Keen of Hamar

Site of Special Scientific Interest · 60.7679, -0.8200

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Also within

Shetland County

Condition (NatureScot)

Favourable (2) Unfavourable Recovering (1)
UnitFeatureConditionArea (ha)Assessed
F1 Mineralogy of Scotland Favourable — 2005-03-31
F2 Calaminarian grassland and serpentine heath Favourable — 2014-08-01
F3 Vascular plant assemblage Unfavourable Recovering — 2014-11-17

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.

Habitats

Calaminarian grassland, Lizard peninsula

Geology & landscape

Mining / Industrial: Calaminarian, Quarry · Rock Type: Glacial Till

Landscape processes: Coastal, Glacial

Description

KEEN OF HAMAR Keen of Hamar SSSI is located to the north-east of Baltasound on the east coast of Unst, the most northerly island of Shetland. It comprises the fenced lower Keen and upper Keen (western and eastern compartments respectively) separated by the ‘cattle corridor’, Hagdale chromite quarry and the coastline from Geo of Hagdale to Muckle Geo of the Keen. The site is notified for its geological interest: chromite mineralisation (ferrous chromate, FeCr2O4) is present at Hagdale quarry and the Wick of Hagdale, and for the serpentine soils of the Keen of Hamar which support a patchwork of calaminarian grassland (vegetation growing on soils containing heavy metals) with associated plant rarities and species-rich serpentine heath. Hagdale quarry was the largest chromite working in Britain, and although the quarry itself is now infilled, excellent samples of chromite ore and vein serpentine are present on the spoil dumps. The chromite mineralisation occurs as lenses within the serpentine host rock. Other minerals of interest associated with chromite are found including nickel hydroxides. In the Wick of Hagdale, chromite bands up to 5 cm thick and clots of chromite crystals up to 1 cm in diameter are present within the serpentine. Along two series of shear zones, well-developed fibrous and columnar varieties of the serpentine mineral antigorite (a magnesium hydroxysilicate) occur, as well as green resinous ‘precious’ serpentine. The site contains one of the finest examples of serpentine debris vegetation in Europe and supports a number of national plant rarities. It provides an interesting contrast to the other major serpentine outcrops in Britain such as the Lizard Peninsula in Cornwall and those in North-East Scotland. The unique flora is related directly to the unusual chromite-serpentine substrate and the soils derived from this, which are deficient in phosphorous, nitrogen and potassium but contain high levels of heavy metals such as chromium, magnesium and nickel. The principal vegetation types are a sparse fell-field community on bare serpentine debris and a closed sward of short heather and grasses on soil derived from glacial till. The debris vegetation holds an unusual mixture of montane and maritime species and uncommon forms of some of these are present. Species including nationally rare Scottish sandwort Arenaria norvegica ssp. norvegica and Shetland mouse-ear Cerastium nigrescens -endemic to this site and nearby Nikka Vord -and nationally scarce northern rock-cress Arabidopsis petraea are found.

Species mentioned

English name
search for this in other sites		 Latin name
search with Google		 IUCN / Red List Type Family
northern rock cress Arabidopsis petraea LC herb brassicaceae
arctic sandwort Arenaria norvegica EN herb carophyllaceae
artic mouse ear Cerastium nigrescens NT herb carophyllaceae

Plant communities

H6 — Lizard peninsula, Lowland heath

Erica vagans-Ulex europaeus heath

Calluna vulgaris, Erica cinerea, Erica tetralix, Erica vagans, Ulex europaeus, Ulex gallii, Prunus spinosa, Carex caryophyllea, Carex flacca, Carex panicea, Carex pulicaris, Schoenus nigricans, Campylopus flexuosus, Dicranum scoparium, Hypnum cupressiforme, Hypnum jutlandicum, Trichostomum brachydontium, Cladonia fimbriata, Cladonia furcata, Cladonia impexa, Daucus carota, Pimpinella saxifraga, Hypochaeris radicata, Leontodon saxatilis, Leucanthemum vulgare, Serratula tinctoria, Solidago virgaurea, Jasione montana, Anthyllis vulneraria, Lotus corniculatus, Centaurium erythraea, Geranium sanguineum, Hypericum humifusum, Hypericum pulchrum, Teucrium scorodonia, Thymus praecox, Scilla verna, Pedicularis sylvatica, Plantago lanceolata, Plantago maritima, Polygala serpyllifolia, Polygala vulgaris, Filipendula vulgaris, Potentilla erecta, Rubus fruticosus agg., Sanguisorba officinalis, Galium verum, Viola lactea, Viola riviniana, Agrostis capillaris, Agrostis curtisii, Agrostis vinealis, Aira caryophyllea, Anthoxanthum odoratum, Brachypodium sylvaticum, Dactylis glomerata, Danthonia decumbens, Festuca ovina, Festuca rubra, Holcus lanatus, Koeleria macrantha, Molinia caerulea, Pteridium aquilinum, Chara curta

OV37 — Calaminarian grassland

Festuca ovina-Minuartia verna community

Calluna vulgaris, Carex caryophyllea, Carex flacca, Bryum pallens, Pohlia nutans, Dicranum scoparium, Rhytidiadelphus squarrosus, Weissia controversa, Cladonia arbuscula, Cladonia chlorophaea, Cladonia furcata, Cladonia gracilis, Cladonia portentosa, Cladonia pyxidata, Cladonia rangiformis, Coelocaulon aculeatum, Parmelia saxatilis, Achillea millefolium, Cirsium vulgare, Jacobaea vulgaris, Pilosella officinarum, Noccaea caerulescens, Campanula rotundifolia, Cerastium fontanum, Minuartia verna, Anthyllis vulneraria, Lotus corniculatus, Trifolium repens, Geranium robertianum, Thymus praecox, Linum catharticum, Euphrasia officinalis, Plantago lanceolata, Rumex acetosa, Galium saxatile, Galium sterneri, Viola lutea, Agrostis capillaris, Agrostis stolonifera, Anthoxanthum odoratum, Arrhenatherum elatius, Avenula pratensis, Dactylis glomerata, Festuca ovina, Festuca rubra, Koeleria macrantha