Shimna River

Site of Special Scientific Interest · 54.2153, -5.9648

Open in the interactive map →

Also within

Down County Mourne Scenic Area

Habitats

Fast flowing river and stream, High montane heath and snow bed

Geology & landscape

Landscape processes: Fluvial

Birds & fish recorded

Fish

SpeciesSeason
Atlantic salmon Spawning
European eel Spawning
Sea trout Spawning

Description

Shimna River River The area, which includes the Shimna River and one of its main tributaries the Trassey River, is of special scientific interest because of the physical features of the river and its associated riverine flora and fauna. The Shimna River rises on the slopes of Ott Mountain and flows into the Irish Sea at Newcastle. It is one of the best examples in Northern Ireland of an upland, oligotrophic base-poor river. Apart from the presence of Fofanny Dam, the river is in a highly natural state due to limited human impact. It is of particular note for the naturalness of the river channel, which exhibits all the physical attributes of in-channel features, flow and riverbed types typical of unaltered upland rivers. A short, fast flowing spate river, the Shimna River is characterised by sequences of riffles, runs and pools where its gradient is shallow and the river beds are composed of cobbles, with scattered boulders and sandy margins but where the gradient is steep and the bed composed of bedrock and boulder the flow is more dramatic with rapids, cascades and water falls. The aquatic plants reflect the nutrient-poor and highly acidic character of the water and are dominated by mosses and liverworts. In the upper reaches the Shimna River and its tributary the Trassey River compressed flapwort Nardia compressa and filamentous green algae dominate the channel, with water earwort Scapania undulata, flagellate feather moss Hyocomium armoricum and bulbous rush Juncus bulbosus appearing in the channel further down stream. As the Trassey meets the Shimna there is a marked increase in diversity but again mosses and liverworts predominate. Here, and as far down river as the outskirts of Newcastle, long beaked water feather moss Rhyncostegium riparioides, Alpine water moss Fontinalis squamosa, greater water moss Fontinalis antipyretic and claw brook moss Hygrohypnum ochraceum dominate the channel, and rusty feather moss Brachythecium plumosum, fox tail feather moss Thamnobryum alopecurum, yellow fringe moss Racomitrium aciculare and the liverwort overleaf pellia Pellia epiphylla dominate the boulder tops and wet margins. Another very common bank side moss along the bottom half is the rare Holt's mouse-tail moss Isothecium holtii for which there are only two other records for Northern Ireland, while at the junction of the Shimna and Trassy Rivers Portuguese feather moss Rhynchostegium alopecuroides can be found at its only known location in Northern Ireland. The Shimna River provides excellent habitat for spawning salmonids, with populations of Atlantic salmon Salmo salar, brown trout Salmo trutta and sea trout Salmo trutta present. Other species inhabiting the system include minnow Phoxinus phoxinus, stone loach Barbatula barbatula, 3-spined stickleback Gasterosteus aculeatus and eel Anguilla anguilla. Marginal semi-natural vegetation along the Shimna River is limited, except at its headwater, and is generally confined to a narrow belt of woodland. This woodland is mainly confined to the riverbank and adjacent slopes. The woodland is generally acidic calcifugous in type with a variable structure and composition. Some of the commoner trees and shrubs include downy birch Betula pubescens, hazel Corylus avellana, goat willow Salix caprea and hawthorn Crataegus monogyna. However, in a few locations, impressive mature sessile oak Quercus petraea line the river. The field layer is a mixture of bramble Rubus fruticosus agg. and ferns while the ground cover supports carpets of bluebell Hyacinthoides non-scripta, wood anemone Anemone nemorosa and greater wood rush Luzula sylvatica. https://www.daera-ni.gov.uk/publications/shimna-river-assi

