EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A4 - Circalittoral rock and other hard substrata > A4.1 - Atlantic and Mediterranean high energy circalittoral rock > A4.13 - Mixed faunal turf communities on circalittoral rock > A4.133 - Mixed turf of hydroids and large ascidians with Swiftia pallida and Caryophyllia smithii on weakly tide-swept circalittoral rock

Mixed turf of hydroids and large ascidians with Swiftia pallida and Caryophyllia smithii on weakly tide-swept circalittoral rock

English name: Mixed turf of hydroids and large ascidians with Swiftia pallida and Caryophyllia smithii on weakly tide-swept circalittoral rock

Quick facts

EUNIS habitat type code A4.133
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

This biotope typically occurs from exposed through to sheltered circalittoral bedrock or boulders subject to moderately strong to weak tidal streams. It is found in water depths ranging from 4m to 37m. This biotope is distinguished by frequently occurring Swiftia pallida, abundant Caryophilia smithii and a diverse range of ascidians including Clavelina lepadiformis, Ascidia mentula, Polycarpa pomaria, Diazona violacea and Corella parallelogramma. A sparse, yet diverse hydroid turf is often apparent, with species such as Aglaophenia tubulifera, Nemertesia antennina, Polyplumaria frutescens, Halecium halecinum, Abietinaria abietina, Nemertesia ramosa and Halopteris catharina often recorded. Spaces amongst the turf are usually colonised by the polychaete Pomatoceros triqueter and encrusting red algae. Crinoids such as Antedon petasus, Antedon bifida and Leptometra celtica may be seen filter feeding on the tops of outcrops and boulders, along with the soft coral Alcyonium digitatum. Other echinoderms such as Echinus esculentus, Crossaster papposus and Asterias rubens may also be recorded. There may also be a bryozoan component to the sparse faunal turf. Species such as Securiflustra securifrons and Eucratea loricata as well as the crustose Parasmittina trispinosa are all usually present. There may be a few isolated growths of sponge, such as Iophonopsis nigricans, Axinella infundibuliformis and Haliclona urceolus. Other species that may be present include the brachiopod Terebratulina retusa and the top shell Calliostoma zizyphinum. The crustacean Munida rugosa may be visible in crevices. All records are from the west coast of Scotland (east coast of Lewis /Outer Hebrides).
Situation: Above this biotope, kelp forests and parks are typically found in the infralittoral, with Laminaria saccharina and Laminaria hyperborea. This biotope is found in Scottish Sealochs and, in the most sheltered situations, may graduate into unit A4.314 at greater depths.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Algae Laminaria hyperborea
Algae Laminaria saccharina
Invertebrates Abietinaria abietina
Invertebrates Aglaophenia tubulifera
Invertebrates Alcyonium digitatum
Invertebrates Antedon bifida
Invertebrates Antedon petasus
Invertebrates Ascidia mentula
Invertebrates Asterias rubens
Invertebrates Axinella infundibuliformis
Invertebrates Calliostoma zizyphinum
Invertebrates Clavelina lepadiformis
Invertebrates Corella parallelogramma
Invertebrates Crossaster papposus
Invertebrates Diazona violacea
Invertebrates Echinus esculentus
Invertebrates Eucratea loricata
Invertebrates Halopteris catharina
Invertebrates Leptometra celtica
Invertebrates Munida rugosa
Invertebrates Nemertesia antennina
Invertebrates Nemertesia ramosa
Invertebrates Parasmittina trispinosa
Invertebrates Polycarpa pomaria
Invertebrates Pomatoceros triqueter
Invertebrates Securiflustra securifrons
Invertebrates Swiftia pallida
Invertebrates Terebratulina retusa
Species scientific name English common name Species group
Laminaria hyperborea Algae
Laminaria saccharina Algae
Abietinaria abietina Invertebrates
Aglaophenia tubulifera Invertebrates
Alcyonium digitatum Invertebrates
Antedon bifida Invertebrates
Antedon petasus Invertebrates
Ascidia mentula Invertebrates
Asterias rubens Invertebrates
Axinella infundibuliformis Invertebrates
Calliostoma zizyphinum Invertebrates
Clavelina lepadiformis Invertebrates
Corella parallelogramma Invertebrates
Crossaster papposus Invertebrates
Diazona violacea Invertebrates
Echinus esculentus Invertebrates
Eucratea loricata Invertebrates
Halopteris catharina Invertebrates
Leptometra celtica Invertebrates
Munida rugosa Invertebrates
Nemertesia antennina Invertebrates
Nemertesia ramosa Invertebrates
Parasmittina trispinosa Invertebrates
Polycarpa pomaria Invertebrates
Pomatoceros triqueter Invertebrates
Securiflustra securifrons Invertebrates
Swiftia pallida Invertebrates
Terebratulina retusa Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.HCR.XFa.SwiLgAs Mixed turf of hydroids and large ascidians with <I>Swiftia pallida</I> and <I>Caryophyllia smithii</I> on weakly tide-swept 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 A4.133 Mixed turf of hydroids and large ascidians with Swiftia pallida and Caryophyllia smithii on weakly tide-swept circalittoral rock same
EUNIS Habitat Classification 200308 A3.614 Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock wider
EUNIS Habitat Classification 200308 A4.446 Crinoids Leptometra celtica narrower
EUNIS Habitat Classification 200202 A4.446 Crinoids Leptometra celtica overlap
EUNIS Habitat Classification 200202 A3.614 Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock overlap
EUNIS Habitat Classification 199910 A3.614 Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock overlap
MNCR BioMar 97.06 (Britain & Ireland) MCR.XFa.ErSSwi Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock overlap
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