Grazed, mixed Laminaria hyperborea and Laminaria saccharina on sheltered infralittoral rock

English name: Grazed, mixed Laminaria hyperborea and Laminaria saccharina on sheltered infralittoral rock

Quick facts

EUNIS habitat type code A3.3123
Bern Convention Included in a Resolution 4 habitat type at a higher level (A3)

Description (English)

Silted infralittoral rock with mixed Laminaria hyperborea and Laminaria saccharina kelp forest, intensively grazed by the echinoderm Echinus esculentus and the gastropods Gibbula cineraria and Calliostoma zizyphinum. Although both kelp species can occur in equal abundance (Common), L. hyperborea usually dominates. The grazing-resistant brown seaweed Desmarestia aculeata and Cutleria multifida may be present. A similar variety of red seaweeds to those found in the ungrazed kelp forest (A3.3121) may occur beneath the kelp canopy, but in much lower abundance. As grazing intensity increases the seaweed cover decreases - and some sites are reduced to the bare appearance of encrusting brown and coralline algae beneath the kelp canopy. The L. hyperborea stipes generally support more seaweeds than the rock beneath, including Cryptopleura ramosa, Delesseria sanguinea, Phycodrys rubens and Bonnemaisonia hamifera. The stipes may also support sometimes dense ascidians Clavelina lepadiformis and Ciona intestinalis and the echinoderm Antedon bifida. The kelp fronds are often densely covered by the hydroid Obelia geniculata. At the most intensively grazed sites even the kelp stipes are bare. Although the rock appears bare, between boulders and in crevices there are often the brittlestar Ophiothrix fragilis and the crabs Necora puber and Pagurus bernhardus. The tube-building Pomatoceros triqueter and bryozoan crusts are commonly found on any vertical surfaces.
Situation: This biotope can be found in similar conditions as units A3.3121 and A3.3122 but where the numbers of grazers present are in high enough numbers to cause substantially community impoverishment through grazing. Generally occurs on isolated rock, surrounded by sediment biotopes. Although it has been recorded from sites astride the ungrazed kelp biotopes (A3.3121 and A3.3122) it is more usually found on bedrock or boulder exposures (A4.13) adjacent to sediment seabed characterised by infaunal species.
Temporal variation: If the grazing pressure is reduced (i.e. a decrease in the number of grazing echinoderms present) the community will eventually re-establish itself as a mixed kelp forest or park (unit A3.312).

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Antedon bifida
Algae Bonnemaisonia hamifera
Invertebrates Calliostoma zizyphinum
Invertebrates Ciona intestinalis
Invertebrates Clavelina lepadiformis
Algae Cryptopleura ramosa
Algae Cutleria multifida
Algae Delesseria sanguinea
Algae Desmarestia aculeata
Invertebrates Echinus esculentus
Invertebrates Gibbula cineraria
Algae Laminaria hyperborea
Algae Laminaria saccharina
Invertebrates Necora puber
Invertebrates Obelia geniculata
Invertebrates Ophiothrix fragilis
Invertebrates Pagurus bernhardus
Algae Phycodrys rubens
Invertebrates Pomatoceros triqueter
Species scientific name English common name Species group
Antedon bifida Invertebrates
Bonnemaisonia hamifera Algae
Calliostoma zizyphinum Invertebrates
Ciona intestinalis Invertebrates
Clavelina lepadiformis Invertebrates
Cryptopleura ramosa Algae
Cutleria multifida Algae
Delesseria sanguinea Algae
Desmarestia aculeata Algae
Echinus esculentus Invertebrates
Gibbula cineraria Invertebrates
Laminaria hyperborea Algae
Laminaria saccharina Algae
Necora puber Invertebrates
Obelia geniculata Invertebrates
Ophiothrix fragilis Invertebrates
Pagurus bernhardus Invertebrates
Phycodrys rubens Algae
Pomatoceros triqueter Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 IR.LIR.K.LhypLsac.Gz Grazed, mixed <I>Laminaria hyperborea</I> and <I>Laminaria saccharina</I> on sheltered infralittoral 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 A3.3123 Grazed, mixed Laminaria hyperborea and Laminaria saccharina on sheltered infralittoral rock same
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100