EUNIS habitat classification 2017 > M - Marine benthic habitats > MA2 - Littoral biogenic habitat > MA22 - Atlantic littoral biogenic habitat > MA227 - Bivalve reefs in the Atlantic littoral zone

Bivalve reefs in the Atlantic littoral zone

Quick facts

EUNIS habitat type code MA227
Relation to Resolution 4 habitat type (used for designation of Emerald sites)

Description (English)

Sediment shores characterised by beds of adult mussels Mytilus edulis occur principally on mid and lower eulittoral mixed substrata (mainly cobbles and pebbles on muddy sediments) in a wide range of exposure conditions. In high densities the mussels bind the substratum and provide a habitat for many infaunal and epifaunal species. This biotope is also found in lower shore tide-swept areas, such as in the tidal narrows of Scottish sealochs. A fauna of dense juvenile mussels may be found in sheltered firths, attached to algae on shores of pebbles, gravel, sand, mud and shell debris with a strandline of fucoid algae.
Situation: High densities of juvenile mussels attached to seaweed have been recorded from sheltered shores of the Dornoch Firth and Moray Firth. Adult mussel beds can be found below a band of ephemeral green seaweeds (MA4-211) on more exposed, predominantly rocky shores. On sheltered, predominantly rocky shores either a Fucus vesiculosus dominated biotope or a biotope dominated by the wrack Ascophyllum nodosum (MA1-23D2; MA1-23E2) can be found above, or the barnacle dominated biotope (MA1-2233).
Temporal variation: The temporal stability of mussel beds can vary a lot. Some beds are permanent, maintained by recruitment of spat in amongst adults. Other beds are ephemeral, an example of which are beds ocurring at South America Skear where large amounts of spat settle intermittently on a cobble basement. The mussels rapidly build up mud, and are unable to remain attached to the stable cobbles. They are then liable to be washed away during gales. A second example of ephemeral mussel dominated biotopes occurs when mussel spat ("mussel crumble") settles on the superficial shell of cockle beds, such as is known to occur in the Burry Inlet.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Algae Ascophyllum nodosum
Invertebrates Mytilus edulis
Species scientific name English common name Species group
Ascophyllum nodosum Algae
Mytilus edulis Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 2007 (revised descriptions 2012) A2.72 Littoral mussel beds on sediment narrower
European Red List of Habitats NEAA2.72 Mussel beds in the Atlantic littoral zone same
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type Comment
EUNIS Habitat Classification 200410 A2.72 Littoral Mytilus edulis beds on sediment same
EUNIS Habitat Classification 200308 A1.33 Mussel beds on sheltered littoral mixed substrata narrower
EUNIS Habitat Classification 200202 A1.33 Mussel beds on sheltered littoral mixed substrata same
EUNIS Habitat Classification 199910 A1.33 Mussel beds on sheltered littoral mixed substrata same
EUNIS Habitat Classification 199811 A1.33 Mussel beds on sheltered mixed substrata same
EUNIS Habitat Classification 199712 A1.43 Mussel beds on sheltered mixed substrata same
Palaearctic Habitat Classification 199905 11.254 Part of Mussel beds narrower
Palaearctic Habitat Classification 1997 11.254 Part of Mussel beds narrower
Palaearctic Habitat Classification 1996 11.254   narrower
Palaearctic Habitat Classification 1993 11.254   narrower
CORINE Biotopes Classification 1991 11.254   narrower
MNCR BioMar 97.06 (Britain & Ireland) SLR.MX Mytilus (mussel) beds (mixed substrata) same
MNCR BioMar 96.7 (Britain & Ireland) SLR.MytX   same
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