Coed Blaen-y-cwm (Blaen-y-cwm Wood)

Site of Special Scientific Interest · 52.0254, -3.1557

Geology & landscape

Rock Type: Sandstone

Birds & fish recorded

Birds

SpeciesSeason
blackcap Breeding
pied flycatcher Breeding
wood warbler Breeding

Description

Description The site comprises a semi-natural woodland dominated in pat by mixtures of ash, wych elm, sessile oak and field maple. This combination of canopy species is nationally rare, with the majority of examples occurring on the Old Red Sandstone of the Welsh Marches. The wood appears to have had a somewhat chequered history with at least one small area converted to pasture and other parts suffering clear felling and/or the introduction of conifers in the past. However, the disturbance has not apparently been great enough to impoverish the site, with known sensitive species such as lichens still well represented (41 epiphytic species) and included amongst them a few species such as Thelotrema lepadinum, known to be poor colonizers of cleared sites. The age range of trees is also considerable, with a number of old oaks present and also areas of dense young sapling growth. To date 133 species of higher plants and 70 species of mosses and liverworts have been recorded from the site.The wood has developed on moist, somewhat calcareous soils on a steep south-west facing bank. Springs occur along the lower slopes, producing wet flushed areas, whilst rock outcrops are confined to the upper slopes and banks beside the stream and in the stream itself. Being ungrazed, the moister slopes bear a notably rich ground flora, including early-purple orchid Orchis mascula, herb-Paris Paris quadrifolia, giant bellflower Campanula latifolia, primrose Primula vulgaris and meadow saffron Colchicum autumnale amongst the more common woodland herbs such as yellow archangel Lamiastrum galeobdolon, dog's mercury Mercurialis perennis, wood-sorrel Oxalis acetosella and enchanter's-nightshade Circaea lutetiana. The upper slopes are more acidic, supporting species such as wood sage Teucrium scorodonia and common cow-wheat Melampyrum pratense. Lime-rich rock outcrops support a number of calcicolous plant species such as hairy St John's-wort Hypericum hirsutum and the mosses Anomodon viticulosus and Neckera crispa. The warm sunny glades close to the stream where these species occur are particularly attractive for butterflies, with such species as silver-washed fritillary Argynnis paphia, hedge brown Pyronia tithonus and speckled wood Pararge aegeria noted in some abundance in 1984. The wood supports a notable variety of breeding birds, including wood warbler, blackcap, tawny owl and pied flycatcher. Dippers are found on the stream. Remarks: The site lies within Brecon Beacons National Park.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
tawny owl Strix aluco NT (Breeding) bird-owl strigidae
pied flycatcher Ficedula hypoleuca VU (Breeding) bird-robin muscicapidae
wood warbler Phylloscopus sibilatrix VU (Breeding) bird-warbler phylloscopidae
blackcap Sylvia atricapilla LC (Breeding) bird-warbler sylviidae
silver-washed fritillary Argynnis paphia LC butterfly nymphalidae
speckled wood Pararge aegeria LC butterfly nymphalidae
gatekeeper Pyronia tithonus LC butterfly nymphalidae
giant bellflower Campanula latifolia VU herb campanulaceae
enchanter's nightshade Circaea lutetiana LC herb onagraceae
autumn crocus or meadow saffron Colchicum autumnale NT herb colchicaceae
hairy St John's wort Hypericum hirsutum LC herb hypericaceae
yellow archangel Lamiastrum galeobdolon LC herb lamiaceae
common cowwheat Melampyrum pratense VU herb orobanchaceae
dog's mercury Mercurialis perennis LC herb euphorbiaceae
early purple orchid Orchis mascula LC herb orchidaceae
wood sorrel Oxalis acetosella LC herb oxalidaceae
herb paris Paris quadrifolia VU herb melanthiaceae
primrose Primula vulgaris LC herb primulaceae
wood sage Teucrium scorodonia LC herb lamiaceae
barnacle lichen Thelotrema lepadinum LC lichen no common name
rambling tail moss Anomodon viticulosus LC moss hypnales
crisped neckera Neckera crispa LC moss hypnales

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

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

W23 — Brownfield, Hedgerow scrub

Ulex europaeus-Rubus fruticosus scrub

Hedera helix, Calluna vulgaris, Cytisus scoparius, Ulex europaeus, Kindbergia praelonga, Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Achillea millefolium, Crepis capillaris, Hypochaeris radicata, Jacobaea vulgaris, Campanula rotundifolia, Jasione montana, Cerastium fontanum, Silene dioica, Teucrium scorodonia, Digitalis purpurea, Plantago lanceolata, Veronica chamaedrys, Veronica officinalis, Rumex acetosa, Rumex acetosella, Potentilla erecta, Rubus fruticosus agg., Rubus idaeus, Galium saxatile, Viola riviniana, Agrostis capillaris, Aira praecox, Anthoxanthum odoratum, Arrhenatherum elatius, Brachypodium sylvaticum, Dactylis glomerata, Deschampsia flexuosa, Festuca rubra, Holcus lanatus, Holcus mollis, Poa pratensis, Pteridium aquilinum