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

Robust faunal cushions and crusts in surge gullies and caves

English name: Robust faunal cushions and crusts in surge gullies and caves

Quick facts

EUNIS habitat type code A3.71
Bern Convention Included in a Resolution 4 habitat type at a higher level (A3)
Relation to Annex I habitat types (EU Habitats Directive)

Description (English)

Infralittoral rocky habitats subject to strong wave surge conditions, as found in surge gullies and shallow caves, and typically colonised by faunal communities of encrusting or cushion sponges, colonial ascidians, short turf-forming bryozoans, anthozoans, barnacles and, where there is sufficient light, red seaweeds. These features usually consist of vertical bedrock walls, occasionally with overhanging faces, and support communities which reflect the degree of wave surge they are subject to, and any scour from mobile substrata on the cave/gully floors. The larger cave and gully systems, such as found in Shetland, Orkney, the Western Isles and St Kilda, typically show a marked zonation from the entrance to the rear of the gully/cave as wave surge increases and light reduces. This is reflected in communities of anthozoans, ascidians, bryozoans and red seaweeds near the entrance, leading to sponge crust-dominated communities and finally barnacle and spirorbid worm communities in the most severe surge conditions. Gully/cave floors usually have mobile boulders, cobbles, pebbles or coarse sediment. The mobile nature of the gully/cave floors leads to communities of encrusting species, tolerant of scour and abrasion or fast summer-growing ephemeral species. The lower zone of the gully side walls are also often scoured, and typically colonised by coralline crusts and barnacles.
Situation: On open rocky coasts with moderate or greater wave action.
Temporal variation: Unknown, although winter storms likly to yield scouring on gully/cave walls; some ephemeral growth likely in calmer summer months.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Not available

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 IR.FIR.SG Infralittoral surge gullies and caves source
Palaearctic Habitat Classification 200112 11.26 Sublittoral cave communities wider
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 A3.71 Robust faunal cushions and crusts in surge gullies and caves same
EUNIS Habitat Classification 200308 A3.41 Robust faunal cushions and crusts in surge gullies and caves same
EUNIS Habitat Classification 200202 A3.41 Robust fauna on infralittoral surge gullies and cave walls same
EUNIS Habitat Classification 199910 A3.41 Robust fauna on infralittoral surge gullies and cave walls same
EUNIS Habitat Classification 199811 A3.13 Robust faunal cushions and crusts in surge gullies same
EUNIS Habitat Classification 199712 A3.14 Sponge encrustations in surge gullies same
Palaearctic Habitat Classification 199905 11.26 Part of Sublittoral cave communities wider
MNCR BioMar 97.06 (Britain & Ireland) EIR.SG Robust faunal cushions and crusts (surge gullies and caves) same
MNCR BioMar 96.7 (Britain & Ireland) EIR.SG   narrower
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