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IR.FIR.SG
Infralittoral surge gullies and caves

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt) 
 Wave exposure: Extremely exposed, Very exposed, Exposed, Moderately exposed 
 Tidal streams: Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) 
 Substratum: Bedrock (boulders, cobbles, pebbles or coarse sediment in gully floors) 
 Zone: Infralittoral, Sublittoral fringe 
 Depth Band: 0-5 m, 5-10 m, 10-20 m 
 Other Features: Wave surged gullies or caves; vertical (and overhanging rock) 

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Previous code

This biotope occurred in previous versions of the classification as:
EIR.SG - Version: 97.06

Distribution of habitat IR.FIR.SG  Infralittoral surge gullies and caves
Distribution of habitat IR.FIR.SG Infralittoral surge gullies and caves, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

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.

Similar biotopes

IR.HIR.KFaRHas a more prominant kelp and seaweed component.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity
Clathrina coriacea F 6
Pachymatisma johnstonia O 2
Halichondria panicea F 5
Esperiopsis fucorum O 1
Myxilla incrustans O 1
Porifera indet crusts O 2
Tubularia indivisa O 3
Alcyonium digitatum O 2
Urticina felina O 4
Metridium senile F 1
Sagartia elegans O 5
Corynactis viridis F 2
Pomatoceros triqueter O 2
Balanus crenatus F 7
Cancer pagurus O 5
Calliostoma zizyphinum O 1
Bryozoa indet crusts F 1
Henricia O 1
Asterias rubens O 3
Echinus esculentus O 1
Polyclinum aurantium F 1
Didemnidae F 2
Dendrodoa grossularia C 5
Botryllus schlosseri O 2
Corallinaceae F 7

Example photographs of biotope

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Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901