Llanelwedd Rocks

Site of Special Scientific Interest · 52.1613, -3.3885

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Also within

Powys County

Habitats

Bracken scrub, Mixed scrub, Montane scrub

Geology & landscape

Geological Feature: Geological Fault · Mining / Industrial: Quarry · Geological Period: Ordovician · Rock Type: Andesite, Basalt, Rhyolite

Landscape processes: Volcanic / Igneous

Birds & fish recorded

Fish

SpeciesSeason
Grayling Unknown

Description

Description Geological: Caledonian Structures of Wales: The quarry provides the best exposed section across the structures of the Pontesford Lineament, one of the major fault belts that was active between the Welsh Basin and the Midland Platform of England in Palaeozoic time. It exposed rocks of the Builth Igneous Complex, of Llanvirn (Ordovician) age, at the southern end of the Builth-Llandrindod Inlier. The quarry is important in demonstrating exposure through the fault belt in an area of otherwise poor exposure. It demonstrates the importance of strike-slip faulting during a deformation event of probable Ashgill (late Ordovician) age that might have involved large lateral displacements. The geometry of the fault systems at the locality is also of some general interest in understanding the mechanics of strike-slip tectonics. Ordovician Igneous: The Builth-Llandrindod Inlier also shows exposures which reveal the character of an Ordovician volcanic suite erupted and emplaced during Llanvirn times. The suite spans the basalt-andesite-rhyolite compositional range and consequently is geochemically different from typical sequences of similar age elsewhere in Wales. The basaltic lavas are present in both massive and pillowed forms and hyaloclastic rocks are also locally present. The rocks of intermediate and acidic composition occur as lava flows, high-level contemporaneous intrusions, and dacitic to rhyolitic ash-flow and air-fall tuffs. The volcanic rocks present in this site are critical to an understanding of volcanic activity in Wales during the lower Palaeozoic era. Biological: A nationally uncommon vegetation type is present on natural rock outcrops and old quarry exposures. It has affinities with steppe-heath vegetation types, and in mid-Wales is associated with the presence of one or more of four uncommon species, namely maiden pink Dianthus deltoides, upright chickweed Moenchia erecta, bird’s foot Ornithopus perpusillus and annual knawel Scleranthus annuus. At Llanelwedd, good populations of upright chickweed and bird’s-foot occur, and maiden pink is also present in one locality. The other species which occur with these rare plants, namely wild thyme Thymus praecox, lady’s bedstraw Galium verum, common whitlowgrass Erophila verna and squirrel-tail fescue Vulpia bromoides, and locally sticky stork’s-bill Erodium cicutarium and orpine Sedum telephium, are characteristic of a more widespread plant community to be found on thin, well-drained and relatively basic soils. The area is also noted for its diversity of forms of lesser dandelion Taraxacum laevigatum (section Erythrosperma), with six micro-species having been recorded. The complete successional sequence from grassland to mixed scrub over false brome Brachypodium sylvaticum, and the to oak/ash woodland in which the ground layer is often dominated by bracken Pteridium aquilinum, is well represented throughout the site. Many of the lower rock outcrops support a rich lichen and moss flora with a number of locally uncommon species, e.g. Parmelia brittanica, Fuscidea recensa and F. praeruptorum. The occurrence of deeper soils, spring flushes or mineral flushes all contributes to a diversity of grassland types, with probably the greatest diversity of flowering plants to be found anywhere in Radnor. The diversity of habitat at this site is particularly valuable for small birds and insects. There is abundant cover for passerines and Lepidoptera, including silver-washed fritillary Argynnis paphia, large skipper Ochlodes venata and chimney sweep moth Odezia atrata. The grayling Hipparchia semele, a butterfly which is very rare in mid-Wales, also occurs. Woodlark has not been present in recent years, but formerly Llanelwedd was the only known Welsh locality for this species.

Species mentioned

English name
search for this in other sites		 Latin name
search with Google		 IUCN / Red List Type Family
silver-washed fritillary Argynnis paphia LC butterfly nymphalidae
grayling Hipparchia semele EN butterfly nymphalidae
bracken Pteridium aquilinum LC fern dennstaedtiaceae
wood false brome Brachypodium sylvaticum LC grass poaceae
squirrel tail fescue Vulpia bromoides LC grass poaceae
maiden pink Dianthus deltoides NT herb carophyllaceae
common stork's bill Erodium cicutarium LC herb hydrobiidae
Whitlow grasses Erophila verna LC herb brassicaceae
lady's bedstraw Galium verum LC herb rubiaceae
upright chickweed Moenchia erecta VU herb carophyllaceae
bird's foot Ornithopus perpusillus LC herb fabaceae
annual knawel Scleranthus annuus DD herb carophyllaceae
orpine Sedum telephium Not listed in GB list herb crassulaceae
rock dandylion Taraxacum laevigatum Not listed in GB list herb asteraceae
creeping thyme Thymus praecox Not listed in GB list herb lamiaceae
chimney sweeper Odezia atrata Not listed in GB list moth geometridae

Plant communities

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

W25 — Bracken scrub

Pteridium aquilinum-Rubus fruticosus underscrub

Hedera helix, Acer pseudoplatanus, Fagus sylvatica, Quercus robur, Fraxinus excelsior, Sambucus nigra, Ulex europaeus, Crataegus monogyna, Prunus spinosa, Luzula multiflora, Mnium hornum, Brachythecium rutabulum, Kindbergia praelonga, Angelica sylvestris, Conopodium majus, Heracleum sphondylium, Arum maculatum, Cirsium arvense, Lonicera periclymenum, Silene dioica, Stellaria holostea, Mercurialis perennis, Geranium robertianum, Glechoma hederacea, Teucrium scorodonia, Hyacinthoides non-scripta, Chamerion angustifolium, Circaea lutetiana, Digitalis purpurea, Rumex acetosa, Anemone nemorosa, Ficaria verna, Potentilla erecta, Rosa arvensis, Rosa canina, Rubus fruticosus agg., Rubus idaeus, Galium aparine, Galium mollugo sens.lat., Galium saxatile, Urtica dioica, Viola riviniana, Agrostis capillaris, Anthoxanthum odoratum, Arrhenatherum elatius, Dactylis glomerata, Festuca rubra, Holcus lanatus, Holcus mollis, Poa trivialis, Pteridium aquilinum, Dryopteris dilatata, Dryopteris filix-mas