Large solitary ascidians and erect sponges on wave-sheltered circalittoral rock

English name: Large solitary ascidians and erect sponges on wave-sheltered circalittoral rock

Quick facts

EUNIS habitat type code A4.312
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

A4.312 is characteristic of the wave-sheltered conditions found in the Kenmare River on the west coast of Ireland. This biotope is typically found on silty circalittoral bedrock and boulders in wave-sheltered channels subject to varying amounts of tidal flow. These fully marine inlets and channels have steep, often vertical sides with small terraces or ledges. This biotope, characterised by erect sponges and large solitary ascidians, appears to be biologically diverse. A diverse ascidian fauna is generally present, including Ascidia mentula, Aplidium punctum, Corella parallelogramma, Ascidia virginea, Botryllus schlosseri, Clavelina lepadiformis and Ciona intestinalis. An equally diverse sponge fauna, with massive erect sponges particularly noticeable, compliments these species. Dominant species include Esperiopsis fucorum, Dysidea fragilis, Tethya aurantium, Polymastia boletiformis, Raspailia ramosa, Stelligera stuposa, Polymastia mamilliaris and Pachymatisma johnstonia. Other sponges present are Suberites carnosus, Haliclona fistulosa, Stelligera rigida, Mycale rotalis, Haliclona simulans, Iophon hyndmani and Hemimycale columella. Various sponge crusts may also be present but in most cases in lower abundances. Other significant components of the community include the cup coral Caryophyllia smithii and various echinoderms, including the sea urchin Echinus esculentus and the starfish Henricia oculata and Marthasterias glacialis. Small isolated clumps of Nemertesia antennina and individual Alcyonium digitatum may be seen, whilst the top shell Calliostoma zizyphinum may also be present. At present, there are relatively few records in this biotope, as it is only reported from around the south-western coast of Ireland, where sponge diversity is very high.
Situation: Due to the sheltered nature of the biotope, this unit is usually situated on bedrock/boulder outcrops associated with mud slopes and plains. Typical species found within these circalittoral muds include the seapen Virgularia mirablis and the anemone Pachycerianthus multiplicatus. In the infralittoral zone, sheltered kelp biotopes such as A5.521 with Laminaria saccharina occur frequently. In areas where there is a slightly stronger tidal-stream, the circalittoral muddy plains become more muddy gravel plains and slopes. Typical species found within these habitats include the anemones Mesacmaea mitchellii and Aureliana heterocera. When tidal-streams becomes negligible, but with similar wave-sheltered conditions, you tend to find A4.2111 biotopes occurring, especially in the same geographical location (around south-west/west Ireland) as A4.312.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Alcyonium digitatum
Invertebrates Aplidium punctum
Invertebrates Ascidia mentula
Invertebrates Ascidia virginea
Invertebrates Aureliana heterocera
Invertebrates Botryllus schlosseri
Invertebrates Calliostoma zizyphinum
Invertebrates Caryophyllia smithii
Invertebrates Ciona intestinalis
Invertebrates Clavelina lepadiformis
Invertebrates Corella parallelogramma
Invertebrates Dysidea fragilis
Invertebrates Echinus esculentus
Invertebrates Esperiopsis fucorum
Invertebrates Haliclona fistulosa
Invertebrates Haliclona simulans
Invertebrates Hemimycale columella
Invertebrates Henricia oculata
Invertebrates Iophon hyndmani
Algae Laminaria saccharina
Invertebrates Marthasterias glacialis
Invertebrates Mycale rotalis
Invertebrates Nemertesia antennina
Invertebrates Pachycerianthus multiplicatus
Invertebrates Pachymatisma johnstonia
Invertebrates Polymastia boletiformis
Invertebrates Raspailia ramosa
Invertebrates Stelligera rigida
Invertebrates Stelligera stuposa
Invertebrates Suberites carnosus
Invertebrates Tethya aurantium
Species scientific name English common name Species group
Alcyonium digitatum Invertebrates
Aplidium punctum Invertebrates
Ascidia mentula Invertebrates
Ascidia virginea Invertebrates
Aureliana heterocera Invertebrates
Botryllus schlosseri Invertebrates
Calliostoma zizyphinum Invertebrates
Caryophyllia smithii Invertebrates
Ciona intestinalis Invertebrates
Clavelina lepadiformis Invertebrates
Corella parallelogramma Invertebrates
Dysidea fragilis Invertebrates
Echinus esculentus Invertebrates
Esperiopsis fucorum Invertebrates
Haliclona fistulosa Invertebrates
Haliclona simulans Invertebrates
Hemimycale columella Invertebrates
Henricia oculata Invertebrates
Iophon hyndmani Invertebrates
Laminaria saccharina Algae
Marthasterias glacialis Invertebrates
Mycale rotalis Invertebrates
Nemertesia antennina Invertebrates
Pachycerianthus multiplicatus Invertebrates
Pachymatisma johnstonia Invertebrates
Polymastia boletiformis Invertebrates
Raspailia ramosa Invertebrates
Stelligera rigida Invertebrates
Stelligera stuposa Invertebrates
Suberites carnosus Invertebrates
Tethya aurantium Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.LCR.BrAs.LgAsSp Large solitary ascidians and erect sponges on wave-sheltered circalittoral rock 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 A4.312 Large solitary ascidians and erect sponges on wave-sheltered circalittoral rock same
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