Blackdown (Hardy Monument)

Site of Special Scientific Interest · 50.6858, -2.5499

Condition (Natural England)

Favourable (3) Unfavourable Recovering (1)
UnitFeatureConditionArea (ha)Assessed
SY611877 Favourable 9.46 2011-09-30
SY612875 Favourable 8.97 2011-09-30
SY613874 Unfavourable Recovering 2.3 2011-09-30
SY613875 Favourable 1.11 2011-10-20

Geology & landscape

Geological Period: Paleogene

Landscape processes: Fluvial

Description

Blackdown (Hardy’s Monument) SSSI Description Blackdown is situated at an altitude of about 200 metres near the western limit of the Bagshot Beds. It is an extremely important geological site and the plant communities which have developed on the acid podzolic soils give the area additional biological interest. This is a key locality for study of the Tertiary Period of geological time in Britain, between 35 and 55 million years ago. The importance of the site is twofold. Firstly, the rocks within the site provide evidence of a type of sedimentation unique in rocks of this age in southern England, namely sedimentation in a powerful alluvial river system, with features suggesting sediment deposition in a “braided river” environment – a network of continually-changing river channels. Secondly, the pebbles and rock fragments which comprise the gravels provide important information on the history of development of this part of southern England at this time, and an analysis of their composition and source enables geologists to determine the evolution of the region. In particular, it provides evidence that some movement along the Ridgeway Fault took place in Eocene times. Parts of the site are dominated by mature ling Calluna vulgaris with bell heather Erica cinerea, the mosses: red stemmed feather moss Pleurozium schreberi, heath plait moss Hypnum jutlandicum, broom fork moss Dicranum scoparium and heath star moss Campylopus introflexus and several lichens of the genus Cladonia including C. portentosa, C. rangiformis, C. coccifera, C. floekiana and C. crispata. Bilberry Vaccinium myrtillus, a local plant in Dorset, is scattered and in places forms dense patches. Bracken Pteridium aquilinum which dominates other areas is locally associated with broad buckler fern Dryopteris dilatata, bramble Rubus fruticosus, wood sage Teucrium scorodonia, wavy hair-grass Deschampsia flexuosa, bristle bent Agrostis curtisii and in damper areas, purple moor-grass Molinia caerulea. Western gorse Ulex gallii is the dominant scrub species but common gorse Ulex europaeus also occurs and there are several hawthorn Crataegus monogyna, including some sizeable old specimens which support abundant epiphytic mosses and lichens. One part of the site was badly burned in 1976 and has suffered considerable erosion, whilst regenerating ling, currently supports a plant community with a high content of wavy hair-grass and the mosses juniper hair cap Polytrichum juniperinum and bristly hair cap Polytrichum piliferum.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
broad buckler fern Dryopteris dilatata LC fern dryopteridaceae
bracken Pteridium aquilinum LC fern dennstaedtiaceae
bristle bent Agrostis curtisii LC grass poaceae
wavy hair grass Deschampsia flexuosa Not listed in GB list grass poaceae
purple moor grass Molinia caerulea LC grass poaceae
bramble Rubus fruticosus LC herb rosaceae
wood sage Teucrium scorodonia LC herb lamiaceae
heath star moss Campylopus introflexus NA moss dicranales
broom fork moss Dicranum scoparium LC moss dicranales
heath plait moss Hypnum jutlandicum LC moss hypnales
red stemmed feather moss Pleurozium schreberi LC moss hypnales
juniper hair cap Polytrichum juniperinum LC moss polytrichales
bristly hair cap Polytrichum piliferum LC moss polytrichales
hawthorn Crataegus monogyna LC shrub rosaceae
gorse Ulex europaeus LC shrub leguminosae
western gorse Ulex gallii LC shrub leguminosae
billberry Vaccinium myrtillus LC shrub ericaceae
bell heather or ling Calluna vulgaris NT shrub dwarf ericaceae
bell heather Erica cinerea NT shrub dwarf ericaceae

