Nicodemus Heights
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Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| SY695733 | — | Favourable | 2.17 | 2010-06-09 |
| SY696732 | — | Unfavourable Declining | 0.87 | 2009-06-11 |
| SY697730 | — | Favourable | 4.75 | 2009-09-06 |
Habitats
Geology & landscape
Mining / Industrial: Quarry · Rock Type: Limestone, Tufa
Landscape processes: Karst
Description
Nicodemus Heights SSSI Description Nicodemus Heights forms part of a complex range of habitats including limestone grasslands, cliffs and quarries found on the Isle of Portland. The limestone geology, southern maritime position and land use history give the Island a unique ecological character and rich biodiversity and make Portland one of the key limestone areas in Britain. Nicodemus Heights lies in the north-eastern part of the Island. The southern part of the site has been disturbed by past quarrying activity and the plant communities are the result of natural recolonisation of the calcareous substrates. In the north grassland has developed on thin soils over upper Portland beds. The site is important for limestone grassland communities; for Nationally Rare and Scarce bryophytes and higher plants; for the endemic plant early gentian Gentianella anglica*; and for the Nationally Scarce butterfly silver-studded blue Plebejus argus cretaceus. The unimproved limestone grassland is of high quality and two distinct communities are present. The most extensive type is characterised by abundant upright brome Bromopsis erecta, and also contains frequent or abundant sheep’s fescue Festuca ovina, kidney vetch Anthyllis vulneraria, bird’s foot trefoil Lotus corniculatus, black medick Medicago lupulina and wild carrot Daucus carota. Horseshoe vetch Hippocrepis comosa is locally frequent, and the Nationally Scarce slender tare Vicia parviflora is also present. The second type of unimproved grassland, which has a very restricted distribution nationally, occurs on thin and well-drained soils which have developed over old limestone spoil heaps. This vegetation is short and open with areas of bare rock, and amongst the abundant sheep’s fescue there is frequent squinancywort Asperula cynanchica, wild thyme Thymus polytrichus and mouse-ear hawkweed Pilosella officinarum. The Nationally Scarce dwarf mouse-ear Cerastium pumilum also occurs here, together with a variety of small bryophytes, including two Nationally Rare liverworts Cephaloziella baumgartneri and green blackwort Southbya nigrella, and a Nationally Scarce moss Luisier’s tufa moss Gymnostomum viridulum. These grasslands also support substantial colonies of the endemic and Nationally Scarce plant early gentian Gentianella anglica*. Numbers of plants vary greatly from year to year but the site has recently held over 50% of the total early gentian population on Portland. Small areas of scrub occur within the site, often associated with hollows, boulders and rocks left behind by historic quarrying activity. Ivy Hedera helix growing here provides a host for the Nationally Scarce parasitic plant ivy broomrape Orobanche hederae. Wild privet Ligustrum vulgare and traveller’s joy Clematis vitalba are frequent in these areas, which also contain occasional introduced species such as fig Ficus carica and reflexed stonecrop Sedum rupestre. In the southern part of the site is an area of open vegetation on a stony substrate which contains a variety of plants associated with unimproved calcareous conditions, including marjoram Origanum vulgare and wild parsnip Pastinaca sativa. This part of the site forms the core of a large population of the Nationally Scarce butterfly silver-studded blue Plebejus argus cretaceus. This butterfly has suffered population declines throughout its range and the cretaceus race is now confined to Portland. Nicodemus Heights SSSI supports one of the three largest colonies on Portland. The site also supports a large population of small blue Cupido minimus, a declining butterfly for which Portland is a stronghold. *Species listed on Annex II to Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Flora, and on Schedule 8 of the Wildlife and Countryside Act 1981.
Species mentioned
Show the 24 species mentioned in the description, with red-list statusPlant communities
W20 — Montane scrub
Salix lapponum-Luzula sylvatica scrub
Show 107 indicator speciesSalix 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
Show 81 indicator speciesHedera 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
Show 49 indicator speciesHedera 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