Craig y Rhiwarth
Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
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.
Habitats
Geology & landscape
Rock Type: Glacial Till, Limestone
Landscape processes: Coastal, Glacial
Description
Description The west-facing limestone escarpment of Craig y Rhiwarth on the east bank of the Afon Tawe, above Craig-y- nos, supports some of the finest limestone plant communities in Brecknock. The limestone is covered in places by acidic boulder clay, where communities of plants demanding more acidic conditions are confined and contrast with the calcicolous communities elsewhere. Ash woodland covers some of the screes, cliffs, steeper slopes and the sink hole to the south-west of Pwll-coediog. The best example of this habitat in Brecknock and one of the best in Britain, its notable ground flora includes lily-of-the-valley Convallaria majalis, wood spurge Euphorbia amygdaloides, wood fescue Festuca altissima, and the moss, Loeskeobryum brevirostre. Decaying logs support other notable mosses and liverworts such as Dicranodontium denudatum and Tritomaria exsectiformis, whilst the shrub layer includes such locally scarce shrubs as buckthorn Rhamnus cathartica. Ledges on the limestone cliff provide a refuge for nationally rare species of plants, for example the whitebeams, Sorbus leptophylla and the more widespread Sorbus porrigentiformis, and locally scarce species such as southern polypody Polypodium cambricum and the mosses, Seligeria acutifolia and Tortella nitida. Limestone grassland is well developed in openings of the canopy, with a large population of the rare soft-leaved sedge Carex montana and characteristic limestone plants such as small scabious Scabiosa columbaria, autumn gentian Gentianella amarella, and limestone bedstraw Galium sterneri. Areas of acidic glacial drift support contrasting oak and birch woodland and contribute to the great species diversity of the site, with over 170 species of higher plants and a similar number of lower plants known to grow here. Remarks: The site is within the Brecon Beacons National Park.
Species mentioned
Show the 16 species mentioned in the description, with red-list statusPlant communities
W10 — Atlantic oak wood, Lowland dry oak and birch wood, Lowland mixed oak and ash wood, Wood pasture
Quercus robur-Pteridium aquilinum-Rubus fruticosus woodland
Show 132 indicator speciesHedera helix, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Carpinus betulus, Corylus avellana, Fagus sylvatica, Castanea sativa, Quercus hybrid, Quercus petraea, Quercus robur, Tilia cordata, Tilia x europaea, Fraxinus excelsior, Larix decidua, Pinus nigra, Pinus sylvestris, Pseudotsuga menziesii, Malus sylvestris, Prunus avium, Sorbus aucuparia, Alnus glutinosa, Populus tremula, Taxus baccata, Ulmus glabra, Sambucus nigra, Viburnum lantana, Viburnum opulus, Rhododendron ponticum, Vaccinium myrtillus, Cytisus scoparius, Ulex europaeus, Ligustrum vulgare, Crataegus laevigata, Crataegus monogyna, Prunus spinosa, Carex sylvatica, Juncus effusus, Luzula multiflora, Luzula pilosa, Luzula sylvatica, Mnium hornum, Plagiomnium rostratum, Plagiomnium undulatum, Ceratodon purpureus, Dicranella heteromalla, Dicranoweisia cirrata, Dicranum scoparium, Amblystegium serpens, Brachythecium rutabulum, Eurhynchium striatum, Hypnum cupressiforme, Isothecium myosuroides, Kindbergia praelonga, Plagiothecium denticulatum, Plagiothecium