Beacon Bog

Site of Special Scientific Interest · 51.8243, -4.3906

Also within

Dyfed County

Climate exposure

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

Peatland

Peat habitats store centuries of carbon and depend on a stable, waterlogged water table. Warmer, drier summers dry out peat, making it far more vulnerable to wildfire and to carbon release — a pressure that can undo years of restoration work regardless of how well the site is otherwise managed.

Habitats

Blanket bog

Geology & landscape

Landscape processes: Peatland / Mire

Description

Description A basin mire with a small catchment. The peat is up to 2 metres deep near the centre. The surface is very wet with active growth of bog mosses Sphagnum spp. Several scarce plants occur, notably bog rosemary Andromeda polifolia near its most southerly known location in the British Isles. Others are royal fern Osmunda regalis, cranberry Vaccinium oxycoccos and petty whin Genista anglica. The latter grows on the drier western margin. Purple moor-grass Molinia caerulea dominates the drier edges of the site. Remarks: Registered as common land.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
royal fern Osmunda regalis LC fern osmundaceae
purple moor grass Molinia caerulea LC grass poaceae
petty whin Genista anglica EN herb fabaceae
bog moss Sphagnum spp. Not listed in GB list moss sphagnales
bog rosemary Andromeda polifolia LC shrub ericaceae
cranberry Vaccinium oxycoccos LC shrub ericaceae

Plant communities

M18 — Blanket bog, Raised bog

Erica tetralix-Sphagnum papillosum raised and blanket mire

Matches 3 species from the description above: Andromeda polifolia, Molinia caerulea, Vaccinium oxycoccos

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica tetralix, Myrica gale, Andromeda polifolia, Vaccinium myrtillus, Vaccinium oxycoccos, Eriophorum angustifolium, Eriophorum vaginatum, Rhynchospora alba, Trichophorum cespitosum, Juncus squarrosus, Aulacomnium palustre, Pohlia nutans, Campylopus flexuosus, Dicranum scoparium, Racomitrium lanuginosum, Hypnum cupressiforme, Hypnum jutlandicum, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus loreus, Polytrichum commune, Polytrichum strictum, Sphagnum capillifolium, Sphagnum cuspidatum, Sphagnum fallax, Sphagnum fuscum, Sphagnum magellanicum, Sphagnum palustre, Sphagnum papillosum, Sphagnum pulchrum, Sphagnum subnitens, Sphagnum tenellum, Calypogeia muelleriana, Cephalozia bicuspidata, Cephalozia connivens, Cladopodiella fluitans, Kurzia pauciflora, Lophozia ventricosa, Mylia anomala, Ordontoschisma sphagni, Hypogymnia physodes, Cladonia arbuscula, Cladonia gracilis, Cladonia impexa, Cladonia uncialis, Drosera anglica, Drosera rotundifolia, Vaccinium vitis-idaea, Narthecium ossifragum, Rubus chamaemorus, Deschampsia flexuosa, Molinia caerulea

M2 — Blanket bog, Raised bog, Valley mire

Sphagnum cuspidatum/recurvum bog pool community

Matches 3 species from the description above: Andromeda polifolia, Molinia caerulea, Vaccinium oxycoccos

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica tetralix, Myrica gale, Andromeda polifolia, Vaccinium oxycoccos, Carex canescens, Carex magellanica, Carex rostrata, Eriophorum angustifolium, Eriophorum vaginatum, Rhynchospora alba, Aulacomnium palustre, Polytrichum commune, Polytrichum strictum, Sphagnum cuspidatum, Sphagnum fallax, Sphagnum magellanicum, Sphagnum palustre, Sphagnum papillosum, Sphagnum pulchrum, Sphagnum tenellum, Cephalozia connivens, Cephalozia lunulifolia, Gymnocolea inflata, Mylia anomala, Ordontoschisma sphagni, Cladonia impexa, Cladonia uncialis, Drosera anglica, Drosera intermedia, Drosera rotundifolia, Menyanthes trifoliata, Narthecium ossifragum, Agrostis canina, Deschampsia flexuosa, Molinia caerulea

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

Molinia caerulea-Potentilla erecta mire

Matches 3 species from the description above: Molinia caerulea, Osmunda regalis, Vaccinium oxycoccos

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

M19 — Blanket bog, Raised bog

Calluna vulgaris-Eriophorum vaginatum blanket mire

Matches 2 species from the description above: Molinia caerulea, Vaccinium oxycoccos

