Dense brittlestars with sparse Ascidia mentula and Ciona intestinalis on sheltered circalittoral mixed substrata

English name: Dense brittlestars with sparse Ascidia mentula and Ciona intestinalis on sheltered circalittoral mixed substrata

Quick facts

EUNIS habitat type code A4.3112
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

This biotope is typically found on wave-sheltered sites (although it may be found in wave-exposed through to extremely wave-sheltered conditions), on circalittoral mixed substrata (Bedrock, boulders, cobbles, pebbles and gravel), subject to moderately strong to weak tidal streams. This biotope often has a silty appearance in parallel with A4.3111 but is characterised by a dense carpet of brittlestars (Ophiothrix fragilis, Ophiocomina nigra and to a lesser extent Ophiura albida) which virtually cover the seabed. Where the underlying substratum is visible, pink coralline crusts and the white calcareous tubes of the keelworm Pomatoceros triqueter are often observed. Hydroids and bryozoans are scarce, perhaps partly due to the smothering effect of the brittlestars and possibly due to the grazing pressure of the sea urchin Echinus esculentus which is occasionally recorded. Other echinoderms present include Asterias rubens and Crossaster papposus. The solitary ascidian Ciona intestinalis may be seen attached to isolated rocks and boulders, whilst on the tops and sides of larger boulders, dead man's fingers Alcyonium digitatum may be recorded. The hermit crab Pagurus bernhardus is often recorded, whilst under boulders and in crevices the claws belonging to the long-clawed squat lobster Munida rugosa may be seen.
Situation: A4.3112 is found in predominantly sheltered areas, so in the infralittoral zone above, kelp forest formed by dense Laminaria saccharina and cape-form Laminaria hyperborea are frequently recorded. A dense understorey of red algae is also present.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Alcyonium digitatum
Invertebrates Asterias rubens
Invertebrates Ciona intestinalis
Invertebrates Crossaster papposus
Invertebrates Echinus esculentus
Algae Laminaria hyperborea
Algae Laminaria saccharina
Invertebrates Munida rugosa
Invertebrates Ophiocomina nigra
Invertebrates Ophiothrix fragilis
Invertebrates Ophiura albida
Invertebrates Pagurus bernhardus
Invertebrates Pomatoceros triqueter
Species scientific name English common name Species group
Alcyonium digitatum Invertebrates
Asterias rubens Invertebrates
Ciona intestinalis Invertebrates
Crossaster papposus Invertebrates
Echinus esculentus Invertebrates
Laminaria hyperborea Algae
Laminaria saccharina Algae
Munida rugosa Invertebrates
Ophiocomina nigra Invertebrates
Ophiothrix fragilis Invertebrates
Ophiura albida Invertebrates
Pagurus bernhardus Invertebrates
Pomatoceros triqueter Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.LCR.BrAs.AmenCio.Bri Dense brittlestars with sparse <I>Ascidia mentula</I> and <I>Ciona intestinalis</I> on sheltered circalittoral mixed substrata source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A4.3112 Dense brittlestars with sparse Ascidia mentula and Ciona intestinalis on sheltered circalittoral mixed substrata same
EUNIS Habitat Classification 200308 A3.651 Ophiothrix fragilis and/or Ophiocomina nigra beds on slightly tide-swept circalittoral rock or mixed substrata wider
EUNIS Habitat Classification 200202 A3.651 Ophiothrix fragilis and/or Ophiocomina nigra beds on slightly tide-swept circalittoral rock or mixed substrata overlap
EUNIS Habitat Classification 199910 A3.651 Ophiothrix fragilis and/or Ophiocomina nigra beds on slightly tide-swept circalittoral rock or mixed substrata overlap
MNCR BioMar 97.06 (Britain & Ireland) MCR.Bri.Oph Ophiothrix fragilis and/or Ophiocomina nigra beds on slightly tide-swept circalittoral rock or mixed substrata overlap
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100