia praelonga, Loeskeobryum brevirostre, Plagiothecium denticulatum, Plagiothecium undulatum, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Thuidium tamariscinum, Atrichum undulatum, Polytrichum commune, Polytrichum formosum, Polytrichum longisetum, Sphagnum capillifolium, Diplophyllum albicans, Lophocolea bidentata, Plagiochila asplenioides, Plagiochila spinulosa, Angelica sylvestris, Conopodium majus, Campanula rotundifolia, Lonicera periclymenum, Succisa pratensis, Cerastium fontanum, Stellaria holostea, Pyrola minor, Vaccinium vitis-idaea, Lathyrus montanus, Geranium robertianum, Hypericum pulchrum, Ajuga reptans, Teucrium scorodonia, Convallaria majalis, Hyacinthoides non-scripta, Oxalis acetosella, Digitalis purpurea, Veronica chamaedrys, Veronica officinalis, Rumex acetosa, Lysimachia nemorum, Primula vulgaris, Trientalis europaea, Anemone nemorosa, Ranunculus acris, Ranunculus repens, Potentilla erecta, Rubus fruticosus agg., Rubus idaeus, Galium aparine, Galium saxatile, Melanpyrum pratense, Viola riviniana, Agrostis capillaris, Agrostis vinealis, Anthoxanthum odoratum, Brachypodium sylvaticum, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Holcus lanatus, Holcus mollis, Poa pratensis, Poa trivialis, Blechnum spicant, Pteridium aquilinum, Dryopteris borreri, Dryopteris dilatata, Dryopteris filix-mas, Thelypteris limbosperma, Athyrium filix-femina

W17 — Altantic hazel wood, Atlantic oak wood, Caledonian forest, Upland birch wood, Wood pasture

Quercus petraea-Betula pubescens-Dicranum majus woodland

Hedera helix, Salix caprea, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Corylus avellana, Fagus sylvatica, Quercus hybrid, Quercus petraea, Quercus robur, Fraxinus excelsior, Sorbus aucuparia, Calluna vulgaris, Erica cinerea, Erica tetralix, Juniperus communis, Rhododendron ponticum, Vaccinium myrtillus, Crataegus monogyna, Carex pilulifera, Luzula multiflora, Luzula pilosa, Luzula sylvatica, Andreaea rupestris, Mnium hornum, Rhizomnium punctatum, Campylopus flexuosus, Dicranella heteromalla, Dicranodontium denudatum, Dicranum fuscescens, Dicranum majus, Dicranum scoparium, Dicranum scottianum, Leucobryum glaucum, Ptychomitrium polyphyllum, Racomitrium fasciculare, Racomitrium heterostichum, Racomitrium lanuginosum, Eurhynchium striatum, Heterocladium heteropterum, Hylocomiastrum umbratum, Hylocomium armoricum, Hylocomium splendens, Hypnum callichroum, Hypnum cupressiforme, Hypnum jutlandicum, Isothecium myosuroides, Kindbergia praelonga, Loeskeobryum brevirostre, Plagiothecium denticulatum, Plagiothecium undulatum, Pleurozium schreberi, Pseudoscleropodium purum, Pseudotaxiphyllum elegans, Ptilium crista-castrensis, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sematophyllum demissum, Sematophyllum micans, Thuidium delicatulum, Thuidium tamariscinum, Polytrichum commune, Polytrichum formosum, Sphagnum capillifolium, Sphagnum fimbriatum, Sphagnum palustre, Sphagnum russowii, Sphagnum subnitens, Tetraphis pellucida, Adelanthus decipiens, Anastrepta orcadensis, Barbilophozia attenuata, Barbilophozia floerkei, Bazzania tricrenata, Bazzania trilobata, Blepharostoma trichophyllum, Calypogeia fissa, Calypogeia muelleriana, Cephalozia bicuspidata, Diplophyllum albicans, Frullania tamarisci, Fuscocephaloziopsis lunulifolia, Harpanthus scutatus, Jamesoniella autumnalis, Jungermannia gracillima, Lepidozia pearsonii, Lepidozia reptans, Lophocolea bidentata, Lophocolea heterophylla, Lophozia ventricosa, Marsupella emarginata, Microlejeunea ulicina, Mylia taylorii, Nowellia curvifolia, Plagiochila asplenioides, Plagiochila atlantica, Plagiochila killarniensis, Plagiochila porelloides, Plagiochila punctata, Plagiochila spinulosa, Ptilidium ciliare, Saccogyna viticulosa, Scapania gracilis, Scapania nemorea, Scapania umbrosa, Tritomaria exsectiformis, Tritomaria quinquedentata, Cladonia arbuscula, Cladonia chlorophaea, Cladonia digitata, Cladonia furcata, Cladonia impexa, Cladonia polydactyla, Cladonia squamosa, Cladonia squamules, Cladonia subcervicornis, Parmelia saxatilis, Sphaerophorus fragilis, Sphaerophorus globosus, Solidago virgaurea, Lonicera periclymenum, Succisa pratensis, Cornus suecica, Hypericum pulchrum, Teucrium scorodonia, Hyacinthoides non-scripta, Goodyera repens, Oxalis acetosella, Digitalis purpurea, Rumex acetosa, Lysimachia nemorum, Trientalis europaea, Anemone nemorosa, Potentilla erecta, Rubus fruticosus agg., Rubus idaeus, Galium saxatile, Melanpyrum pratense, Viola riviniana, Agrostis capillaris, Agrostis stolonifera, Agrostis vinealis, Anthoxanthum odoratum, Dactylis glomerata, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Holcus lanatus, Holcus mollis, Molinia caerulea, Poa nemoralis, Poa pratensis, Blechnum spicant, Pteridium aquilinum, Dryopteris aemula, Dryopteris borreri, Dryopteris dilatata, Dryopteris filix-mas, Hymenophyllum tunbrigense, Hymenophyllum wilsonii, Polypodium vulgare, Thelypteris limbosperma, Athyrium filix-femina