White Island (off St. Martin's)

Site of Special Scientific Interest · 49.9802, -6.2917

Condition (Natural England)

Favourable (9)
UnitFeatureConditionArea (ha)Assessed
SV921178 Favourable 15.6 2023-01-13
SV924174 Favourable 15.6 2023-01-13
SV924177 Favourable 15.6 2023-01-13
SV925176 Favourable 15.6 2023-01-13
SV925177 Favourable 15.6 2023-01-13
SV926170 Favourable 15.6 2023-01-13
SV926175 Favourable 15.6 2023-01-13
SV926176 Favourable 15.6 2023-01-13
SV927175 Favourable 15.6 2023-01-13

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 Feature: Raised Beach · Geological Period: Quaternary · Rock Type: Breccia

Landscape processes: Coastal, Volcanic / Igneous

Birds & fish recorded

Birds

SpeciesSeason
fulmar Breeding
herring gull Breeding
kittiwake Breeding
lesser black-backed gull Breeding

Description

Area, 16.55 ha40.9 ac1,10,000, Description White Island is located off the north west side of St. Martin’s on the northern margins of the Isles of Scilly archipelago. This small uninhabited island is connected to St. Martin’s by a boulder covered, intertidal causeway and is particularly important for the suite of Late Pleistocene deposits in Chad Girt. Maritime heathland, maritime grassland and scrub habitats also occur here whilst the isolated cliffs support small colonies of breeding sea birds. Chad Girt is a site of longstanding importance for Quaternary studies in the Scillies. It shows a sequence of deposits comprising, 1. raised beach; 2, granitic head Porthloo Breccia; 3, soliflucted material containing glacially derived clasts and loess Hell Bay Gravel; 4, head containing erratics Brad and Cheese Breccia. Chad Girt is a classic site providing important lithostratigraphic evidence for interpreting the Late Pleistocene succession in the Isles of Scilly. Thin skeletal soils and extreme exposure have lead to the development of wind pruned “waved” maritime heath dominated by heather Calluna vulgaris, bell heather Erica cinerea and western gorse Ulex gallii together with common bird’s foot trefoil Lotus corniculatus, heath bedstraw Galium saxatile and English stonecrop Sedum anglicum. The more sheltered areas with deeper soils have bracken Pteridium aquilinum, bramble Rubus fruticosus and honeysuckle Lonicera periclymenum. Small areas of short turfed maritime grassland occur along the western coastal margin where thrift Armeria maritima, sea beet Beta vulgaris sp maritima, red fescue Festuca rubra, common scurvy grass Cochlearia officinalis and buck’s horn plantain Plantago coronopus are common. In addition the isolated habitats on White Island support five species of breeding sea birds including lesser black backed gull Larus fuscus, herring gull Larus argentatus, great black backed gull L. marinus, kittiwake Rissa tridactyla and fulmar Fulmarus glacialis. Notified to the Secretary of State on 31 March 1989

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
fulmar Fulmarus glacialis CR (Breeding) bird-fulmar procellariidae
herring gull Larus argentatus EN (NonBreeding), EN (Breeding) bird-gull laridae
lesser black-backed gull Larus fuscus DD (Breeding) bird-gull laridae
kittiwake Rissa tridactyla EN (Breeding) bird-gull laridae
bracken Pteridium aquilinum LC fern dennstaedtiaceae
red fescue Festuca rubra LC grass poaceae
thrift Armeria maritima CR herb plumbaginaceae
sea beet Beta vulgaris sp maritima Not listed in GB list herb chenopodiaceae
scurvy grass Cochlearia officinalis LC herb brassicaceae
heath bedstraw Galium saxatile LC herb rubiaceae
honeysuckle Lonicera periclymenum LC herb caprifoliaceae
birdsfoot trefoil Lotus corniculatus LC herb fabaceae
buck's-horn plantain Plantago coronopus LC herb plantaginaceae
bramble Rubus fruticosus LC herb rosaceae
English stonecrop Sedum anglicum LC herb crassulaceae
western gorse Ulex gallii LC shrub leguminosae
bell heather or ling Calluna vulgaris NT shrub dwarf ericaceae
bell heather Erica cinerea NT shrub dwarf ericaceae

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