Empetrum nigrum, Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica tetralix, Betula nana, Arctostaphylos alpinus, Vaccinium microcarpum, Vaccinium myrtillus, Vaccinium oxycoccos, Vaccinium uliginosum, Carex bigelowii, Carex binervis, Carex nigra, Eriophorum angustifolium, Eriophorum vaginatum, Trichophorum cespitosum, Juncus squarrosus, Luzula sylvatica, Huperzia selago, Aulacomnium palustre, Pohlia nutans, Campylopus flexuosus, Dicranum fuscescens, Dicranum majus, Dicranum scoparium, Racomitrium lanuginosum, Hylocomium splendens, Hypnum cupressiforme, Hypnum jutlandicum, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Polytrichastrum alpinum, Polytrichum commune, Polytrichum strictum, Sphagnum capillifolium, Sphagnum compactum, Sphagnum fallax, Sphagnum fuscum, Sphagnum palustre, Sphagnum papillosum, Sphagnum russowii, Sphagnum subnitens, Sphagnum tenellum, Barbilophozia floerkei, Calypogeia fissa, Calypogeia muelleriana, Calypogeia trichomanis, Cephalozia bicuspidata, Diplophyllum albicans, Kurzia pauciflora, Lophozia ventricosa, Mylia anomala, Mylia taylorii, Ordontoschisma sphagni, Ptilidium ciliare, Hypogymnia physodes, Cetraria islandica, Cladonia arbuscula, Cladonia bellidiflora, Cladonia coccifera, Cladonia floerkeana, Cladonia gracilis, Cladonia impexa, Cladonia squamosa, Cladonia tenuis, Cladonia uncialis, Cornicularia aculeata, Cornus suecica, Drosera rotundifolia, Vaccinium vitis-idaea, Pinguicula vulgaris, Narthecium ossifragum, Neottia cordata, Potentilla erecta, Rubus chamaemorus, Galium saxatile, Melanpyrum pratense, Deschampsia flexuosa, Festuca vivipara, Molinia caerulea, Nardus stricta, Blechnum spicant

M1 — Blanket bog, Raised bog

Sphagnum auriculatum bog pool community

Matches 1 species from the description above: Molinia caerulea

Erica tetralix, Myrica gale, Carex limosa, Eriophorum angustifolium, Rhynchospora alba, Rhynchospora fusca, Trichophorum cespitosum, Eleocharis multicaulis, Juncus bulbosus, Sphagnum auriculatum, Sphagnum cuspidatum, Sphagnum fallax, Sphagnum magellanicum, Sphagnum palustre, Sphagnum papillosum, Sphagnum pulchrum, Sphagnum subnitens, Cladopodiella fluitans, Gymnocolea inflata, Ordontoschisma sphagni, Drosera anglica, Drosera intermedia, Drosera rotundifolia, Utricularia intermedia, Utricularia minor, Menyanthes trifoliata, Narthecium ossifragum, Potamogeton polygonifolius, Scheuchzeria palustris, Molinia caerulea

M15 — Blanket bog, Raised bog, Upland wet heath

Scirpus cespitosus-Erica tetralix wet heath

Matches 1 species from the description above: Molinia caerulea

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica cinerea, Erica tetralix, Myrica gale, Vaccinium myrtillus, Carex binervis, Carex demissa, Carex dioica, Carex echinata, Carex nigra, Carex panicea, Carex pilulifera, Carex pulicaris, Eriophorum angustifolium, Eriophorum vaginatum, Schoenus nigricans, Trichophorum cespitosum, Juncus acutiflorus, Juncus articulatus, Juncus bulbosus, Juncus conglomeratus, Juncus effusus, Juncus squarrosus, Luzula multiflora, Huperzia selago, Selaginella selaginoides, Aulacomnium palustre, Breutelia chrysocoma, Pohlia nutans, Campylopus atrovirens, Campylopus flexuosus, Dicranum scoparium, Leucobryum glaucum, Racomitrium lanuginosum, Hylocomium splendens, Hypnum cupressiforme, Hypnum jutlandicum, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Scorpidium revolvens, Scorpidium scorpioides, Polytrichum commune, Sphagnum auriculatum, Sphagnum capillifolium, Sphagnum compactum, Sphagnum fallax, Sphagnum palustre, Sphagnum papillosum, Sphagnum subnitens, Sphagnum tenellum, Calypogeia fissa, Calypogeia muelleriana, Diplophyllum albicans, Lophozia ventricosa, Ordontoschisma sphagni, Pleurozia purpurea, Aneura pinguis, Cladonia arbuscula, Cladonia chlorophaea, Cladonia coccifera, Cladonia impexa, Cladonia uncialis, Succisa pratensis, Drosera anglica, Drosera rotundifolia, Hypericum pulchrum, Triglochin palustre, Pinguicula vulgaris, Menyanthes trifoliata, Narthecium ossifragum, Dactylorhiza maculata, Euphrasia officinalis, Pedicularis palustris, Pedicularis sylvatica, Polygala serpyllifolia, Trientalis europaea, Potentilla erecta, Galium saxatile, Viola palustris, Agrostis canina, Agrostis capillaris, Agrostis stolonifera, Anthoxanthum odoratum, Danthonia decumbens, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Festuca vivipara, Molinia caerulea, Nardus stricta, Blechnum spicant, Pteridium aquilinum

