Solitary ascidians, including Ascidia mentula and Ciona intestinalis, on wave-sheltered 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 A4.3111 and A4.3112. A4.3112 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 A4.311 |
---|---|
Bern Convention | Included in a Resolution 4 habitat type at a higher level (A4) |
Vegetation types
Relation to vegetation types (syntaxa)
Not availableSpecies mentioned in habitat description
Species scientific name | English common name | Species group |
---|---|---|
Alcyonium digitatum | Invertebrates | |
Antedon bifida | Invertebrates | |
Ascidia mentula | Invertebrates | |
Asterias rubens | Invertebrates | |
Cancer pagurus | Invertebrates | |
Caryophyllia smithii | Invertebrates | |
Ciona intestinalis | Invertebrates | |
Echinus esculentus | Invertebrates | |
Metridium senile | Invertebrates | |
Ophiocomina nigra | Invertebrates | |
Ophiothrix fragilis | Invertebrates | |
Ophiura albida | Invertebrates |
Other classifications
Classification | Code | Habitat type name | Relationship type |
---|---|---|---|
Marine Habitat Classification Britain/Ireland 0405 | CR.LCR.BrAs.AmenCio | Solitary ascidians, including <I>Ascidia mentula</I> and <I>Ciona intestinalis</I>, on wave-sheltered circalittoral rock | source |
CORINE Land Cover | 5.2.3. | Sea and ocean | n/a |
History
Classification | Code | Habitat type name | Relationship type |
---|---|---|---|
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 |