Alcyonium digitatum with Securiflustra securifrons on tide-swept moderately wave-exposed circalittoral rock

English name: Alcyonium digitatum with Securiflustra securifrons on tide-swept moderately wave-exposed circalittoral rock

Quick facts

EUNIS habitat type code A4.2143
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

This variant is typically found on the upper and vertical faces of moderately wave-exposed circalittoral bedrock subject to moderately strong to weak tidal streams. The rock surface is dominated by Alcyonium digitatum and the bryozoan Securiflustra securifrons. The rock between these species appears fairly sparse and grazed, with expanses of encrusting red algae. The sea urchin Echinus esculentus is frequently seen, and in collaboration with the light attenuating effects of depth, is probably the principal reason for the lack of algal turf. Other species found include the hydroids Abietinaria abietina, Nemertesia antennina, Thuiaria thuja, the bryozoans Cellepora pumicosa, Parasmittina trispinosa, Flustra foliacea, Alcyonidium diaphanum and other bryozoan crusts. Encrusting species such as the polychaete Pomatoceros triqueter and the barnacle Balanus balanus are frequently observed. Other species present include Asterias rubens, Antedon bifida, Ophiura albida, Ophiothrix fragilis, Caryophyllia smithii, Urticina felina, Clavelina lepadiformis, Calliostoma zizphinium and Pandalus montagui.
Situation: Above this biotope, you tend to find exposed kelp forest and park (unit A3.115). There is a tendency for slight scouring to occur in this biotope. However, if this scour increases further, for example if water movement increases, mobilising more sand, this biotope may graduate into UrtScr. In more silty sites, there is a tendency for S. securifrons to be replaced by F. foliacea as the dominant bryozoan, turning the biotope into A4.2141.
Temporal variation: Whilst the great majority of species in this variant are most likely present throughout the year, C. lepadiformis grows in spring and may show great variation in abundance from year to year.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Abietinaria abietina
Invertebrates Alcyonidium diaphanum
Invertebrates Alcyonium digitatum
Invertebrates Antedon bifida
Invertebrates Asterias rubens
Invertebrates Balanus balanus
Invertebrates Caryophyllia smithii
Invertebrates Cellepora pumicosa
Invertebrates Clavelina lepadiformis
Invertebrates Echinus esculentus
Invertebrates Flustra foliacea
Invertebrates Nemertesia antennina
Invertebrates Ophiothrix fragilis
Invertebrates Ophiura albida
Invertebrates Pandalus montagui
Invertebrates Parasmittina trispinosa
Invertebrates Pomatoceros triqueter
Invertebrates Securiflustra securifrons
Invertebrates Thuiaria thuja
Invertebrates Urticina felina
Species scientific name English common name Species group
Abietinaria abietina Invertebrates
Alcyonidium diaphanum Invertebrates
Alcyonium digitatum Invertebrates
Antedon bifida Invertebrates
Asterias rubens Invertebrates
Balanus balanus Invertebrates
Caryophyllia smithii Invertebrates
Cellepora pumicosa Invertebrates
Clavelina lepadiformis Invertebrates
Echinus esculentus Invertebrates
Flustra foliacea Invertebrates
Nemertesia antennina Invertebrates
Ophiothrix fragilis Invertebrates
Ophiura albida Invertebrates
Pandalus montagui Invertebrates
Parasmittina trispinosa Invertebrates
Pomatoceros triqueter Invertebrates
Securiflustra securifrons Invertebrates
Thuiaria thuja Invertebrates
Urticina felina Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.MCR.EcCr.FaAlCr.Sec <I>Alcyonium digitatum</I> with <I>Securiflustra securifrons</I> on tide-swept moderately wave-exposed 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 A4.2143 Alcyonium digitatum with Securiflustra securifrons on tide-swept moderately wave-exposed circalittoral rock same
EUNIS Habitat Classification 200308 A3.523 Alcyonium digitatum with Securiflustra securifrons on weakly tide-swept or scoured moderately exposed circalittoral rock same
EUNIS Habitat Classification 200202 A3.523 Alcyonium digitatum with Securiflustra securifrons on weakly tide-swept or scoured moderately exposed circalittoral rock same
EUNIS Habitat Classification 199910 A3.523 Alcyonium digitatum with Securiflustra securifrons on weakly tide-swept or scoured moderately exposed circalittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) ECR.Alc.AlcSec Alcyonium digitatum with Securiflustra securifrons on weakly tide-swept or scoured moderately exposed circalittoral rock same
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