Intertidal sediments dominated by aquatic angiosperms

Sheltered muddy shores where seagrasses and other salt-tolerant flowering plants grow

Sheltered, muddy shores where seagrasses and other salt-tolerant flowering plants grow © Keith Hiscock

The area between high and low water on some sheltered muddy shores can be home to marine flowering plants including eelgrass and the most salt-tolerant of saltmarsh plants.

Eelgrass cannot dry out completely and so is found in pools or where the shore is very muddy and remains damp.  Saltmarsh plants live higher up on the shore.  They can tolerate being covered by seawater to some degree, but do need at least a few dry days to establish their roots.  The beds may die back in winter, when temperatures are lower and wave action is stronger. 

Eelgrass and saltmarsh plants provide food for overwintering Brent geese, widgeon ducks, and mute and whooper swans. They also provide shelter and food for a wide range of creatures including crabs, spire shell snail, periwinkles and lugworms, and, when the tide comes in, for fish.

They also provide a natural coastal defence. By collecting and stabilising the shore sediments, the plants reduce erosion and act as a buffer against the power of the waves.

For the official habitat definition please see the documents listed below.


European distribution

Pioneer saltmarshes occur around the coasts of England and Wales.  Eelgrass beds are sparsely distributed around the UK coast, and particularly large beds can be found on the shores of Essex and north Kent.  Its full geographical range extends from the Mediterranean to south Norway.

Pioneer Saltmarsh Fact


Conservation status/need

  • Components of this habitat may form an important part of UK BAP Priority Habitats (BAP habitats are now Habitats of Principal Importance/Priority Habitats), OSPAR Threatened and/or declining habitats or those listed under Annex I of the Habitats Directive.
  • Dwarf eelgrass is a nationally scarce species.


Official habitat definition

EUNIS habitat A2.6 Littoral sediments dominated by aquatic angiosperms


Further information

JNCC Marine Habitat Classification

Marine Life Information Network

JNCC - UK BAP Priority Species and Habitats

UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008 (updated July 2010)

JNCC EUNIS habitat correlations table