Flustra foliacea and colonial ascidians on tide-swept exposed circalittoral mixed substrata

English name: Flustra foliacea and colonial ascidians on tide-swept exposed circalittoral mixed substrata

Quick facts

EUNIS habitat type code A4.1343
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

This variant is typically found on very exposed to moderately exposed, circalittoral mixed substrata subject to moderately strong tidal streams. It most frequently occurs between 10m and 20m water depth. This variant is characterised by a dense hydroid and Flustra foliacea turf, along with other scour-tolerant species, growing on the more stable boulders and cobbles which overlie coarse muddy sand and gravel. Although Nemertesia antennina is the dominant species within the hydroid turf, other species such as Halecium halecinum, Nemertesia ramosa and Hydrallmania falcata may also be present. Other bryozoans found amongst the hydroid and Flustra turf include Cellepora pumicosa, Bugula flabellata, Bugula turbinata, and a crisiid turf. Encrusting red algae, the polychaete Pomatoceros triqueter and barnacles such as Balanus crenatus may be found on the smaller cobbles and pebbles, which may become mobile during extreme storms. Echinoderms such as Asterias rubens and Ophiothrix fragilis may be present on the boulders, or the coarse sediment in between. On the larger, more stable boulders, isolated sponge communities may develop, with species such as Scypha ciliata, Dysidea fragilis, Hemimycale columella, Esperiopsis fucorum and Stelligera rigida. In addition, small Alcyonium digitatum, various ascidians (Clavelina lepadiformis, Botryllus schlosseri), Pododesmus patelliformis and top shells (Calliostoma zizyphinum, Gibbula cineraria) may colonise the upper faces and vertical sides of larger boulders. At some shallower sites, the foliose red algae Hypoglossum hypoglossoides may be found on the tops of larger boulders. Within the coarse sediment underlying these boulders and cobbles, anemones such as Cerianthus lloydii and Urticina felina may be recorded. Under-boulder fauna typically consists of terebellid worms, and crabs such as Pisidia longicornis and Cancer pagurus.
Situation: This variant is found in wave-exposed locations, resulting in kelp forest in the infralittoral zone being dominated by Alaria esculentus and Laminaria hyperborea. When the substratum becomes rockier, this biotope will graduate into the variant A4.1342.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Alcyonium digitatum
Invertebrates Asterias rubens
Invertebrates Balanus crenatus
Invertebrates Botryllus schlosseri
Invertebrates Bugula flabellata
Invertebrates Bugula turbinata
Invertebrates Calliostoma zizyphinum
Invertebrates Cancer pagurus
Invertebrates Cellepora pumicosa
Invertebrates Clavelina lepadiformis
Invertebrates Dysidea fragilis
Invertebrates Esperiopsis fucorum
Invertebrates Flustra foliacea
Invertebrates Gibbula cineraria
Invertebrates Hemimycale columella
Invertebrates Hydrallmania falcata
Algae Hypoglossum hypoglossoides
Algae Laminaria hyperborea
Invertebrates Nemertesia antennina
Invertebrates Nemertesia ramosa
Invertebrates Ophiothrix fragilis
Invertebrates Pisidia longicornis
Invertebrates Pododesmus patelliformis
Invertebrates Pomatoceros triqueter
Invertebrates Stelligera rigida
Invertebrates Urticina felina
Species scientific name English common name Species group
Alcyonium digitatum Invertebrates
Asterias rubens Invertebrates
Balanus crenatus Invertebrates
Botryllus schlosseri Invertebrates
Bugula flabellata Invertebrates
Bugula turbinata Invertebrates
Calliostoma zizyphinum Invertebrates
Cancer pagurus Invertebrates
Cellepora pumicosa Invertebrates
Clavelina lepadiformis Invertebrates
Dysidea fragilis Invertebrates
Esperiopsis fucorum Invertebrates
Flustra foliacea Invertebrates
Gibbula cineraria Invertebrates
Hemimycale columella Invertebrates
Hydrallmania falcata Invertebrates
Hypoglossum hypoglossoides Algae
Laminaria hyperborea Algae
Nemertesia antennina Invertebrates
Nemertesia ramosa Invertebrates
Ophiothrix fragilis Invertebrates
Pisidia longicornis Invertebrates
Pododesmus patelliformis Invertebrates
Pomatoceros triqueter Invertebrates
Stelligera rigida Invertebrates
Urticina felina Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.HCR.XFa.FluCoAs.X <I>Flustra foliacea</I> and colonial ascidians on tide-swept exposed circalittoral mixed substrata 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 A4.1343 Flustra foliacea and colonial ascidians on tide-swept exposed circalittoral mixed substrata same
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