Biodiversity & Conservation

Puccinellia maritima salt marsh community

LS.LMU.Sm.SM13


LMU.NVC_SM13

Image Kathy Duncan - Puccinellia maritima salt marsh. Image width ca 5 m.
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Distribution map

LS.LMU.Sm.SM13 recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)


  • EC_Habitats
  • UK_BAP

Marine natural heritage importance

Listed under EC Habitats Directive
UK Biodiversity Action Plan
National importance Not available
Habitat Directive feature (Annex 1) Estuaries
Lagoons

Biotope importance

Salt marshes are an important resource for wading birds and wildfowl. They act as high tide refuges for birds feeding on adjacent mudflats, as breeding sites for waders, gulls and terns and as a source of food for passerine birds particularly in autumn and winter. In winter, grazed salt marshes are used as feeding grounds by large flocks of wild ducks and geese (see ecological relationships). For example, Packham & Willis (1997) suggested that the UK coastline supported 1.5 -2 million waders during winter, which probably represented 50% of the European population. Packham & Liddle (1970) listed 250 species of birds that fed on the Cefni saltmarsh and adjacent tidal flats. Areas with high structural and plant diversity, particularly where freshwater seepage's provide a transition from fresh to brackish conditions, are particularly important for invertebrates. Salt marshes also provide sheltered nursery sites for several species of fish (Anon, 1999n). In addition, saltmarsh habitats support a number of nationally rare and scarce species or UK Biodiversity Action Plan species (see species composition).

Saltmarsh collects litter and detritus, from the resident population of plants and animals, and brought down rivers or in with the tides. The action of bacteria and invertebrates breaks down the detritus into particulate or dissolved organic nutrients. Saltmarsh habitats may be net exporters of nutrients to the wider community of estuaries or bays or net nutrient sinks depending on local conditions (Long & Mason, 1983; Adam, 1993). However, saltmarsh habitats are potentially important sources of organic carbon and productivity in some estuaries and bays.

The accumulation of sediment, and its consolidation by plants, results in a gradual seaward progression of the saltmarsh unless the marsh is eroded by storms or changes in the river channel. The low profile, raised bed and plant material attenuate wave action and water flow, reducing the impinging wave energy on the shore. Therefore, saltmarsh habitats, together with adjacent mudflats may form a natural, soft, coastal defense.

Exploitation

Areas of saltmarsh have been subject to land claim since medieval times. This practice continued until very recently; for instance, in the Wash, 858 ha of saltmarsh were converted to agricultural use between 1970 and 1980. The land enclosed by sea walls was originally converted to grazing marsh with brackish ditches, but since the 1940s large areas of grazing marsh have been agriculturally improved to grow arable crops. As a consequence, many salt marshes now adjoin arable land, and the upper and transitional zones of salt marshes have become comparatively scarce in England. Sites still displaying a full range of zonation are particularly valuable for nature conservation (Anon, 1999n)

Coastal saltmarsh is often used as a grazing resource for livestock such as sheep, cattle, and horses (see extraction). However, where grazing is part of the management regime for the saltmarsh, it can be beneficial, increasing species diversity and preventing succession to shrub habitats (Packham & Willis, 1997; Anon, 1999n).

Additional information icon Additional information

This biotope may be protected under 'Lagoons', 'Estuaries', and ' Atlantic salt meadows (Glauco-Puccinellietalia maritimae)' Annex I habitat types of the Habitats Directive.


This review can be cited as follows:

Tyler-Walters, H. 2004. Puccinellia maritima salt marsh community. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/10/2014]. Available from: <http://www.marlin.ac.uk/habitatimportance.php?habitatid=350&code=1997>