Obain Loch Euphoirt

Site of Special Scientific Interest · 57.5627, -7.2187

Open in the interactive map →

Also within

Western Isles County

Condition (NatureScot)

Favourable (2)
UnitFeatureConditionArea (ha)Assessed
F1 Saline lagoon Favourable — 2005-03-31
F2 Foxtail stonewort (Lamprothamnium papulosum) Favourable — 2016-02-02

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

Salt marsh

Geology & landscape

Rock Type: Gneiss

Landscape processes: Coastal, Fluvial, Glacial, Volcanic / Igneous

Description

Obain Loch Euphoirt Obain Loch Euphoirt SSSI comprises three brackish inlets (obain) in the Loch Euphoirt fjardic complex on the south side of North Uist. The site is specifically designated for these brackish obain, which are known as saline lagoons, and the nationally scarce alga foxtail stonewort Lamprothamnion papulosum. The largest, Oban nam Fiadh consists of a series of basin and pools linking the freshwater Loch Carabhat with the west end of Loch Euphoirt. Oban Spònais is a 1km long inlet emptying into Bagh Spònais half-way along the north side of Loch Euphoirt. Bàgh Uaine is a small pool along the south shore of the main loch opposite the island of Steiseigh. The obain occupy hollows which were scoured out of the gneiss by glacial action and later invaded by saltwater when sea levels rose after the Ice Age. The three obain together form an outstanding example of a network of rock-silled saline lagoons, a habitat which is rare in Europe outside the Western Isles and Shetland. They exhibit a wide range of special features which distinguish rock-silled obs from other marine habitats. Oban nam Fiadh possesses a complete range of salinities from freshwater to saltwater, demonstrated by the range of plant communities which extends from reeds Phragmites australis at the far eastern end to seaweeds like bladder wrack Fucus vesiculosus near the entrance to Loch Euphoirt. This range of salinities is sometimes accompanied by the occurrence of a halocline, ie the separation of the water column into an upper layer of brackish or fresh water and a lower layer of saltwater. All three obain have abundant underwater beds of tasselweed Ruppia spp., while the two larger also have extensive areas of eelgrass Zostera marina. Oban nam Fiadh contains the nationally scarce stonewort Lamprothamnion papulosum, which is a designated feature of the site. The site contains several biotopes which are particularly associated with rocky substrates in obain. These include a subtidal assemblage dominated by the wrack Fucus ceranoides and an unusual community of dense Cladophora rupestris on boulders. Oban Spònish also has a good example of one of the most widespread and distinctive biotopes of rock-silled obain. This biotope is dominated by the red alga Furcellaria lumbricalis with a high density of epiphytic sea-squirts and is found on boulder substrates. All the shores within the site also exhibit the compressed intertidal zonation due to reduced tidal range which is characteristic of these obain. The rock or boulder sills which separate the obain from Loch Euphoirt itself are of interest because of their high diversity of small, often filter-feeding, animals. They have a significantly richer fauna than the inner basins: the undersides of boulders and the fronds of seaweeds may be densely colonised by species such as mussels Mytilus edulis, sea-squirts Ciona intestinalis and Ascidiella spp. and various sponges such as Halichondria panicea which thrive in the strong currents of the tidal rapids. The sill complex at the entrance to Oban nam Fiadh is particularly extensive, consisting of at least five separate sills, which are dominated by a variety of fucoid seaweeds. At the seaward ends of the obain, shores tend to show a zonation, starting at the highest point of tidal influence with the tiny seaweed Fucus cottonii in saltmarsh turf. However, these obain are typical in lacking the diversity of shores biotopes that would be found on similar shores in a sea loch. Many shores are simply occupied by a sparse cover of channel wrack Pelvetia canaliculata, which may descend to a zone dominated by either Fucus spiralis or, in more brackish conditions, Fucus ceranoides. The mud-bottomed, sheltered basins found in all three obain are quite species-poor compared to the greater diversity found at the sills, with tasselweed Ruppia and, abundant in Oban Spònais, the opisthobranch mollusc Akera bullata being two species characteristic of these conditions. Oban nam Fiadh differs from the other two obain in containing several plants normally confined to freshwater such as reed Phragmites australis, pondweeds Potamogeton spp. and water lobelia Lobelia dortmanna.

