Coralline crusts in surge gullies and scoured infralittoral rock

English name: Coralline crusts in surge gullies and scoured infralittoral rock

Quick facts

EUNIS habitat type code A3.716
Bern Convention Included in a Resolution 4 habitat type at a higher level (A3)

Description (English)

Scoured rock 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 and scour is severe, 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. Other scour-tolerant species, such as encrusting bryozoans may also be common. Crevices and cracks in the rock provide a refuge for sponge crusts such as Halichondria panicea and occasional anemones Urticina felina and Sagartia elegans. More mobile fauna is usually restricted to the echinoderms Asterias rubens and Echinus esculentus as well as the crab Cancer pagurus. Two variants have been identified: Wave-surged bedrock with coralline crust, B. crenatus and P. triqueter (A3.7161) and coralline crusts on mobile boulders in severely scoured caves (A3.7162).
Situation: Generally occurring at the base of walls in caves and gullies and on the floors of caves and gullies. 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 with extreme wave surge, 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 Asterias rubens
Invertebrates Balanus crenatus
Invertebrates Cancer pagurus
Invertebrates Echinus esculentus
Invertebrates Halichondria panicea
Invertebrates Pomatoceros triqueter
Invertebrates Sagartia elegans
Invertebrates Urticina felina
Species scientific name English common name Species group
Asterias rubens Invertebrates
Balanus crenatus Invertebrates
Cancer pagurus Invertebrates
Echinus esculentus Invertebrates
Halichondria panicea Invertebrates
Pomatoceros triqueter Invertebrates
Sagartia elegans Invertebrates
Urticina felina Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 IR.FIR.SG.CC Coralline crusts in surge gullies and scoured 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 A3.716 Coralline crusts in surge gullies and scoured infralittoral rock same
EUNIS Habitat Classification 200308 A3.415 Coralline crust in surge gullies and scoured infralittoral rock same
EUNIS Habitat Classification 200202 A3.415 Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured infralittoral rock same
EUNIS Habitat Classification 199910 A3.415 Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured infralittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) EIR.SG.CC Balanus crenatus and/or Pomatoceros triqueter with spirorbid worms and coralline crusts on severely scoured infralittoral rock same
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