Species mentioned

English name
search for this in other sites		 Latin name
search with Google		 IUCN / Red List Type Family
eel Anguilla anguilla CR fish anguillidae
stone loach Barbatula barbatula LC fish nemacheilidae
three spined stickleback Gasterosteus aculeatus LC fish gasterosteidae
minnow Phoxinus phoxinus LC fish cyprinidae
Atlantic salmon Salmo salar EN fish salmonidae
brown trout Salmo trutta LC fish salmonidae
wood anemone Anemone nemorosa LC herb ranunculaceae
bluebell Hyacinthoides non-scripta LC herb liliaceae
bramble Rubus fruticosus agg. Not listed in GB list herb rosaceae
compressed flapwort Nardia compressa LC liverwort jungermanniales
overleaf pellia Pellia epiphylla LC liverwort metzgeriales
water earwort Scapania undulata LC liverwort jungermanniales
rusty feathermoss Brachythecium plumosum Not listed in GB list moss hypnales
Alpine water moss Fontinalis squamosa LC moss hypnales
claw brook moss Hygrohypnum ochraceum Not listed in GB list moss hypnales
flagellate feather moss Hyocomium armoricum LC moss hypnales
Holt's mouse-tail moss Isothecium holtii LC moss hypnales
yellow fringe moss Racomitrium aciculare LC moss grimmiales
moss Rhynchostegium alopecuroides LC moss brachytheciaceae
long beaked water feather moss Rhyncostegium riparioides Not listed in GB list moss brachytheciaceae
fox tail feather moss Thamnobryum alopecurum LC moss hypnales
bulbous rush Juncus bulbosus LC rush juncaceae
great wood rush Luzula sylvatica LC rush juncaceae
hawthorn Crataegus monogyna LC shrub rosaceae
downy birch Betula pubescens LC tree betulaceae
hazel Corylus avellana LC tree corylaceae
sessile or durmast oak Quercus petraea LC tree fagaceae
goat willow Salix caprea LC tree shrub salicaceae

Plant communities

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

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

CG12 — Alpine and subalpine calcareous grassland, High montane heath and snow bed

Festuca ovina-Alchemilla alpina-Silene acaulis dwarf-herb community

Empetrum nigrum, Calluna vulgaris, Kalmia procumbens, Vaccinium myrtillus, Salix herbacea, Carex bigelowii, Carex demissa, Carex panicea, Carex pilulifera, Carex pulicaris, Juncus trifidus, Juncus triglumis, Luzula campestris, Luzula multiflora, Luzula spicata, Luzula sylvatica, Diphasiastrum alpinum, Huperzia selago, Selaginella selaginoides, Andreaea alpina, Aulacomnium turgidum, Bartramia ithyphylla, Breutelia chrysocoma, Mnium hornum, Dicranum scoparium, Ditrichum flexicaule, Racomitrium canescens sens.lat., Racomitrium fasciculare, Racomitrium lanuginosum, Ctenidium molluscum, Hylocomium splendens, Hypnum callichroum, Hypnum cupressiforme, Hypnum hamulosum, Lescuraea incurvata, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sanionia uncinata, Thuidium delicatulum, Thuidium tamariscinum, Pogonatum urnigerum, Polytrichastrum alpinum, Tortella tortuosa, Barbilophozia hatcheri, Barbilophozia lycopodioides, Diplophyllum albicans, Frullania tamarisci, Nardia scalaris, Plagiochila asplenioides, Ptilidium ciliare, Scapania subalpina, Tritomaria quinquedentata, Cetraria islandica, Cladonia arbuscula, Cladonia gracilis, Cladonia pyxidata, Cladonia uncialis, Peltigera canina, Achillea millefolium, Antennaria dioica, Gnaphalium supinum, Hieraclium spp., Scorzoneroides autumnalis, Solidago virgaurea, Taraxacum officianalis, Myosotis alpestris, Cardamine pratensis, Draba norvegica, Campanula rotundifolia, Succisa pratensis, Cerastium alpinum, Cerastium fontanum, Minuartia sedoides, Sagina saginoides, Silene acaulis, Sedum rosea, Vaccinium vitis-idaea, Thymus praecox, Linum catharticum, Epilobium anagallidifolium, Euphrasia frigida, Euphrasia officinalis, Oxalis acetosella, Plantago maritima, Veronica alpina, Veronica officinalis, Veronica serpyllifolia, Armeria maritima, Polygonum viviparum, Rumex acetosa, Anemone nemorosa, Ranunculus acris, Thalictrum alpinum, Trollius europaeus, Alchemilla alpina, Alchemilla filicaulis, Filipendula ulmaria, Geum rivale, Potentilla crantzii, Potentilla erecta, Sibbaldia procumbens, Galium boreale, Galium saxatile, Saxifraga aizoides, Saxifraga hypnoides, Saxifraga nivalis, Saxifraga oppositifolia, Saxifraga stellaris, Viola lutea, Viola palustris, Viola riviniana, Agrostis canina, Agrostis capillaris, Anthoxanthum odoratum, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Festuca vivipara, Nardus stricta, Poa pratensis, Botrychium lunaria

