Allen Confluence Gravels

Site of Special Scientific Interest · 54.9232, -2.3137

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Northumberland County North Pennines Scenic Area

Condition (Natural England)

Favourable (1)
UnitFeatureConditionArea (ha)Assessed
NY799587 — Favourable 4.78 2010-11-29

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

Coastal vegetated shingle, Fast flowing river and stream, High montane heath and snow bed

Geology & landscape

Landscape processes: Coastal

Description

Description The river gravels at the Allen Confluence support an outstanding assemblage of river margin invertebrates. This fauna is characteristic of riverine sand and shingle and is especially important because of the wide range of habitats present. These include consolidated sand and shingle, that is land which is only occasionally inundated and on the whole well vegetated, together with partially vegetated often unstable sand banks and shingle ridges which are subject to regular flooding. Partially vegetated sandy banks support two rare ground beetles Bembidion schueppelia and B. litorale as well as a water beetle Helophorus arvernicus in the muddy water margin. Flatter areas of sand support Clivina collaris, a ground beetle and a money spider Caviphantes saxetorum which lives under embedded stones. A small chafer Psammoporus sabuleti and another money spider Diplocephalus protuberans live higher up on the sandy riverbank, the latter probably also using the damp woodland. The fauna inhabiting the shingles includes ground beetles such as Bembidion monticoland B. stomoides, a small click beetle Fleutiauxellus maritimus, a large wolf spider Arctosa cinerea, which lives under large stones resting on the gravel and a third money spider Diplocephalus connatus, which is known in Britain only from this site and one other on the River Tyne. Damp woodland with a varied ground flora on the riverbank supports several uncommon moths including most notably the yellow tarred brindle Acasis viretata, black rustic Aporophyla nigra and plain wave Idaea straminata and the ground beetle Pterostichus cristatus, the national distribution of which is largely confined to Northumberland and Durham. Several additional species of rare spider including Centromerus persimilis, Mioxenablanda and Jacksonella falconeri were recorded here at the turn of the century, but have not been re-discovered in recent times. Further survey can be expected to locate many more interesting species, especially when a wider range of invertebrates are investigated. Alpine penny cress Noccaea caerulescens occurs on older river deposits indicating some contamination by heavy metals possibly resulting from mineral mining activity in the river catchment.

Species mentioned

English name
search for this in other sites		 Latin name
search with Google		 IUCN / Red List Type Family
chafer Psammoporus sabuleti Not listed in GB list beetle scarabaeidae
no common name Clivina collaris LC beetle ground carabidae
ground beetle Pterostichus cristatus NA beetle ground carabidae
water beetle Helophorus arvernicus Not listed in GB list beetle water helophoridae
alpine pennycress Noccaea caerulescens VU herb brassicaceae
yellow-barred brindle Acasis viretata Not listed in GB list moth geometridae
black rustic Aporophyla nigra Not listed in GB list moth noctuidae
plain wave Idaea straminata Not listed in GB list moth geometridae
grey wolf spider Arctosa cinerea LC spider wolf lycosidae

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

MC6 — Coastal vegetated shingle, Hard cliff and cliff slope

Atriplex prostrata-Beta vulgaris ssp. maritima sea-bird cliff community

Daucus carota, Sonchus oleraceus, Taraxacum officianalis, Tripleurospermum maritimum, Cochlearia officinalis, Silene uniflora, Spergularia rupicola, Atriplex hastata, Malva arborea, Plantago coronopus, Armeria maritima, Polygonum aviculare, Rumex crispus, Bromus hordeaceous, Catapodium marinum, Dactylis glomerata, Festuca rubra

SD1 — Coastal vegetated shingle, Sand dune

Rumex crispus-Glaucium flavum shingle community

Solanum dulcamara, Crithmum maritimum, Cirsium arvense, Cirsium vulgare, Helminthotheca echioides, Hypochaeris radicata, Jacobaea vulgaris, Lactuca serriola, Leontodon saxatilis, Senecio viscosus, Sonchus arvensis, Sonchus asper, Tripleurospermum maritimum, Crambe maritima, Cerastium fontanum, Honckenya peploides, Sagina apetala, Silene uniflora, Atriplex prostrata, Sedum acre, Euphorbia paralias, Lathyrus japonicus, Geranium robertianum, Glaucium flavum, Plantago coronopus, Plantago lanceolata, Rumex crispus, Potentilla anserina, Ammophila arenaria, Arrhenatherum elatius, Elytrigia atherica, Elytrigia juncea, Festuca rubra, Holcus lanatus, Lolium perenne

SD2 — Coastal vegetated shingle, Sand dune

Honkenya peploides-Cakile maritima strandline community

Salsola kali, Achillea millefolium, Cirsium arvense, Eryngium maritimum, Hypochaeris radicata, Senecio vulgaris, Sonchus arvensis, Tripleurospermum maritimum, Cakile maritima, Cerastium diffusum, Honckenya peploides, Silene uniflora, Stellaria media agg., Atriplex glabriuscula, Atriplex laciniata, Atriplex littoralis, Atriplex patula, Atriplex prostrata, Sedum acre, Polygonum oxyspermum subsp. Raii, Rumex crispus, Potentilla anserina, Agrostis stolonifera, Ammophila arenaria, Arrhenatherum elatius, Elytrigia juncea, Elytrigia repens, Festuca rubra, Leymus arenarius, Poa annua

SD3 — Coastal vegetated shingle, Sand dune

Matricaria maritima-Galium aparine strandline community

Bolboschoenus maritimus, Juncus bufonius, Juncus gerardii, Ligusticum scoticum, Matricaria discoidea, Sonchus arvensis, Sonchus asper, Tripleurospermum maritimum, Mertensia maritima, Cakile maritima, Cochlearia officinalis, Honckenya peploides, Stellaria media agg., Atriplex glabriuscula, Atriplex patula, Atriplex prostrata, Triglochin maritimum, Plantago maritima, Armeria maritima, Rumex crispus, Glaux maritima, Galium aparine, Agrostis stolonifera, Elytrigia repens, Festuca rubra, Holcus lanatus, Leymus arenarius, Poa annua

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