undulatum, Pseudoscleropodium purum, Pseudotaxiphyllum elegans, Thuidium tamariscinum, Atrichum undulatum, Polytrichum formosum, Lophocolea bidentata, Pellia epiphylla, Narcissus pseudonarcissus, Aegopodium podagraria, Anthriscus sylvestris, Conopodium majus, Heracleum sphondylium, Sanicula europaea, Jacobaea vulgaris, Solidago virgaurea, Lonicera periclymenum, Silene dioica, Stellaria holostea, Stellaria media agg., Euphorbia amygdaloides, Mercurialis perennis, Corydalis claviculata, Geranium robertianum, Ajuga reptans, Glechoma hederacea, Lamiastrum galeobdolon, Stachys sylvatica, Teucrium scorodonia, Hyacinthoides non-scripta, Chamerion angustifolium, Circaea lutetiana, Oxalis acetosella, Digitalis purpurea, Veronica chamaedrys, Rumex acetosa, Rumex sanguineus, Lysimachia nemorum, Lysimachia nummularia, Primula vulgaris, Anemone nemorosa, Ficaria verna, Ranunculus repens, Fragaria vesca, Potentilla sterilis, Rosa canina, Rubus fruticosus agg., Rubus idaeus, Galium aparine, Galium odoratum, Galium saxatile, Melanpyrum pratense, Urtica dioica, Viola riviniana, Agrostis capillaris, Anthoxanthum odoratum, Arrhenatherum elatius, Brachypodium sylvaticum, Bromopsis ramosa, Dactylis glomerata, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Holcus lanatus, Holcus mollis, Melica uniflora, Milium effusum, Poa nemoralis, Poa trivialis, Blechnum spicant, Pteridium aquilinum, Dryopteris borreri, Dryopteris dilatata, Dryopteris filix-mas, Thelypteris limbosperma, Athyrium filix-femina
W16 — Atlantic oak wood, Lowland dry oak and birch wood, Wood pasture
Quercus spp.-Betula spp.-Deschampsia flexuosa woodland
Show 89 indicator speciesHedera helix, Acer pseudoplatanus, Ilex aquifolium, Betula pendula, Betula pubescens, Corylus avellana, Fagus sylvatica, Castanea sativa, Quercus hybrid, Quercus petraea, Quercus robur, Pinus sylvestris, Sorbus aria, Sorbus aucuparia, Populus tremula, Calluna vulgaris, Erica cinerea, Rhododendron ponticum, Vaccinium myrtillus, Ulex europaeus, Ulex gallii, Frangula alnus, Crataegus monogyna, Luzula sylvatica, Mnium hornum, Orthodontium lineare, Pohlia nutans, Campylopus flexuosus, Campylopus pyriformis, Dicranella heteromalla, Dicranodontium denudatum, Dicranoweisia cirrata, Dicranum fuscescens, Dicranum scoparium, Leucobryum glaucum, Hypnum cupressiforme, Hypnum jutlandicum, Isothecium myosuroides, Kindbergia praelonga, Plagiothecium denticulatum, Plagiothecium nemorale, Plagiothecium succulentum, Plagiothecium undulatum, Pleurozium schreberi, Pseudoscleropodium purum, Pseudotaxiphyllum elegans, Rhytidiadelphus loreus, Rhytidiadelphus triquetrus, Thuidium tamariscinum, Tetraphis pellucida, Barbilophozia attenuata, Barbilophozia floerkei, Calypogeia fissa, Calypogeia trichomanis, Cephalozia bicuspidata, Gymnocolea inflata, Lepidozia reptans, Lophocolea bidentata, Lophocolea heterophylla, Cladonia coccifera, Cladonia coniocraea, Cladonia fimbriata, Cladonia polydactyla, Cladonia squamosa, Solidago virgaurea, Lonicera periclymenum, Corydalis claviculata, Teucrium scorodonia, Hyacinthoides non-scripta, Chamerion angustifolium, Oxalis acetosella, Digitalis purpurea, Rumex acetosella, Potentilla erecta, Rubus fruticosus agg., Galium saxatile, Agrostis capillaris, Agrostis stolonifera, Anthoxanthum odoratum, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Holcus lanatus, Holcus mollis, Molinia caerulea, Blechnum spicant, Pteridium aquilinum, Dryopteris dilatata