M17 — Blanket bog

Scirpus cespitosus-Eriophorum vaginatum blanket mire

Matches 1 species from the description above: Molinia caerulea

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Erica cinerea, Erica tetralix, Myrica gale, Vaccinium myrtillus, Carex demissa, Carex echinata, Carex nigra, Carex panicea, Eriophorum angustifolium, Eriophorum vaginatum, Rhynchospora alba, Schoenus nigricans, Trichophorum cespitosum, Juncus acutiflorus, Juncus squarrosus, Luzula multiflora, Huperzia selago, Aulacomnium palustre, Breutelia chrysocoma, Pohlia nutans, Campylopus atrovirens, Campylopus flexuosus, Campylopus setifolius, Campylopus shawii, Dicranum scoparium, Leucobryum glaucum, Racomitrium lanuginosum, Hylocomium splendens, Hypnum cupressiforme, Hypnum jutlandicum, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Polytrichum commune, Polytrichum strictum, Sphagnum auriculatum, Sphagnum capillifolium, Sphagnum cuspidatum, Sphagnum imbricatum, Sphagnum magellanicum, Sphagnum palustre, Sphagnum papillosum, Sphagnum strictum, Sphagnum subnitens, Sphagnum tenellum, Calypogeia fissa, Diplophyllum albicans, Kurzia pauciflora, Lophozia ventricosa, Mylia anomala, Mylia taylorii, Ordontoschisma sphagni, Pleurozia purpurea, Ptilidium ciliare, Scapania gracilis, Cladonia arbuscula, Cladonia coccifera, Cladonia impexa, Cladonia uncialis, Cornicularia aculeata, Drosera anglica, Drosera rotundifolia, Vaccinium vitis-idaea, Pinguicula vulgaris, Narthecium ossifragum, Pedicularis sylvatica, Polygala serpyllifolia, Potentilla erecta, Galium saxatile, Agrostis canina, Anthoxanthum odoratum, Deschampsia flexuosa, Festuca ovina, Molinia caerulea, Nardus stricta

M3 — Blanket bog, Raised bog

Eriophorum angustifolium bog pool community

Matches 1 species from the description above: Molinia caerulea

Empetrum nigrum subsp.nigrum, Erica tetralix, Eriophorum angustifolium, Eriophorum vaginatum, Campylopus brevipilus, Drepanocladus fluitans, Polytrichum commune, Sphagnum cuspidatum, Sphagnum fallax, Sphagnum papillosum, Gymnocolea inflata, Ordontoschisma sphagni, Drosera rotundifolia, Agrostis canina, Molinia caerulea

M20 — Blanket bog, Raised bog, Valley mire

Eriophorum vaginatum blanket and raised mire

Empetrum nigrum subsp.nigrum, Calluna vulgaris, Vaccinium myrtillus, Carex bigelowii, Eriophorum angustifolium, Eriophorum vaginatum, Trichophorum cespitosum, Juncus squarrosus, Orthodontium lineare, Pohlia nutans, Campylopus flexuosus, Dicranum scoparium, Drepanocladus fluitans, Hypnum jutlandicum, Plagiothecium undulatum, Pleurozium schreberi, Polytrichum commune, Sphagnum capillifolium, Sphagnum fuscum, Sphagnum papillosum, Barbilophozia floerkei, Calypogeia muelleriana, Calypogeia trichomanis, Cephalozia bicuspidata, Cephaloziella hampeana, Diplophyllum albicans, Gymnocolea inflata, Kurzia pauciflora, Lophozia ventricosa, Mylia taylorii, Ptilidium ciliare, Cetraria islandica, Cladonia arbuscula, Cladonia chlorophaea, Cladonia coccifera, Cladonia floerkeana, Cladonia impexa, Cladonia squamosa, Cladonia uncialis, Cornicularia aculeata, Rubus chamaemorus, Deschampsia flexuosa, Festuca ovina

Insects to look out for

These moths and butterflies are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

SpeciesStatusVia host-plant
Chequered skipper
Carterocephalus palaemon
Endangered Molinia caerulea
Large heath
Coenonympha tullia
Vulnerable Molinia caerulea
Lead belle
Scotopteryx mucronata
Vulnerable Genista anglica
The anomalous
Stilbia anomala
Vulnerable Molinia caerulea
Rosy marsh moth
Coenophila subrosea
Near Threatened Andromeda polifolia
Silver barred
Deltote bankiana
Near Threatened Molinia caerulea

Hostplant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation (Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.