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Concept: [Flustra foliacea] and colonial ascidians on tide-swept moderately wave-exposed circalittoral rock in the eunishabitats vocabulary

Concept URI http://eunis.eea.europa.eu/eunishabitats/A4.134
Preferred label [Flustra foliacea] and colonial ascidians on tide-swept moderately wave-exposed circalittoral rock
Definition This biotope typically occurs on the upper faces of moderately tide-swept, moderately wave-exposed circalittoral bedrock or boulders (although a variant is found on mixed substrata). It most frequently occurs between 10-20m water depth. The biotope is exposed to varying amounts of scour (due to nearby patches of sediment) and, as a consequence, is characteristically dominated by dense [Flustra folicaea], a range of colonial ascidians and a variety of other scour/silt-tolerant species. In addition to [F. foliacea], other bryozoans present in this biotope include [Alcyonidium diaphanum], [Bugula flabellata] and [Bugula plumosa]. Varying amounts of the soft coral [Alcyonium digitatum] may be recorded, depending on the amount of scouring which may vary locally. Where scour is a major factor, species such as the scour-tolerant [Urticina felina] are frequently observed. Hydroids present in this biotope include [Nemertesia antennina], [Halecium halecium], [Tubularia indivisa] and [Hydrallmania falcata]. Other species present include silt-tolerant sponges such as [Scypha ciliata], [Cliona celata], [Leucosolenia botryoides], and the ascidians [Clavelina lepadiformis] and [Botryllus schlosseri]. [Balanus crenatus] may be recorded occasionally on the boulder/rock surface, and the crab [Cancer pagurus] may be observed finding refuge in crevices and under boulders. More ubiquitous species present include [Asterias rubens], [Crossaster papposus], [Ophiothrix fragilis] and [Pagurus bernhardus]. Three variants of this biotope have been defined. FluCoAs.SmAs tends to have a high abundance of barnacles, which populate the rocky seabed. The second variant (FluCoAs.Paur) is characterised by abundant [Polyclinum aurantium] in addition to [F. foliacea], which often incorporates sand grains into itself, giving the crustose appearance of sandy rock nodules. Finally, FluCoAs.X is found on mixed substrata and is characterised by a dense hydroid turf growing alongside [F. foliacea] and other scour-tolerant species.
Notation A4.134
Status Valid
Status Modified 2014-01-31
Accepted Date 2014-01-31
Not Accepted Date
Has broader
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Has exact match