EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A1 - Littoral rock and other hard substrata > A1.4 - Features of littoral rock > A1.44 - Communities of littoral caves and overhangs > A1.446 - Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock and in cave entrances

Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock and in cave entrances

English name: Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock and in cave entrances

Quick facts

EUNIS habitat type code A1.446
Bern Convention Included in a Resolution 4 habitat type at a higher level (A1.44)

Description (English)

Overhanging shaded bedrock on the open lower shore and at the entrance to inner reaches of caves (where light availability permits), which is not subject to appreciable wave-surge, characterised by a shade-tolerant red seaweed community. It includes foliose species such as Plumaria plumosa, Palmaria palmata, Mastocarpus stellatus, Membranoptera alata and Osmundea pinnatifida, but Lomentaria articulata and coralline crusts are usually present as well. The foliose green seaweed Ulva lactuca can be present. The rock surface often supports dense populations of calcareous tube-forming polychaetes Spirorbis spp. and Pomatoceros spp., while sponges such as Grantia compressa, Halichondria panicea and Hymeniacidon perleve can be common. The hydroid Dynamena pumila (normally found on fucoids) hangs in distinct form from overhanging rock. Colonies of the ascidian Botryllus schlosseri can be found on the rock, along with the mussel Mytilus edulis and the barnacles Semibalanus balanoides and Balanus perforatus (the latter may occur at high densities in the south and west), while the anemone Actinia equina thrives in the permanently damp pits and crevices. The whelk Nucella lapillus can be found among the barnacles and mussels, preying on them. The long list of characterising species is partly due to the difference in the species composition and does not solely reflect a high species richness.
Situation: On overhangs, this biotope is generally found above the A1.447 biotope, where there is more light available. In cave environments, this unit may be found at the entrance to and inner reaches of the cave, extending from the lower walls (above the A1.447 biotope) to the upper walls (depending on the height of the cave). Further into the cave where less light is available the ascidian Dendrodoa grossularia can be abundant (unit A1.4461).

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Algae Lomentaria articulata
Algae Membranoptera alata
Algae Osmundea pinnatifida
Algae Palmaria palmata
Algae Plumaria plumosa
Algae Ulva lactuca
Invertebrates Actinia equina
Invertebrates Balanus perforatus
Invertebrates Botryllus schlosseri
Invertebrates Dendrodoa grossularia
Invertebrates Dynamena pumila
Invertebrates Grantia compressa
Invertebrates Halichondria panicea
Invertebrates Mytilus edulis
Invertebrates Nucella lapillus
Invertebrates Semibalanus balanoides
Species scientific name English common name Species group
Lomentaria articulata Algae
Membranoptera alata Algae
Osmundea pinnatifida Algae
Palmaria palmata Algae
Plumaria plumosa Algae
Ulva lactuca Algae
Actinia equina Invertebrates
Balanus perforatus Invertebrates
Botryllus schlosseri Invertebrates
Dendrodoa grossularia Invertebrates
Dynamena pumila Invertebrates
Grantia compressa Invertebrates
Halichondria panicea Invertebrates
Mytilus edulis Invertebrates
Nucella lapillus Dog whelk Invertebrates
Semibalanus balanoides Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 LR.FLR.CvOv.SpR Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock and in cave entrances source
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A1.446 Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock and in cave entrances same
EUNIS Habitat Classification 200308 A1.612 Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock and in cave entrances same
EUNIS Habitat Classification 200202 A1.612 Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock same
EUNIS Habitat Classification 199910 A1.612 Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock same
MNCR BioMar 97.06 (Britain & Ireland) LR.Ov.SR Sponges and shade-tolerant red seaweeds on overhanging lower eulittoral bedrock same
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