Gweunydd Dolwen

Site of Special Scientific Interest · 52.6526, -3.5160

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Powys County

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Coastal

Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.

Geology & landscape

Geological Period: Silurian

Landscape processes: Coastal

Description

Description Gweunydd Dolwen is of special interest for its acid and neutral dry grassland. The site is located in central Montgomeryshire, some 4 km south-west of Llangadfan in the Nant yr Eira valley. It consists of two flat to gently undulating enclosures, lying on either side of the Afon Gam, at an altitude of between 210-220 m. This site occurs on a folded sequence of Silurian shales and sandstones ranging in age from youngest Llandovery (Telychian) to Wenlock (mid Sheinwoodian). The soils are mainly brown podzols which are stony and free draining. The stands of dry acid grassland are dominated by sheep’s fescue Festuca ovina and common bent Agrostis capillaris together with characteristic forbs such as betony Betonica officinalis, common bird’s-foot-trefoil Lotus corniculatus and bitter-vetch Lathyrus linifolius. In places heath bedstraw Galium saxatile and tormentil Potentilla erecta are frequent. In the more neutral grassland swards, plant species such as common knapweed Centaurea nigra, crested dog’s-tail Cynosurus cristatus and red clover Trifolium pratense are more frequent. Ranker grassland areas occur and these are characterised by the dominance of coarse grass species, typically false oat grass Arrhenatherum elatius and cock’s-foot Dactylis glomerata. Other plant species indicative of agriculturally unimproved grassland swards are present, including a population of the uncommon greater butterfly-orchid Platanthera chlorantha. Areas of dense scrub, gorse Ulex europaeus and river shingle occur within the site boundary. These contribute to the ecological diversity of the site, providing complementary habitat for invertebrates and other animals.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
common bent Agrostis capillaris LC grass poaceae
false oat grass Arrhenatherum elatius LC grass poaceae
crested dog's tail Cynosurus cristatus LC grass poaceae
cock's foot Dactylis glomerata LC grass poaceae
sheep's fescue Festuca ovina LC grass poaceae
betony Betonica officinalis VU herb lamiaceae
black knapweed Centaurea nigra LC herb asteraceae
heath bedstraw Galium saxatile LC herb rubiaceae
bitter vetch Lathyrus linifolius VU herb fabaceae
birdsfoot trefoil Lotus corniculatus LC herb fabaceae
greater butterfly orchid Platanthera chlorantha NT herb orchidaceae
tormentil Potentilla erecta LC herb rosaceae
red clover Trifolium pratense LC herb fabaceae
gorse Ulex europaeus LC shrub leguminosae

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

M25 — Blanket bog, Coastal floodplain grazing marsh, Lowland fen, Purple moor grass and rush pasture, Upland acid grassland

Molinia caerulea-Potentilla erecta mire

Salix cinerea, Calluna vulgaris, Erica tetralix, Myrica gale, Vaccinium oxycoccos, Ulex europaeus, Ulex gallii, Carex echinata, Carex flacca, Carex nigra, Carex panicea, Eriophorum angustifolium, Schoenus nigricans, Juncus acutiflorus, Juncus articulatus, Juncus effusus, Juncus subnodulosus, Luzula campestris, Luzula multiflora, Aulacomnium palustre, Pohlia nutans, Calliergon giganteum, Calliergonell cuspidatum, Hypnum jutlandicum, Kindbergia praelonga, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Polytrichum commune, Sphagnum auriculatum, Sphagnum capillifolium, Sphagnum fallax, Sphagnum palustre, Sphagnum papillosum, Sphagnum subnitens, Calypogeia fissa, Cephalozia bicuspidata, Lophocolea bidentata, Lophozia ventricosa, Angelica sylvestris, Carum verticillatum, Hydrocotyle vulgaris, Achillea ptarmica, Centaurea nigra, Cirsium palustre, Eupatorium cannabinum, Pulicaria dysenterica, Serratula tinctoria, Cardamine pratensis, Lobelia urens, Succisa pratensis, Valeriana officinalis, Equisetum palustre, Lotus pedunculatus, Hypericum pulchrum, Hypericum tetrapterum, Mentha aquatica, Scutellaria minor, Menyanthes trifoliata, Narthecium ossifragum, Epilobium palustre, Dactylorhiza maculata, Rumex acetosa, Ranunculus acris, Ranunculus flammula, Filipendula ulmaria, Potentilla erecta, Rubus fruticosus agg., Galium palustre, Viola palustris, Agrostis canina, Agrostis capillaris, Agrostis curtisii, Agrostis stolonifera, Anthoxanthum odoratum, Danthonia decumbens, Deschampsia cespitosa, Festuca ovina, Festuca rubra, Holcus lanatus, Molinia caerulea, Nardus stricta, Phragmites australis, Dryopteris carthusiana, Osmunda regalis

