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Marine Habitat Classification


Description of biotope or habitat type

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   Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Very exposed, Exposed, Moderately exposed
Tidal streams
Substratum Bedrock; large boulders
Zone Eulittoral - mid, Eulittoral - upper
Depth Band Mid shore, Upper shore
Other Features Also on sheltered vertical bedrock

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 LR.HLR.MusB.Sem.Sem <I>Semibalanus balanoides</I>, <I>Patella vulgata</I> and <I>Littorina</I> spp. on exposed to moderately exposed or vertical sheltered eulittoral 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'

Point data based on records in the UK Marine Recorder Snapshot.

Description

Very exposed to sheltered mid to upper eulittoral bedrock and large boulders characterised by dense barnacles Semibalanus balanoides and the limpet Patella vulgata. The community has a relatively low diversity of species though occasional cracks and crevices in the rock can provide a refuge for small individuals of the mussel Mytilus edulis, the winkle Littorina spp. and the whelk Nucella lapillus. Seaweeds are usually not found in high numbers though fissures and crevices in the bedrock can hold a sparse algae community, though patches of the red seaweed Osmundea pinnatifida can be present throughout the zone. On some shores the olive green lichen Verrucaria mucosa can be present in some abundance (Frequent). Records should not be assigned to this species impoverished biotope if there is a significant number or abundance of seaweeds.

Situation

On very exposed to exposed shores Chthamalus spp. (see Cht.Cht for geographical variation) often forms a distinct white band above a darker band of S. balanoides in the mid eulittoral zone. Alternatively, found above Sem are the black lichen Verrucaria maura dominated biotopes (Ver.Ver or Ver.B). In the lower eulittoral and the sublittoral fringe is a community dominated by the wrack Himanthalia elongata and various red seaweeds including Corallina officinalis, