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Marine Habitat Classification


Description of biotope or habitat type

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   Foliose red seaweeds on exposed lower infralittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Very exposed, Exposed, Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Bedrock; large boulders
Zone Infralittoral - lower
Depth Band 5-10 m, 10-20 m, 20-30 m
Other Features

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.

Distribution of habitat IR.HIR.KFaR.FoR Foliose red seaweeds on exposed lower infralittoral rock

  • Records used to define the biotope (core records)
  • Other records assigned to this biotope, marked as 'certain'
  • Other records assigned to this biotope, marked as 'uncertain'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.

Description

A dense turf of foliose red seaweeds on exposed or moderately exposed lower infralittoral rock, generally, at or below the lower limit of the kelp. Most of the red seaweeds are common to the kelp zone above, while the faunal component of the biotope is made up of species that are found either in the kelp zone or the animal-dominated upper circalittoral below. Foliose species commonly present include Dilsea carnosa, Hypoglossum hypoglossoides, Schottera nicaeensis, Cryptopleura ramosa and Delesseria sanguinea. The red seaweed species composition varies considerably; at some sites a single species may dominate (particularly Plocamium cartilagineum). Small filamentous red seaweeds can be found here as well. These include species such as Heterosiphonia plumosa, Brongniartella byssoides. As well as a varied red seaweed component, this biotope may also contain occasional kelp plants and patches of the brown foliose seaweed Dictyota dichotoma. Coralline crusts covers the bedrock beneath the seaweeds. The fauna generally comprises low-encrusting forms such as the tubeworms Pomatoceros spp., anthozoans including Alcyonium digitatum, Urticina felina and Caryophyllia smithii) and occasional sponge crusts such as Cliona celata, Esperiopsis fucorum, Scypha ciliata and Dysidea fragilis. More mobile fauna include the gastropod Calliostoma zizyphinum, the echinoderms Echinus esculentus as well as the starfish Asterias rubens and Marthasterias glacialis and lastly, the crab Cancer pagurus. Bryozoan crusts such as Electra pilosa can be found fronds on the foliose red seaweeds while scattered hydroids such as Nemertesia antennina form colonies on shells, cobbles and available rock. At some sites erect bryozoans Crisia spp. and Bugula spp. are present. Ascidians such as Clavelina lepadiformis and Clavelina lepadiformis may also be common. In the north the foliose red seaweed Callophyllis laciniata may occur.

Situation

This biotope is generally found at or below the lower limit of the kelp, below either kelp forest or park (LhypR.Ft and LhypR.Pk).

Temporal variation

Many of the red seaweeds, which occur in this biotope, have annual fronds, which tend to die back in the autumn and regenerate again in the spring. This produces a seasonal change in the density of the seaweed cover, which is substantially reduced over winter months and reaches its most dense between April to September.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Scypha ciliata 1 Occasional 21-40 %
Cliona celata 2 Occasional 41-60 %
Esperiopsis fucorum 1 Occasional 21-40 %
Dysidea fragilis 1 Occasional 21-40 %
Nemertesia antennina 2 Occasional 41-60 %
Alcyonium digitatum 3 Occasional 41-60 %
Urticina felina 2 Occasional 41-60 %
Caryophyllia smithii 1 Occasional 21-40 %
Pomatoceros triqueter 3 Occasional 21-40 %
Cancer pagurus 1 Rare 41-60 %
Calliostoma zizyphinum 2 Occasional 41-60 %
Electra pilosa 1 Frequent 21-40 %
Asterias rubens 7 Frequent 61-80 %
Marthasterias glacialis 2 Occasional 41-60 %
Echinus esculentus 3 Occasional 41-60 %
Clavelina lepadiformis 1 Occasional 21-40 %
Corallinaceae 7 Frequent 61-80 %
Dilsea carnosa 1 Occasional 21-40 %
Callophyllis laciniata 1 Occasional 21-40 %
Schottera nicaeensis 1 Frequent 21-40 %
Plocamium cartilagineum 8 Frequent 61-80 %
Heterosiphonia plumosa 2 Frequent 41-60 %
Cryptopleura ramosa 2 Frequent 41-60 %
Delesseria sanguinea 10 Frequent 61-80 %
Hypoglossum hypoglossoides 2 Occasional 41-60 %
Brongniartella byssoides 1 Frequent 41-60 %
Dictyota dichotoma 3 Frequent 41-60 %

Similar biotopes

IR.HIR.KFaR.FoR.Dic
This biotope occurs in similar depth and conditions as FoR but is confined to SW coasts. The abundance of the brown seaweeds Dictyopteris membranacea (Frequent) and D. dichotoma is higher (Common) with the Occasional presence of the kelps Laminaria hyperborea and Laminaria saccharina.

IR.MIR.KR.XFoR
This biotope occurs on shallow, silted infralittoral bedrock and boulders in areas of turbid water dominated by dense red seaweeds, with the notable absence of kelp. Individual species of red seaweeds such as Plocamium cartilagineum or Calliblepharis ciliata often dominate. The fauna is both less diverse and has a lower abundance.

SS.SMp.KSwSS.LsacR.CbPb
This biotope occurs on mixed, mobile substrata and is characterised by red seaweeds such as Halarachnion ligulatum, Lomentaria orcadensis, Naccaria wiggii and Compsothamnion thuyoides which thrive in these conditions.

Biotope history

Classification Habitat code
97.06 EIR.FoR
96.7 MIR.FoR

Photos

IR.HIR.KFAR.FoR Foliose red seaweeds on exposed lower infralittoral rock, SW of Pedngwinian Point, Mullian. Rohan Holt © JNCC
IR.HIR.KFAR.FoR Foliose red seaweeds on exposed lower infralittoral rock, SW of Pedngwinian Point, Mullian. Rohan Holt © JNCC
IR.HIR.KFAR.FoR Foliose red seaweeds on exposed lower infralittoral rock, North west of Rubha Aird Druimnich, Ardnamurchan Point. Paul Brazier © JNCC
IR.HIR.KFAR.FoR Foliose red seaweeds on exposed lower infralittoral rock, North west of Rubha Aird Druimnich, Ardnamurchan Point. Paul Brazier © JNCC

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