EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A3 - Infralittoral rock and other hard substrata > A3.7 - Features of infralittoral rock > A3.71 - Robust faunal cushions and crusts in surge gullies and caves > A3.716 - Coralline crusts in surge gullies and scoured infralittoral rock > A3.7161 - Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock

Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock

English name: Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock

Quick facts

EUNIS habitat type code A3.7161
Bern Convention Included in a Resolution 4 habitat type at a higher level (A3)

Description (English)

Severely scoured bedrock in wave-surged caves, tunnels or gullies often looks rather bare, and may be characterised by a limited scour-tolerant fauna of Balanus crenatus and/or Pomatoceros triqueter with spirorbid polychaetes. In areas where sufficient light is available, encrusting coralline algae and non-calcareous crusts cover the rock surface, giving a pink appearance. This biotope most commonly occurs at the bottom of walls in caves and gullies, where abrasion by cobbles and stones is severe, especially during winter. In some gullies, extreme scouring and abrasion produces a narrow band of bare coralline algal crust at the very bottom of the walls, with a band of P. triqueter and or B. crenatus immediately above. In some caves extreme wave surge at the back of the cave leads to a zone of this biotope which may also be dominated solely by sprorbids or by the barnacle Verruca stroemia. Other scour-tolerant species, such as encrusting bryozoans may also be common. Crevices and cracks in the rock provide a refuge for sponge crusts, small Mytilus edulis and occasional Actinia equina, Urticina felina and Sagartia elegans. More mobile fauna is usually restricted to the echinoderm Asterias rubens and the crab Cancer pagurus. During periods of relative stability in the summer, small quantities of foliose red seaweeds and opportunistic kelps may occur where sufficient light is available; the seaweeds however do not dominate (compare with A3.711).
Situation: Generally occurs at the base of walls in caves and gullies, but in extreme surge may occur as a zone at the back of caves. Immediately above this zone a variety of biotopes may occur depending on the proximity to the cave/gully entrance. Typically sponge crusts and ascidians with a hydroid-bryozoan turf will occur in the outer to mid section (units A3.712, A3.713); sponge crusts and dense ascidians in the outer to rear section (A3.714); and low-growing sponge crusts at the rear of caves (A3.715). At some sites, A3.7161 can form a zone towards the rear of the cave, beyond the sponge crust zone.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Actinia equina
Invertebrates Asterias rubens
Invertebrates Balanus crenatus
Invertebrates Cancer pagurus
Invertebrates Mytilus edulis
Invertebrates Pomatoceros triqueter
Invertebrates Sagartia elegans
Invertebrates Urticina felina
Invertebrates Verruca stroemia
Species scientific name English common name Species group
Actinia equina Invertebrates
Asterias rubens Invertebrates
Balanus crenatus Invertebrates
Cancer pagurus Invertebrates
Mytilus edulis Invertebrates
Pomatoceros triqueter Invertebrates
Sagartia elegans Invertebrates
Urticina felina Invertebrates
Verruca stroemia Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 IR.FIR.SG.CC.BalPom <I>Balanus crenatus</I> and/or <I>Pomatoceros triqueter</I> with spirorbid worms and coralline crusts on severely-scoured vertical 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 A3.7161 Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock same
EUNIS Habitat Classification 200308 A3.4151 Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock same
EUNIS Habitat Classification 200202 A3.4151 Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock same
EUNIS Habitat Classification 199910 A3.4151 Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) EIR.SG.CC.BalPom Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured vertical infralittoral rock same
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