Skip to Content

Marine Habitat Classification


Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Extremely exposed, Very exposed, Exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; massive boulders
Zone Infralittoral - upper
Depth Band 0-5 m, 5-10 m, 10-20 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.LhypFa <I>Laminaria hyperborea</I> forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper 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

Very exposed and exposed, but wave-surged, upper infralittoral bedrock and massive boulders characterised by a dense forest of the kelp Laminaria hyperborea with a high diversity of seaweeds and invertebrates. The shallowest kelp plants are often short or stunted, while deeper plants are taller with heavily epiphytised stipes with foliose red seaweeds such as Delesseria sanguinea, Cryptopleura ramosa or Plocamium cartilagineum or even the brown seaweed Dictyota dichotoma. Also found on the stipes or on the rock below the canopy are red seaweeds including Phycodrys rubens, Kallymenia reniformis, Callophyllis laciniata, Caryophyllia smithii, and Corallina officinalis, while encrusting coralline algae can cover any bare patches of rock. At some sites the red seaweeds can be virtually mono-specific, while at other sites show considerable variation containing a dense mixed turf of a large variety of species. The red seaweed Odonthalia dentata can be present in the north. The faunal and floral under-storey is generally rich in species due, in part, to the relatively low urchin-grazing pressure in such shallow exposed conditions. The faunal composition of this biotope varies markedly between sites, but commonly occurring are the soft coral Alcyonium digitatum and the anthozoans Sagartia elegans and Corynactis viridis. Sponges form a prominent part of the community with variable amounts of the sponges Halichondria panicea and Pachymatisma johnstonia and several other species. The crab Cancer pagurus and the starfish Asterias rubens are normally present in small numbers foraging beneath the canopy, while the sea urchins Echinus esculentus and Urticina felina graze on the seaweeds. The hydroid Obelia geniculata, the ascidian Botryllus schlosseri and the bryozoan Membranipora membranacea compete for space on the kelp, whereas the bryozoan Electra pilosa also can be found on foliose red seaweeds.

Situation

This kelp forest most commonly occurs beneath a zone of Alaria esculenta and Mytilus edulis (Ala.Myt) and may contain small patches of A. esculenta. As the force of the wave-surge diminishes with increased depth, density of the faunal turf reduces and the kelp forest or park changes to one characterised by kelp and dense red seaweeds (LhypR.Ft or LhypR.Pk). In some areas of Shetland and St Kilda the lower infralittoral zone is characterised by a park of the kelp Laminaria saccharina and/or Saccorhiza polyschides (LsacSac). Where the L. hyperborea forest continues to depths of 15 m or greater it may give way to a zone of dense foliose red algae (FoR or For.Dic).

Temporal variation

Unknown.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Pachymatisma johnstonia 1 Occasional 41-60 %
Obelia geniculata 2 Frequent 41-60 %
Alcyonium digitatum 4 Occasional 81-100 %
Urticina felina 2 Occasional 61-80 %
Sagartia elegans 4 Frequent 61-80 %
Corynactis viridis 4 Common 61-80 %
Caryophyllia smithii 1 Occasional 41-60 %
Cancer pagurus 1 Occasional 41-60 %
Necora puber 1 Occasional 41-60 %
Calliostoma zizyphinum 3 Occasional 61-80 %
Membranipora membranacea 2 Frequent 41-60 %
Electra pilosa 1 Frequent 41-60 %
Asterias rubens 4 Occasional 81-100 %
Echinus esculentus 3 Occasional 61-80 %
Botryllus schlosseri 2 Occasional 41-60 %
Corallinaceae 5 Frequent 81-100 %
Corallina officinalis 1 Occasional 41-60 %
Callophyllis laciniata 3 Occasional 61-80 %
Kallymenia reniformis 2 Occasional 41-60 %
Plocamium cartilagineum 3 Frequent 61-80 %
Cryptopleura ramosa 3 Frequent 61-80 %
Delesseria sanguinea 5 Frequent 81-100 %
Phycodrys rubens 2 Frequent 41-60 %
Dictyota dichotoma 3 Frequent 61-80 %
Laminaria hyperborea 12 Abundant 81-100 %

Similar biotopes

IR.HIR.KFaR.LhypR.Ft
L. hyperborea kelp forest with very dense foliose red seaweeds. Although encrusting fauna are present it is less conspicuous than in LhypFa.

IR.MIR.KR.Lhyp.Pk
L. hyperborea kelp park with dense foliose red seaweeds; usually found beneath the kelp forest (LhypR.Ft) but can occur beneath LhypFa where wave surge is reduced. Lacks the dense faunal turf of LhypFa.

Biotope history

Classification Habitat code
96.7 EIR.LhypFa.Ft

Photos

IR.HIR.KFAR.LhypFa Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock, Offshore North Gaulton Castle, SW Mainland, Orkney. Keith Hiscock © JNCC
IR.HIR.KFAR.LhypFa Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock, Offshore North Gaulton Castle, SW Mainland, Orkney. Keith Hiscock © JNCC
IR.HIR.KFAR.LhypFa Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock, Inshore Rora Head, NW Hoy, Orkney. Keith Hiscock © JNCC
IR.HIR.KFAR.LhypFa Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock, Inshore Rora Head, NW Hoy, Orkney. Keith Hiscock © JNCC
IR.HIR.KFAR.LhypFa Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock, Glen Bay, St Kilda. Bernard Picton © JNCC
IR.HIR.KFAR.LhypFa Laminaria hyperborea forest with a faunal cushion (sponges and polyclinids) and foliose red seaweeds on very exposed upper infralittoral rock, Glen Bay, St Kilda. Bernard Picton © JNCC

Back to top