U7 — High montane heath and snow bed

Nardus stricta-Carex bigelowii grass-heath

Empetrum nigrum, Calluna vulgaris, Vaccinium myrtillus, Vaccinium uliginosum, Salix herbacea, Carex bigelowii, Carex nigra, Carex panicea, Carex pilulifera, Eriophorum vaginatum, Trichophorum cespitosum, Juncus squarrosus, Juncus trifidus, Luzula multiflora, Luzula sylvatica, Diphasiastrum alpinum, Huperzia selago, Campylopus flexuosus, Dicranum fuscescens, Dicranum scoparium, Kiaeria starkei, Racomitrium lanuginosum, Hylocomium splendens, Hypnum cupressiforme, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Polytrichastrum alpinum, Polytrichum commune, Polytrichum juniperinum, Polytrichum piliferum, Polytrichum strictum, Sphagnum capillifolium, Anastrepta orcadensis, Anastrophyllum donianum, Barbilophozia floerkei, Barbilophozia hatcheri, Bazzania tricrenata, Diplophyllum albicans, Lophozia sudetica, Pleurozia purpurea, Ptilidium ciliare, Scapania gracilis, Scapania nemorea, Cetraria delisei, Cetraria islandica, Cladonia arbuscula, Cladonia bellidiflora, Cladonia coccifera, Cladonia gracilis, Cladonia impexa, Cladonia leucophaea, Cladonia pyxidata, Cladonia rangiferina, Cladonia tenuis, Cladonia uncialis, Gnaphalium supinum, Solidago virgaurea, Cornus suecica, Vaccinium vitis-idaea, Thymus praecox, Narthecium ossifragum, Rumex acetosa, Alchemilla alpina, Potentilla erecta, Galium saxatile, Viola palustris, Agrostis capillaris, Agrostis vinealis, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Nardus stricta

U8 — High montane heath and snow bed

Carex bigelowii-Polytrichum alpinum sedge-heath

Vaccinium myrtillus, Salix herbacea, Carex bigelowii, Juncus trifidus, Luzula spicata, Huperzia selago, Pohlia nutans, Dicranum fuscescens, Dicranum scoparium, Racomitrium canescens sens.lat., Racomitrium fasciculare, Racomitrium lanuginosum, Hylocomium splendens, Pleurozium schreberi, Sanionia uncinata, Polytrichastrum alpinum, Sphagnum compactum, Ptilidium ciliare, Cetraria delisei, Cetraria islandica, Cladonia arbuscula, Cladonia bellidiflora, Cladonia coccifera, Cladonia floerkeana, Cladonia gracilis, Cladonia macrophylla, Cladonia pyxidata, Cladonia rangiferina, Cladonia squamosa, Cladonia uncialis, Cornicularia aculeata, Ochrolechia frigida, Galium saxatile, Saxifraga stellaris, Agrostis capillaris, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Nardus stricta

U9 — High montane heath and snow bed

Juncus trifidus-Racomitrium lanuginosum rush-heath

Empetrum nigrum, Kalmia procumbens, Vaccinium myrtillus, Vaccinium uliginosum, Salix herbacea, Carex bigelowii, Carex pilulifera, Juncus trifidus, Luzula spicata, Diphasiastrum alpinum, Huperzia selago, Dicranum fuscescens, Racomitrium lanuginosum, Pleurozium schreberi, Polytrichastrum alpinum, Polytrichum piliferum, Barbilophozia floerkei, Diplophyllum albicans, Ptilidium ciliare, Cetraria delisei, Cetraria islandica, Cetraria nivalis, Cladonia arbuscula, Cladonia bellidiflora, Cladonia coccifera, Cladonia crispata, Cladonia gracilis, Cladonia pyxidata, Cladonia rangiferina, Cladonia uncialis, Cornicularia aculeata, Ochrolechia frigida, Sphaerophorus globosus, Stereocaulon vesuvianum, Thamnolia vermicularis, Silene acaulis, Vaccinium vitis-idaea, Armeria maritima, Polygonum viviparum, Alchemilla alpina, Galium saxatile, Agrostis capillaris, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Nardus stricta, Nitella flexilis