Species mentioned

English name
search for this in other sites		 Latin name
search with Google		 IUCN / Red List Type Family
horned wrack Fucus ceranoides Not listed in GB list algae brown fucaceae
moss wrack Fucus cottonii Not listed in GB list algae brown fucaceae
spiraled wrack Fucus spiralis Not listed in GB list algae brown fucaceae
bladder wrack Fucus vesiculosus Not listed in GB list algae brown fucaceae
channel wrack Pelvetia canaliculata Not listed in GB list algae brown fucaceae
common green branched weeds Cladophora rupestris Not listed in GB list algae green cladophoraceae
foxtail stonewort Lamprothamnion papulosum Not listed in GB list algae green characeae
clawed forkweed Furcellaria lumbricalis Not listed in GB list algae red furcellariaceae
blue mussel Mytilus edulis LC bivalve mytilidae
common reed Phragmites australis LC grass poaceae
water lobelia Lobelia dortmanna LC herb campanulaceae
eelgrass Zostera marina VU herb zosteraceae
breadcomb sponge Halichondria panicea Not listed in GB list sponge halichondriidae

Plant communities

SM1 — Salt marsh

Zostera communities

Zostera angustifolia, Zostera marina, Zostera noltei, Spartina anglica, Porphyra umbilicalis, Chondria dasyphylla, Polysiphonia nigra, Chara aspera, Chaetomorpha linum, Chaetomorpha tortuosa, Cladophora battersii, Cladophora retroflexa, Ulva intestinalis, Ulva lactuca, Fucus spiralis

SM2 — Salt marsh

Ruppia maritima salt-marsh community

Ruppia maritima

SM3 — Salt marsh

Eleocharis parvula salt-marsh community

Eleocharis parvula

SM4 — Salt marsh

Spartina maritima salt-marsh community

Suaeda maritima, Salicornia europaea, Salicornia perennis, Puccinellia maritima, Spartina anglica, Spartina maritima

SM5 — Salt marsh

Spartina alterniflora salt-marsh community

Puccinellia maritima, Spartina alterniflora, Spartina anglica

SM6 — Salt marsh

Spartina anglica salt-marsh community

Atriplex portulacoides, Suaeda maritima, Aster tripolium, Cochlearia anglica, Spergularia media, Atriplex hastata, Salicornia europaea, Plantago maritima, Limonium vulgare, Puccinellia maritima, Spartina anglica, Catenella caespitosa, Fucus vesiculosus, Fucus vesiculosus ecad volubilis

SM7 — Salt marsh

Arthrocnemum perenne stands

Atriplex portulacoides, Suaeda maritima, Aster tripolium, Spergularia media, Salicornia europaea, Salicornia perennis, Limonium vulgare, Puccinellia maritima, Bostrychia scorpioides

SM8 — Salt marsh

Annual Salicornia salt-marsh community

Atriplex portulacoides, Suaeda maritima, Aster tripolium, Salicornia europaea, Puccinellia maritima, Spartina anglica

SM9 — Salt marsh

Suaeda maritima salt-marsh community

Atriplex portulacoides, Suaeda maritima, Aster tripolium, Salicornia europaea, Puccinellia maritima, Spartina anglica

SM10 — Salt marsh

Transitional low-marsh vegetation with Puccinellia maritima annual Salicornia species and Suaeda maritima

Atriplex portulacoides, Suaeda maritima, Aster tripolium, Spergularia media, Salicornia europaea, Triglochin maritimum, Armeria maritima, Limonium vulgare, Puccinellia maritima, Spartina anglica

SM11 — Salt marsh

Aster tripolium var. discoideus salt-marsh community

Atriplex portulacoides, Suaeda maritima, Aster tripolium, Spergularia media, Salicornia europaea, Salicornia perennis, Plantago maritima, Puccinellia maritima, Spartina anglica, Bostrychia scorpioides, Fucus vesiculosus, Pelvetia canaliculata

SM12 — Salt marsh

Rayed Aster Tripolium on slat marshes

Schoenoplectus lacustris, Juncus bufonius, Suaeda maritima, Aster tripolium, Spergularia marina, Spergularia media, Atriplex hastata, Salicornia europaea, Triglochin maritimum, Plantago maritima, Puccinellia distans, Puccinellia maritima, Spartina anglica

SM13 — Salt marsh

Puccinellia maritima salt-marsh community

Atriplex portulacoides, Juncus gerardii, Suaeda maritima, Aster tripolium, Cochlearia anglica, Cochlearia officinalis, Spergularia media, Atriplex hastata, Salicornia europaea, Salicornia perennis, Triglochin maritimum, Plantago maritima, Armeria maritima, Limonium humile, Limonium vulgare, Glaux maritima, Agrostis stolonifera, Festuca rubra, Puccinellia maritima, Spartina anglica, Spartina maritima, Bostrychia scorpioides, Fucus cottonii

