EUNIS habitat classification 2017 > M - Marine benthic habitats > MC2 - Circalittoral biogenic habitat > MC22 - Atlantic circalittoral biogenic habitat > MC223 - Bivalve reefs in the Atlantic circalittoral zone > MC2234 - Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered Atlantic circalittoral mixed substrata

Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered Atlantic circalittoral mixed substrata

Description (English)

Dense Modiolus modiolus beds, covered by hydroids and bryozoans, on soft gravelly, shelly mud with pebbles in areas of slight or moderate tidal currents. The variable scallop (Chlamys varia) is frequently found in large numbers amongst the Modiolus shells. Hydroids such as Halecium spp. and Kirchenpaueria pinnata and ascidians such as Ascidiella aspersa, Corella parallelogramma and Ciona intestinalis may be found attached to pebbles or mussel shells. The echinoderms Ophiothrix fragilis and Antedon bifida are often frequent in this biotope as is the encrusting polychaete Pomatoceros triqueter. Similar communities have been found on cobble and pebble plains in stable, undisturbed conditions in some sealochs, although not all these examples have Modiolus beds.

Source: EUNIS habitat classification

Quick facts

EUNIS habitat type	code MC2234
Relation to	Resolution 4 habitat type (used for designation of Emerald sites)

Legal status

Relation to other habitat types mentioned in legal instruments

Legal text	Annex	Name in legal text	Code in legal text	Habitat type relationship	More information
Convention on the conservation of European wildlife and natural habitats	Revised Annex I of Resolution 4 (1996) of the Bern Convention on endangered natural habitats types using the EUNIS habitat classification (year of revision 2010)	Reefs	1170	Narrower	https://wcd.coe.int/ViewDoc....ckColorLogged=FDC864 Resolution No. 4 (1996) of the Bern Convention lists endangered natural habitats requiring specific conservation measures [and the designation of Areas of Special Conservation Interest (ASCIs) forming the Emerald network]

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Antedon bifida

Invertebrates Chlamys varia

Invertebrates Ciona intestinalis

Invertebrates Kirchenpaueria pinnata

Invertebrates Modiolus modiolus

Invertebrates Ophiothrix fragilis

Species scientific name	English common name	Species group
Antedon bifida		Invertebrates
Chlamys varia		Invertebrates
Ciona intestinalis		Invertebrates
Kirchenpaueria pinnata		Invertebrates
Modiolus modiolus		Invertebrates
Ophiothrix fragilis		Invertebrates

Other classifications

Classification	Code	Habitat type name	Relationship type
EUNIS Habitat Classification 2007 (revised descriptions 2012)	A5.624	Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata	same

For relation to plant communities (syntaxa), see Vegetation types

History

Classification	Code	Habitat type name	Relationship type
EUNIS Habitat Classification 200410	A5.624	Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata	same
EUNIS Habitat Classification 200308	A3.721	Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata	same
EUNIS Habitat Classification 200202	A3.721	Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata	same
EUNIS Habitat Classification 199910	A3.721	Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata	same
MNCR BioMar 97.06 (Britain & Ireland)	SCR.Mod.ModCvar	Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata	same

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