EUNIS habitat classification 2017 > M - Marine benthic habitats > MC1 - Circalittoral rock > MC12 - Atlantic circalittoral rock > MC123 - Brachiopod and ascidian communities on Atlantic circalittoral rock > MC1231 - Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on wave-sheltered Atlantic circalittoral rock

Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on wave-sheltered Atlantic circalittoral rock

Description (English)

This biotope predominantly occurs on the upper faces of wave-sheltered (often sealochs) circalittoral bedrock, boulder and cobble slopes with little tidal flow. Apart from the solitary ascidians Ciona intestinalis and Ascidia mentula, this biotope has a rather barren, pink appearance (due to the encrusting red algae), possibly due to grazing pressure from the sea urchin Echinus esculentus. Other organisms found encrusting the rocky surface include the polychaete Pomatoceros triqueter and the cup coral Caryophyllia smithii. Other species occasionally encountered include Alcyonium digitatum, Asterias rubens, Pagurus berhardus, Crossaster papposus, Antedon bifida and Metridium senile. Crustaceans such as Munida rugosa and Cancer pagurus may be recorded in crevices. Two variants of this biotope exist: Units MC1-2311 and MC1-2312. MC1-2312 occurs where is a dense carpet of brittlestars which sometimes completely cover the rocky substratum. Species present include Ophiothrix fragilis, Ophiocomina nigra and Ophiura albida.
Temporal variation: The abundance of C. intestinalis tends to fluctuate seasonally, so it may appear absent at a site at one time of year and then be present at other times, altering the visual appearance of the biotope. Other solitary ascidian species such as A. mentula and Ascidiella aspersa tend to be longer-lived (approximately 7 years and 3 years, respectively).

Source: EUNIS habitat classification

Quick facts

EUNIS habitat type code MC1231
Relation to Resolution 4 habitat type (used for designation of Emerald sites)

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Alcyonium digitatum
Invertebrates Antedon bifida
Invertebrates Ascidia mentula
Invertebrates Ascidiella aspersa
Invertebrates Asterias rubens
Invertebrates Cancer pagurus
Invertebrates Caryophyllia smithii
Invertebrates Ciona intestinalis
Invertebrates Crossaster papposus
Invertebrates Echinus esculentus
Invertebrates Metridium senile
Invertebrates Munida rugosa
Invertebrates Ophiocomina nigra
Invertebrates Ophiothrix fragilis
Invertebrates Ophiura albida
Invertebrates Pomatoceros triqueter
Species scientific name English common name Species group
Alcyonium digitatum Invertebrates
Antedon bifida Invertebrates
Ascidia mentula Invertebrates
Ascidiella aspersa Invertebrates
Asterias rubens Invertebrates
Cancer pagurus Invertebrates
Caryophyllia smithii Invertebrates
Ciona intestinalis Invertebrates
Crossaster papposus Invertebrates
Echinus esculentus Invertebrates
Metridium senile Invertebrates
Munida rugosa Invertebrates
Ophiocomina nigra Invertebrates
Ophiothrix fragilis Invertebrates
Ophiura albida Invertebrates
Pomatoceros triqueter Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 2007 (revised descriptions 2012) A4.311 Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on wave-sheltered circalittoral rock same
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type Comment
EUNIS Habitat Classification 200410 A4.311 Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on wave-sheltered circalittoral rock same
EUNIS Habitat Classification 200308 A3.713 Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on wave-sheltered circalittoral rock same
EUNIS Habitat Classification 200202 A3.713 Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on very sheltered circalittoral rock same
EUNIS Habitat Classification 199910 A3.713 Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on very sheltered circalittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) SCR.BrAs.AmenCio Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on very sheltered circalittoral rock same
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