EUNIS habitat classification 2017 > M - Marine benthic habitats > MB1 - Infralittoral rock > MB12 - Atlantic infralittoral rock > MB123 - Kelp and seaweed communities on sediment-affected or disturbed Atlantic infralittoral rock > MB1236 - Halidrys siliquosa and mixed kelps on tide-swept Atlantic infralittoral rock with coarse sediment

Halidrys siliquosa and mixed kelps on tide-swept Atlantic infralittoral rock with coarse sediment

Quick facts

EUNIS habitat type code MB1236
Relation to Resolution 4 habitat type (used for designation of Emerald sites)

Description (English)

Tide-swept boulders and cobbles, often with a mobile component to the substrata (pebbles, gravel and sand), characterised by dense stands of the brown seaweed Halidrys siliquosa. It is can be mixed with the foliose brown seaweed Dictyota dichotoma and kelp such as Laminaria saccharina and Laminaria hyperborea. Below the canopy is an undergrowth of red seaweeds that are tolerant of sand-scour such as Phyllophora crispa, Phyllophora pseudoceranoides, Rhodomela confervoides, Corallina officinalis and Chondrus crispus. Other red seaweeds such as Plocamium cartilagineum, Calliblepharis ciliata, Cryptopleura ramosa, Delesseria sanguinea, Heterosiphonia plumosa, Dilsea carnosa, Hypoglossum hypoglossoides and Brongniartella byssoides may be locally abundant, particularly in the summer months. There may be a rich epibiota on H. siliquosa, including the hydroid Aglaophenia pluma, ascidians such as Botryllus schlosseri. There is generally a sparse faunal component colonising the boulders and cobbles, comprising the tube-building polychaete Pomatoceros triqueter, the crab Cancer pagurus, the starfish Asterias rubens, the gastropod Gibbula cineraria and the sea anthozoan Urticina felina. The bryozoan Electra pilosa can form colonies on the kelp.
Situation: This unit can occur below the tide-swept Laminaria digitata zone of the sublittoral fringe bedrock or boulders (unit MB1-21E). Less stable substrata of boulders, cobbles or pebbles may support kelp and Chorda filum in the shallows (MB1-233) or dense ephemeral seaweeds (unit MA1-23). Sand-influenced rocky outcrops in deeper water may support a Flustra foliacea community (MC1-216). This biotope is widespread and is found on the open coast in Wales, the south-west and the English Channel as well as more sheltered tidal rapids in the Scottish sealochs. It can form extensive forests or parks in certain areas (Dorset, Sarns). In Wales, the south-west and west of England the red seaweeds Spyridia filamentosa and Halarachnion ligulatum and brown seaweeds Dictyopteris membranacea and Taonia atomaria are frequent. In Scotland, kelp occur at a greater proportion of sites, solitary ascidians such as Ascidiella spp. are more common and the featherstar Antedon bifida and brittlestars Ophiothrix fragilis are found.
Temporal variation: Higher diversity of red seaweeds during the summer.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Algae Brongniartella byssoides
Algae Calliblepharis ciliata
Algae Chondrus crispus
Algae Corallina officinalis
Algae Cryptopleura ramosa
Algae Delesseria sanguinea
Algae Dictyota dichotoma
Algae Dilsea carnosa
Algae Halarachnion ligulatum
Algae Heterosiphonia plumosa
Algae Hypoglossum hypoglossoides
Algae Laminaria digitata
Algae Laminaria hyperborea
Algae Laminaria saccharina
Algae Phyllophora crispa
Algae Plocamium cartilagineum
Algae Rhodomela confervoides
Algae Spyridia filamentosa
Algae Taonia atomaria
Invertebrates Aglaophenia pluma
Invertebrates Antedon bifida
Invertebrates Asterias rubens
Invertebrates Botryllus schlosseri
Invertebrates Cancer pagurus
Invertebrates Flustra foliacea
Invertebrates Gibbula cineraria
Invertebrates Ophiothrix fragilis
Invertebrates Pomatoceros triqueter
Species scientific name English common name Species group
Brongniartella byssoides Algae
Calliblepharis ciliata Algae
Chondrus crispus Algae
Corallina officinalis Algae
Cryptopleura ramosa Algae
Delesseria sanguinea Algae
Dictyota dichotoma Algae
Dilsea carnosa Algae
Halarachnion ligulatum Algae
Heterosiphonia plumosa Algae
Hypoglossum hypoglossoides Algae
Laminaria digitata Algae
Laminaria hyperborea Algae
Laminaria saccharina Algae
Phyllophora crispa Algae
Plocamium cartilagineum Algae
Rhodomela confervoides Algae
Spyridia filamentosa Algae
Taonia atomaria Algae
Aglaophenia pluma Invertebrates
Antedon bifida Invertebrates
Asterias rubens Invertebrates
Botryllus schlosseri Invertebrates
Cancer pagurus Invertebrates
Flustra foliacea Invertebrates
Gibbula cineraria Invertebrates
Ophiothrix fragilis Invertebrates
Pomatoceros triqueter Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 2007 (revised descriptions 2012) A3.126 Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment same
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type Comment
EUNIS Habitat Classification 200410 A3.126 Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment same
EUNIS Habitat Classification 200308 A3.236 Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment same
EUNIS Habitat Classification 200202 A3.236 Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment same
EUNIS Habitat Classification 199910 A3.236 Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment same
MNCR BioMar 97.06 (Britain & Ireland) MIR.SedK.HalXK Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment same
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100