1310 Salicornia and other annuals colonising mud and sand
Description and ecological characteristics
This pioneer saltmarsh vegetation colonises intertidal mud and sandflats in areas protected from strong wave action and is an important precursor to the development of more stable saltmarsh vegetation. It develops at the lower reaches of saltmarshes where the vegetation is frequently flooded by the tide, and can also colonise open creek sides, depressions or pans within saltmarshes, as well as disturbed areas of upper saltmarshes.
There is little variation within this habitat type, which typically comprises a small number of species. The following NVC types are represented:
- SM7 Arthrocnemum perenne stands
- SM8 Annual Salicornia salt-marsh community
- SM9 Suaeda maritima salt-marsh community
- SM27 Ephemeral salt-marsh vegetation with Sagina maritima
The first three communities include open stands of perennial glasswort Sarcocornia perennis, glasswort Salicornia spp., or annual seablite Suaeda maritima. The density of these plants can vary and may be lower on sites with sandier substrates. Other species that may be found include common saltmarsh-grass Puccinellia maritima, common cord-grass Spartina anglica and sea aster Aster tripolium. Sarcocornia perennis is absent from Scotland. A further form of the habitat (SM27) consists of ephemeral vegetation colonising open pans in upper saltmarshes. Characteristic plants of this vegetation type include sea pearlwort Sagina maritima and knotted pearlwort S. nodosa.
European status and distribution
This form of saltmarsh vegetation is widely distributed throughout coastal areas of the EU.
UK status and distribution
There are over 2,300 ha of Salicornia and other annuals colonising mud and sand in the UK, and it is widespread in the saltmarshes of England and Wales. However, the area of the habitat type is restricted in Scotland and Northern Ireland because of a lack of new sediment for saltmarsh development.
Click here view UK distribution of this species
Carmarthen Bay and Estuaries/ Bae Caerfyrddin ac Aberoedd
East Wales, Extra-Regio, West Wales and The Valleys
Carmarthen Bay and Estuaries in south Wales is selected as representative of pioneer glasswort Salicornia spp. saltmarsh in the south-west of the UK. It forms an integral part of the estuarine system, supporting extensive pioneer communities and contributing to a complete sequence of saltmarsh vegetation, including transitions to upper saltmeadow and to important sand dune habitats.
Dee Estuary/ Aber Dyfrdwy
Cheshire, East Wales, Extra-Regio, Merseyside, West Wales and The Valleys
The Dee Estuary is representative of pioneer glasswort Salicornia spp. saltmarsh in the north-west of the UK. Salicornia spp. saltmarsh forms extensive stands in the Dee, especially on the more sandy muds where there is reduced tidal scour. It mainly occurs on the seaward fringes as a pioneer community, and moving landwards usually forms a transition to common saltmarsh-grass Puccinellia maritima saltmarsh (SM10). There is also a low frequency of Salicornia spp. extending well inland. Associated species often include annual sea-blite Suaeda maritima and hybrid scurvy grass Cochlearia x hollandica.
Dornoch Firth and Morrich More
Extra-Regio, Highlands and Islands
Dornoch Firth and Morrich More has the most extensive area of pioneer glasswort Salicornia spp. saltmarsh in Scotland. It is the most northerly site selected for this Annex I type, and represents the habitat type in the northern part of its range in the UK. It forms part of a complete transition from pioneer to upper saltmeadow and important sand dune habitats.
Glasswort Salicornia spp. saltmarsh in the Essex estuaries on the east coast of England forms an integral part of the transition from the extensive and varied intertidal mud and sandflats through to upper saltmeadows. Although the saltmarshes in this area are generally eroding, secondary pioneer communities appear as a precursor to erosion on the seaward edge of degraded mid-marsh communities. The area of pioneer marsh includes gradation into extensive cord-grass Spartina spp. swards.
Glannau Môn: Cors heli / Anglesey Coast: Saltmarsh
West Wales and The Valleys
This is part of a complex of saltmarsh and dune habitats lying either side of the dune systems at Newborough Warren, north Wales. It is therefore important in terms of the structural integrity of the site, which has been selected primarily for a range of sand dune Annex I types. The most significant stands of Salicornia spp. saltmarsh occur on Malltraeth Sands in the Cefni estuary.
Cumbria, Extra-Regio, Lancashire
Two types of pioneer saltmarsh are represented at Morecambe Bay in north-west England. Pioneer glasswort Salicornia spp. saltmarsh occurs intermittently along the coastline of the bay, forming a transition from the extensive intertidal sand and mudflats to the distinctive saltmeadows at this site. The sea pearlwort Sagina maritima community occurs in open pans on the upper marsh.
Cumbria, Extra-Regio, South Western Scotland
The pioneer glasswort Salicornia spp. saltmarsh in the Solway is part of a complete sequence of saltmarsh types, from pioneer communities through extensive mid-to high saltmarsh and transitions to tidal grazing marsh. It represents Salicornia and other annuals colonising mud and sand in north-west England and south-west Scotland. The pioneer marshes in this site develop in response to changing river channels and erosion of existing marsh and form part of a dynamic suite of maritime habitat types for which the site has been separately selected.
The Wash and North Norfolk Coast
East Anglia, Lincolnshire
The largest single area of this vegetation in the UK occurs at this site on the east coast of England, which is one of the few areas in the UK where saltmarshes are generally accreting. The proportion of the total saltmarsh vegetation represented by Salicornia and other annuals colonising mud and sand is high because of the extensive enclosure of marsh in this site. The vegetation is also unusual in that it forms a pioneer community with common cord-grass Spartina anglica in which it is an equal component. The inter-relationship with other habitats is significant, forming a transition to important dune, saltmeadow and halophytic scrub communities.
SACs where this Annex I habitat is a qualifying feature, but not a primary reason for site selection
- Drigg Coast Cumbria
- Humber Estuary East Yorkshire and Northern Lincolnshire, Extra-Regio, Lincolnshire
- Pen Llŷn a'r Sarnau/ Lleyn Peninsula and the Sarnau East Wales, Extra-Regio, West Wales and The Valleys
- Solent Maritime Extra-Regio, Hampshire and Isle of Wight, Surrey, East and West Sussex
- Strangford Lough Northern Ireland
Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.
Please note that the map shows sites where the presence of a feature is classed as ‘grade d’, but these sites are not listed. This is because ‘grade d’ indicates a non-significant presence.