SM14 — Salt marsh

Halimione portulacoides salt-marsh community

Atriplex portulacoides, Juncus maritimus, Suaeda maritima, Artemisia maritima, Aster tripolium, Inula crithmoides, Spergularia media, Salicornia europaea, Salicornia perennis, Triglochin maritimum, Plantago maritima, Armeria maritima, Limonium vulgare, Elytrigia atherica, Puccinellia maritima, Spartina anglica

SM15 — Salt marsh

Juncus maritimus-Triglochin maritima salt-marsh community

Atriplex portulacoides, Carex extensa, Juncus gerardii, Juncus maritimus, Suaeda maritima, Oenanthe lachenalii, Artemisia maritima, Cochlearia anglica, Cochlearia officinalis, Spergularia media, Atriplex hastata, Salicornia europaea, Triglochin maritimum, Plantago maritima, Armeria maritima, Limonium humile, Limonium vulgare, Glaux maritima, Agrostis stolonifera, Festuca rubra, Phragmites australis, Puccinellia maritima, Spartina anglica, Fucus cottonii

SM16 — Salt marsh

Festuca rubra salt-marsh community

Atriplex portulacoides, Carex distans, Carex flacca, Juncus gerardii, Hypnum cupressiforme, Kindbergia praelonga, Rhytidiadelphus squarrosus, Scorzoneroides autumnalis, Cochlearia anglica, Cerastium fontanum, Sagina procumbens, Spergularia media, Atriplex hastata, Salicornia europaea, Lotus corniculatus, Trifolium repens, Triglochin maritimum, Plantago lanceolata, Plantago maritima, Armeria maritima, Limonium vulgare, Glaux maritima, Ranunculus acris, Potentilla anserina, Agrostis stolonifera, Anthoxanthum odoratum, Cynosurus cristatus, Festuca rubra, Holcus lanatus, Puccinellia maritima

SM17 — Salt marsh

Artemisia maritima salt-marsh community

Atriplex portulacoides, Juncus gerardii, Juncus maritimus, Suaeda maritima, Suaeda vera, Artemisia maritima, Cochlearia anglica, Cochlearia officinalis, Spergularia media, Atriplex hastata, Salicornia europaea, Triglochin maritimum, Plantago coronopus, Plantago maritima, Armeria maritima, Limonium vulgare, Glaux maritima, Agrostis stolonifera, Elytrigia atherica, Elytrigia repens, Festuca rubra, Hordeum marinum, Parapholis strigosa, Puccinellia maritima

SM18 — Salt marsh

Juncus maritimus salt-marsh community

Carex distans, Carex extensa, Carex otrubae, Juncus gerardii, Juncus maritimus, Amblystegium serpens, Kindbergia praelonga, Oenanthe lachenalii, Cirsium arvense, Scorzoneroides autumnalis, Sonchus arvensis, Cochlearia officinalis, Silene flos-cuculi, Atriplex hastata, Lotus corniculatus, Trifolium repens, Vicia cracca, Triglochin maritimum, Plantago maritima, Armeria maritima, Rumex crispus, Glaux maritima, Samolus valerandi, Ranunculus acris, Potentilla anserina, Galium palustre, Agrostis stolonifera, Elytrigia repens, Festuca rubra, Holcus lanatus, Poa pratensis, Schedonorus arundinaceus

SM19 — Saline lagoon, Salt marsh

Blysmus rufus salt-marsh community

Blysmus rufus, Carex extensa, Carex lepidocarpa, Carex nigra, Eleocharis quinqueflora, Eleocharis uniglumis, Juncus articulatus, Juncus gerardii, Amblystegium serpens, Calliergonell cuspidatum, Drepanocladus polygamus, Leptodictyum riparium, Oenanthe lachenalii, Scorzoneroides autumnalis, Cochlearia anglica, Trifolium repens, Triglochin maritimum, Triglochin palustre, Plantago maritima, Armeria maritima, Glaux maritima, Potentilla anserina, Agrostis stolonifera, Alopecurus geniculatus, Festuca rubra, Puccinellia maritima

SM20 — Saline lagoon, Salt marsh

Eleocharis uniglumis salt-marsh community

Bolboschoenus maritimus, Carex distans, Carex extensa, Carex nigra, Eleocharis quinqueflora, Eleocharis uniglumis, Juncus articulatus, Juncus gerardii, Leptodictyum riparium, Oenanthe lachenalii, Hydrocotyle vulgaris, Scorzoneroides autumnalis, Atriplex hastata, Trifolium repens, Triglochin maritimum, Triglochin palustre, Plantago maritima, Armeria maritima, Glaux maritima, Samolus valerandi, Potentilla anserina, Galium palustre, Agrostis stolonifera, Alopecurus geniculatus, Festuca rubra

