Mucking Flats and Marshes

Site of Special Scientific Interest · 51.4859, 0.4453

Condition (Natural England)

Unfavourable Recovering (1) Favourable (3)
UnitFeatureConditionArea (ha)Assessed
TQ692773 Unfavourable Recovering 18.37 2015-09-03
TQ695774 Favourable 112.46 2015-09-03
TQ698797 Favourable 87.85 2015-09-03
TQ704809 Favourable 94.03 2016-03-03

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

Landscape processes: Coastal

Birds & fish recorded

Birds

SpeciesSeason
avocet Passage
avocet Roosting
avocet Wintering
black-tailed godwit Passage
black-tailed godwit Roosting
black-tailed godwit Wintering
curlew Passage
curlew Roosting
curlew sandpiper Passage
curlew sandpiper Roosting
dunlin Passage
dunlin Roosting
dunlin Wintering
grey plover Passage
grey plover Roosting
grey plover Wintering
redshank Passage
redshank Roosting
redshank Wintering
ringed plover Passage
ringed plover Roosting
ringed plover Wintering
shelduck Passage
shelduck Roosting
shelduck Wintering

Description

Description Mucking Flats and Marshes comprise an extensive stretch of Thames mud flats and saltmarsh, together with sea wall grassland. Wintering wildfowl and waders reach both nationally and internationally important numbers on the mud flats, roosting and feeding on adjacent saltmarsh and disused silt lagoons. The mud flats form the largest intertidal feeding area for wintering wildfowl and waders west of Canvey Island on the north bank of the Thames. Ringed plover occur in internationally important numbers, with nationally important populations of shelduck, grey plover, dunlin, black-tailed godwit and redshank. Other species occur in good numbers, with avocet regularly present, sometimes in nationally important numbers. The mud flats and saltmarsh are also an important staging post for passage migrants, with significant numbers of waders such as curlew sandpiper and an important late summer flock of yellow legged herring gulls. The saltmarshes provide important high tide roosts, as do the disused silt lagoons at Coalhouse Fort. The value of the site is enhanced by its proximity to Cliffs and Cooling Marshes SSSI and Higham Marshes SSSI across the Thames in Kent, with which there is an interchange of roosting and feeding birds. Between the sea wall and mean high water line lie areas of high level saltmarsh of a type uncommon in Essex. The vegetation is dominated by sea couch Elytrigia atherica and sea purslane Atriplex portulacoides, with sea aster Aster tripolium, common sea lavender Limonium vulgare and common saltmarsh grass Puccinellia maritima. Fragments of lower saltmarsh include glasswort Salicornia spp., common cordgrass Spartina anglica and lesser sea spurrey Spergularia marina, together with the nationally scarce golden samphire Inula crithmoides. The saltmarshes are truncated to their landward edge by sea walls, which in places are vegetated with a sward dominated by sea couch Elytrigia atherica. The saltmarsh has a high invertebrate interest, which includes the rare spider Praestigia duffeyi, as well as many notable and local species.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
shelduck Tadorna tadorna EN (NonBreeding), EN (Breeding) bird-duck anatidae
dunlin Calidris alpina EN (NonBreeding) bird-wader scolopacidae
curlew sandpiper Calidris ferruginea None bird-wader scolopacidae
black-tailed godwit Limosa limosa LC (NonBreeding) bird-wader scolopacidae
curlew Numenius arquata EN (Breeding) bird-wader scolopacidae
grey plover Pluvialis squatarola VU (NonBreeding) bird-wader charadriidae
avocet Recurvirostra avosetta LC (NonBreeding), LC (Breeding) bird-wader recurvirostridae
redshank Tringa totanus EN (NonBreeding) bird-wader scolopacidae
sea couch Elytrigia atherica Not listed in GB list grass poaceae
saltmarsh grass Puccinellia maritima LC grass poaceae
common cord grass Spartina anglica LC grass poaceae
sea aster Aster tripolium Not listed in GB list herb asteraceae
golden samphire Inula crithmoides Not listed in GB list herb asteraceae
common sea lavender Limonium vulgare NT herb plumbaginaceae
sea spurrey Spergularia marina LC herb carophyllaceae
sea purslane Atriplex portulacoides LC shrub dwarf chenopodiaceae
Duffey's bell-head spider Praestigia duffeyi EN spider linyphiidae

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