U10 — High montane heath and snow bed, Lowland dry acid grassland, Upland dry heath

Carex bigelowii-Racomitrium lanuginosum moss-heath

Empetrum nigrum, Kalmia procumbens, Vaccinium myrtillus, Salix herbacea, Carex bigelowii, Carex panicea, Carex pilulifera, Juncus squarrosus, Juncus trifidus, Luzula spicata, Diphasiastrum alpinum, Huperzia selago, Selaginella selaginoides, Andreaea alpina, Aulacomnium turgidum, Pohlia nutans, Campylopus flexuosus, Dicranum fuscescens, Dicranum scoparium, Kiaeria starkei, Racomitrium fasciculare, Racomitrium heterostichum, Racomitrium lanuginosum, Hylocomium splendens, Hypnum callichroum, Hypnum cupressiforme, Hypnum hamulosum, Pleurozium schreberi, Rhytidiadelphus loreus, Sanionia uncinata, Polytrichastrum alpinum, Polytrichum juniperinum, Polytrichum longisetum, Polytrichum piliferum, Polytrichum strictum, Anastrepta orcadensis, Diplophyllum albicans, Nardia scalaris, Ptilidium ciliare, Alectoria nigricans, Cetraria islandica, Cladonia arbuscula, Cladonia cervicornis, Cladonia coccifera, Cladonia crispata, Cladonia furcata, Cladonia gracilis, Cladonia impexa, Cladonia pyxidata, Cladonia rangiferina, Cladonia squamosa, Cladonia uncialis, Cornicularia aculeata, Ochrolechia frigida, Peltigera canina, Sphaerophorus globosus, Thamnolia vermicularis, Achillea millefolium, Antennaria dioica, Gnaphalium supinum, Solidago virgaurea, Campanula rotundifolia, Succisa pratensis, Minuartia sedoides, Silene acaulis, Vaccinium vitis-idaea, Thymus praecox, Armeria maritima, Polygonum viviparum, Rumex acetosa, Alchemilla alpina, Potentilla erecta, Sibbaldia procumbens, Galium saxatile, Viola palustris, Viola riviniana, Agrostis capillaris, Agrostis vinealis, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Nardus stricta

U11 — High montane heath and snow bed, Lowland dry acid grassland, Upland dry heath

Polytrichum sexangulare-Kiaeria starkei snow-bed

Empetrum nigrum, Salix herbacea, Carex bigelowii, Juncus trifidus, Huperzia selago, Conostomum tetragonum, Pohlia drummondii, Pohlia ludwigii, Pohlia nutans, Dicranum fuscescens, Kiaeria falcata, Kiaeria starkei, Racomitrium canescens sens.lat., Racomitrium fasciculare, Racomitrium heterostichum, Racomitrium lanuginosum, Pleurozium schreberi, Rhytidiadelphus loreus, Oligotrichum hercynicum, Polytrichastrum alpinum, Polytrichastrum sexangulare, Anthelia juratzkana, Barbilophozia floerkei, Lophozia sudetica, Marsupella emarginata, Moerckia blyttii, Nardia scalaris, Pleurocladula albescens, Cetraria islandica, Cladonia bellidiflora, Cladonia pyxidata, Cladonia uncialis, Solorina crocea, Gnaphalium supinum, Cerastium cerastoides, Silene acaulis, Alchemilla alpina, Sibbaldia procumbens, Galium saxatile, Saxifraga stellaris, Viola palustris, Agrostis capillaris, Deschampsia cespitosa, Deschampsia flexuosa, Festuca vivipara, Nardus stricta, Cryptogramma crispa, Blechnum spicant, Athyrium distentifolium

U12 — High montane heath and snow bed, Upland dry heath

Salix herbacea-Racomitrium heterostichum snow-bed

Salix herbacea, Carex bigelowii, Juncus trifidus, Luzula spicata, Huperzia selago, Andreaea rupestris, Conostomum tetragonum, Pohlia nutans, Dicranum scoparium, Kiaeria starkei, Racomitrium fasciculare, Racomitrium heterostichum, Racomitrium lanuginosum, Oligotrichum hercynicum, Polytrichastrum alpinum, Polytrichastrum sexangulare, Polytrichum piliferum, Barbilophozia floerkei, Diplophyllum albicans, Gymnomitrion concinnatum, Gymnomitrion corallioides, Lophozia sudetica, Marsupella brevissima, Nardia scalaris, Cetraria delisei, Cetraria islandica, Cladonia bellidiflora, Cladonia coccifera, Cladonia gracilis, Cladonia pyxidata, Cladonia uncialis, Cornicularia aculeata, Ochrolechia frigida, Gnaphalium supinum, Silene acaulis, Alchemilla alpina, Galium saxatile, Agrostis canina, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Nardus stricta

