Habitat account - Marine, coastal and halophytic habitats


1310 Salicornia and other annuals colonising mud and sand 

Background to selection

Distribution of SACs/SCIs/cSACs with habitat 1310 Salicornia and other annuals colonising mud and sand.  Click image for enlarged map.
Distribution of SACs/SCIs/cSACs with habitat 1310 Salicornia and other annuals colonising mud and sand. Click image for enlarged map.

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 Click to view UK distribution of this habitat

 

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.

Site selection rationale

 

Sites have been selected to cover the geographical range of the habitat type. Generally, the largest areas of the habitat type have been selected, and since it occurs as an integral part of a sequence of habitats, from sand/mudflats to more stable saltmarsh vegetation, preference has been given to sites where it forms part of well-developed successional sequences.


Site accounts

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.
Essex Estuaries Essex, Extra-Regio
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.
Morecambe Bay 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.
Solway Firth 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/SCIs/cSACs 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 Llyn 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.