SM21 — Salt marsh

Suaeda vera-Limonium binervosum salt-marsh community

Atriplex portulacoides, Frankenia laevis, Suaeda maritima, Suaeda vera, Artemisia maritima, Cochlearia anglica, Cochlearia danica, Cochlearia officinalis, Sagina maritima, Spergularia marina, Spergularia media, Salicornia europaea, Plantago maritima, Armeria maritima, Limonium bellidifolium, Limonium binervosum, Limonium vulgare, Glaux maritima, Elytrigia atherica, Festuca rubra, Puccinellia maritima

SM22 — Salt marsh

Halimione portulacoides-Frankenia laevis salt-marsh community

Atriplex portulacoides, Frankenia laevis, Suaeda maritima, Spergularia media, Salicornia europaea, Salicornia perennis, Plantago coronopus, Plantago maritima, Armeria maritima, Limonium vulgare, Elytrigia juncea, Festuca rubra, Parapholis strigosa, Puccinellia maritima

SM23 — Salt marsh

Spergularia marina-Puccinellia distans salt-marsh community

Atriplex portulacoides, Juncus bufonius, Suaeda maritima, Spergularia marina, Spergularia media, Atriplex hastata, Salicornia europaea, Triglochin maritimum, Plantago maritima, Polygonum aviculare, Glaux maritima, Agrostis stolonifera, Alopecurus geniculatus, Elytrigia atherica, Festuca rubra, Parapholis strigosa, Puccinellia distans, Puccinellia maritima

SM24 — Salt marsh

Elymus pycnanthus salt-marsh community

Atriplex portulacoides, Juncus gerardii, Juncus maritimus, Hypnum cupressiforme, Suaeda vera, Artemisia maritima, Aster tripolium, Sonchus arvensis, Atriplex hastata, Atriplex littoralis, Beta vulgaris sp maritima, Plantago maritima, Armeria maritima, Limonium vulgare, Glaux maritima, Potentilla anserina, Galium aparine, Agrostis stolonifera, Ammophila arenaria, Elytrigia atherica, Festuca rubra, Parapholis strigosa, Phragmites australis, Puccinellia maritima

SM25 — Salt marsh

Suaeda vera drift-line community

Atriplex portulacoides, Suaeda maritima, Suaeda vera, Artemisia maritima, Cochlearia anglica, Cochlearia danica, Cochlearia officinalis, Spergularia media, Atriplex littoralis, Salicornia europaea, Salicornia perennis, Triglochin maritimum, Plantago maritima, Limonium vulgare, Glaux maritima, Elytrigia atherica, Festuca rubra, Puccinellia maritima, Bostrychia scorpioides, Pelvetia canaliculata

SM26 — Salt marsh

Inula crithmoides stands

Atriplex portulacoides, Suaeda maritima, Inula crithmoides, Spergularia media, Salicornia europaea, Salicornia perennis, Plantago maritima, Armeria maritima, Limonium vulgare, Elytrigia atherica, Festuca rubra, Puccinellia maritima, Spartina anglica, Bostrychia scorpioides

SM28 — Salt marsh

Elymus repens salt-marsh community

Bolboschoenus maritimus, Carex otrubae, Eleocharis uniglumis, Juncus gerardii, Kindbergia praelonga, Odontites verna, Anthriscus sylvestris, Apium graveolens, Heracleum sphondylium, Oenanthe crocata, Oenanthe lachenalii, Torilis japonica, Centaurea nigra, Cirsium arvense, Cirsium vulgare, Scorzoneroides autumnalis, Sonchus arvensis, Tripleurospermum maritimum, Cochlearia anglica, Cochlearia officinalis, Silene uniflora, Stellaria media agg., Atriplex hastata, Atriplex littoralis, Calystegia sepium, Lotus corniculatus, Medicago lupulina, Melilotus altissima, Trifolium repens, Vicia cracca, Triglochin maritimum, Plantago lanceolata, Plantago maritima, Rumex conglomeratus, Rumex crispus, Glaux maritima, Potentilla anserina, Galium aparine, Urtica dioica, Agrostis stolonifera, Alopecurus geniculatus, Arrhenatherum elatius, Dactylis glomerata, Deschampsia cespitosa, Elytrigia repens, Festuca rubra, Holcus lanatus, Lolium perenne, Poa pratensis, Puccinellia maritima, Schedonorus arundinaceus