U13 — High montane heath and snow bed, Upland dry heath

Deschampsia cespitosa-Galium saxatile grassland

Vaccinium myrtillus, Salix herbacea, Carex bigelowii, Carex pilulifera, Luzula multiflora, Luzula sylvatica, Diphasiastrum alpinum, Huperzia selago, Selaginella selaginoides, Pohlia nutans, Kiaeria starkei, Racomitrium lanuginosum, Hylocomium splendens, Hypnum callichroum, Hypnum cupressiforme, Plagiothecium undulatum, Pleurozium schreberi, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sanionia uncinata, Polytrichastrum alpinum, Polytrichum commune, Sphagnum capillifolium, Sphagnum russowii, Anastrepta orcadensis, Barbilophozia floerkei, Barbilophozia lycopodioides, Nardia scalaris, Ptilidium ciliare, Cetraria islandica, Cladonia gracilis, Peltigera canina, Achillea millefolium, Gnaphalium supinum, Saussurea alpina, Campanula rotundifolia, Cerastium alpinum, Cerastium fontanum, Minuartia sedoides, Silene acaulis, Vaccinium vitis-idaea, Thymus praecox, Euphrasia frigida, Oxalis acetosella, Armeria maritima, Polygonum viviparum, Rumex acetosa, Ranunculus acris, Alchemilla alpina, Alchemilla filicaulis, Alchemilla glabra, Potentilla erecta, Sibbaldia procumbens, Galium saxatile, Saxifraga hypnoides, Saxifraga stellaris, Viola palustris, Viola riviniana, Agrostis canina, Agrostis capillaris, Anthoxanthum odoratum, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Nardus stricta, Blechnum spicant, Dryopteris dilatata

U14 — High montane heath and snow bed, Upland dry heath

Alchemilla alpina-Sibbaldia procumbens dwarf-herb community

Vaccinium myrtillus, Salix herbacea, Carex bigelowii, Carex pilulifera, Juncus trifidus, Luzula multiflora, Luzula spicata, Diphasiastrum alpinum, Huperzia selago, Selaginella selaginoides, Andreaea alpina, Pohlia nutans, Dicranum scoparium, Racomitrium aquaticum, Racomitrium canescens sens.lat., Racomitrium fasciculare, Racomitrium heterostichum, Racomitrium lanuginosum, Ctenidium molluscum, Hylocomium splendens, Hypnum callichroum, Pleurozium schreberi, Rhytidiadelphus loreus, Rhytidiadelphus squarrosus, Rhytidiadelphus triquetrus, Sanionia uncinata, Oligotrichum hercynicum, Pogonatum urnigerum, Polytrichastrum alpinum, Polytrichum piliferum, Barbilophozia floerkei, Diplophyllum albicans, Lophozia sudetica, Nardia scalaris, Ptilidium ciliare, Cetraria islandica, Cladonia arbuscula, Cladonia bellidiflora, Cladonia pyxidata, Achillea millefolium, Gnaphalium supinum, Scorzoneroides autumnalis, Campanula rotundifolia, Cerastium alpinum, Cerastium fontanum, Minuartia sedoides, Sagina saginoides, Silene acaulis, Thymus praecox, Euphrasia officinalis, Armeria maritima, Polygonum viviparum, Rumex acetosa, Ranunculus acris, Thalictrum alpinum, Trollius europaeus, Alchemilla alpina, Alchemilla filicaulis, Alchemilla glabra, Potentilla erecta, Sibbaldia procumbens, Galium saxatile, Saxifraga hypnoides, Saxifraga oppositifolia, Saxifraga stellaris, Viola palustris, Agrostis canina, Agrostis capillaris, Anthoxanthum odoratum, Deschampsia cespitosa, Deschampsia flexuosa, Festuca ovina, Festuca rubra, Nardus stricta, Blechnum spicant, Botrychium lunaria