MC6 — Coastal vegetated shingle, Hard cliff and cliff slope

Atriplex prostrata-Beta vulgaris ssp. maritima sea-bird cliff community

Daucus carota, Sonchus oleraceus, Taraxacum officianalis, Tripleurospermum maritimum, Cochlearia officinalis, Silene uniflora, Spergularia rupicola, Atriplex hastata, Malva arborea, Plantago coronopus, Armeria maritima, Polygonum aviculare, Rumex crispus, Bromus hordeaceous, Catapodium marinum, Dactylis glomerata, Festuca rubra

SD1 — Coastal vegetated shingle, Sand dune

Rumex crispus-Glaucium flavum shingle community

Solanum dulcamara, Crithmum maritimum, Cirsium arvense, Cirsium vulgare, Helminthotheca echioides, Hypochaeris radicata, Jacobaea vulgaris, Lactuca serriola, Leontodon saxatilis, Senecio viscosus, Sonchus arvensis, Sonchus asper, Tripleurospermum maritimum, Crambe maritima, Cerastium fontanum, Honckenya peploides, Sagina apetala, Silene uniflora, Atriplex prostrata, Sedum acre, Euphorbia paralias, Lathyrus japonicus, Geranium robertianum, Glaucium flavum, Plantago coronopus, Plantago lanceolata, Rumex crispus, Potentilla anserina, Ammophila arenaria, Arrhenatherum elatius, Elytrigia atherica, Elytrigia juncea, Festuca rubra, Holcus lanatus, Lolium perenne

SD2 — Coastal vegetated shingle, Sand dune

Honkenya peploides-Cakile maritima strandline community

Salsola kali, Achillea millefolium, Cirsium arvense, Eryngium maritimum, Hypochaeris radicata, Senecio vulgaris, Sonchus arvensis, Tripleurospermum maritimum, Cakile maritima, Cerastium diffusum, Honckenya peploides, Silene uniflora, Stellaria media agg., Atriplex glabriuscula, Atriplex laciniata, Atriplex littoralis, Atriplex patula, Atriplex prostrata, Sedum acre, Polygonum oxyspermum subsp. Raii, Rumex crispus, Potentilla anserina, Agrostis stolonifera, Ammophila arenaria, Arrhenatherum elatius, Elytrigia juncea, Elytrigia repens, Festuca rubra, Leymus arenarius, Poa annua

SD3 — Coastal vegetated shingle, Sand dune

Matricaria maritima-Galium aparine strandline community

Bolboschoenus maritimus, Juncus bufonius, Juncus gerardii, Ligusticum scoticum, Matricaria discoidea, Sonchus arvensis, Sonchus asper, Tripleurospermum maritimum, Mertensia maritima, Cakile maritima, Cochlearia officinalis, Honckenya peploides, Stellaria media agg., Atriplex glabriuscula, Atriplex patula, Atriplex prostrata, Triglochin maritimum, Plantago maritima, Armeria maritima, Rumex crispus, Glaux maritima, Galium aparine, Agrostis stolonifera, Elytrigia repens, Festuca rubra, Holcus lanatus, Leymus arenarius, Poa annua

U2 — Brownfield, Lowland dry acid grassland, Upland acid grassland

Deschampsia flexuosa grassland

Betula pendula, Quercus hybrid, Empetrum nigrum subsp.nigrum, Calluna vulgaris, Vaccinium myrtillus, Ulex europaeus, Carex nigra, Eriophorum vaginatum, Juncus effusus, Juncus squarrosus, Luzula multiflora, Orthodontium lineare, Pohlia nutans, Campylopus pyriformis, Dicranum scoparium, Hypnum cupressiforme, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus squarrosus, Polytrichum commune, Polytrichum piliferum, Barbilophozia floerkei, Cladonia gracilis, Chamerion angustifolium, Rumex acetosa, Rumex acetosella, Potentilla erecta, Rubus fruticosus agg., Galium saxatile, Agrostis capillaris, Agrostis vinealis, Anthoxanthum odoratum, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Holcus mollis, Molinia caerulea, Nardus stricta, Poa annua, Pteridium aquilinum

U3 — Lowland dry acid grassland, Upland acid grassland

Agrostis curtisii grassland

Calluna vulgaris, Erica cinerea, Erica tetralix, Vaccinium myrtillus, Ulex europaeus, Ulex gallii, Carex binervis, Carex panicea, Carex pilulifera, Luzula campestris, Dicranum scoparium, Hylocomium splendens, Hypnum cupressiforme, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Cladonia floerkeana, Cladonia impexa, Hypochaeris radicata, Teucrium scorodonia, Polygala serpyllifolia, Potentilla erecta, Galium saxatile, Agrostis capillaris, Agrostis curtisii, Agrostis vinealis, Anthoxanthum odoratum, Danthonia decumbens, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Molinia caerulea, Nardus stricta, Pteridium aquilinum

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

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