Insects to look out for

These moths, butterflies and beetles 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
Speckled footman
Coscinia cribraria
Critically Endangered Agrostis curtisii, Vaccinium myrtillus
Chequered skipper
Carterocephalus palaemon
Endangered Molinia caerulea
Figure of eight
Diloba caeruleocephala
Endangered Crataegus spp.
The lappet
Gastropacha quercifolia
Endangered Crataegus monogyna
Shoulder-striped clover
Heliothis maritima
Endangered Calluna vulgaris, Erica cinerea
Heath fritillary
Melitaea athalia
Endangered Teucrium scorodonia
Scarce vapourer
Orgyia recens
Endangered Crataegus spp., Rubus fruticosus
Mouse moth
Amphipyra tragopoginis
Vulnerable Crataegus spp.
The sprawler
Asteroscopus sphinx
Vulnerable Crataegus spp.
Broom moth
Ceramica pisi
Vulnerable Calluna vulgaris, Pteridium aquilinum, Rubus fruticosus, Vaccinium myrtillus
Large heath
Coenonympha tullia
Vulnerable Molinia caerulea
Mottled umber
Erannis defoliaria
Vulnerable Crataegus spp., Vaccinium myrtillus
Satyr pug
Eupithecia satyrata
Vulnerable Calluna vulgaris
Grayling
Hipparchia semele
Vulnerable Agrostis curtisii
True lover's knot
Lycophotia porphyrea
Vulnerable Calluna vulgaris, Erica cinerea
The lackey
Malacosoma neustria
Vulnerable Crataegus monogyna, Rubus fruticosus
Pale brindled
Phigalia pilosaria
Vulnerable Crataegus monogyna
Silver studded blue
Plebejus argus
Vulnerable Calluna vulgaris, Erica cinerea, Ulex spp.
Grizzled skipper
Pyrgus malvae
Vulnerable Rubus fruticosus
Lead belle
Scotopteryx mucronata
Vulnerable Ulex europaeus
The anomalous
Stilbia anomala
Vulnerable Molinia caerulea
Early moth
Theria primaria
Vulnerable Crataegus monogyna, Vaccinium myrtillus
Pale eggar
Trichiura crataegi
Vulnerable Calluna vulgaris, Crataegus monogyna, Erica cinerea, Rubus fruticosus, Vaccinium myrtillus
Flounced chestnut
Agrochola helvola
Near Threatened Calluna vulgaris, Crataegus monogyna, Vaccinium myrtillus
Beaded chestnut
Agrochola lychnidis
Near Threatened Crataegus monogyna, Vaccinium myrtillus
Grey chi
Antitype chi
Near Threatened Crataegus monogyna
Garden tiger
Arctia caja
Near Threatened Pteridium aquilinum
Small heath
Coenonympha pamphilus
Near Threatened Agrostis spp.
Rosy marsh moth
Coenophila subrosea
Near Threatened Vaccinium myrtillus
Silver barred
Deltote bankiana
Near Threatened Molinia caerulea
Grey scalloped
Dyscia fagaria
Near Threatened Calluna vulgaris, Erica cinerea
Large thorn
Ennomos autumnaria
Near Threatened Crataegus spp.
The Silurian
Eriopygodes imbecilla
Near Threatened Vaccinium myrtillus
Autumnal rustic
Eugnorisma glareosa
Near Threatened Calluna vulgaris, Erica cinerea
Grey pug
Eupithecia subfuscata
Near Threatened Crataegus monogyna
Double dart
Graphiphora augur
Near Threatened Crataegus spp.
Weaver's wave
Idaea contiguaria
Near Threatened Calluna vulgaris
Wall
Lasiommata megera
Near Threatened Agrostis spp.
Scotch burnet
Zygaena exulans
Near Threatened Vaccinium myrtillus

Host-plant 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; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.

Plant communities

W20 — Montane scrub

Salix lapponum-Luzula sylvatica scrub

Matches 6 species from the description above: Calluna vulgaris, Deschampsia flexuosa, Dicranum scoparium, Dryopteris dilatata, Pleurozium schreberi, Vaccinium myrtillus

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

W25 — Bracken scrub

Pteridium aquilinum-Rubus fruticosus underscrub

Matches 5 species from the description above: Crataegus monogyna, Dryopteris dilatata, Pteridium aquilinum, Teucrium scorodonia, Ulex europaeus

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

W21 — Hedgerow scrub, Mixed scrub

Crataegus monogyna-Hedera helix scrub

Matches 3 species from the description above: Crataegus monogyna, Pteridium aquilinum, Teucrium scorodonia

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

Matches 3 species from the description above: Pteridium aquilinum, Teucrium scorodonia, Ulex europaeus

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

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

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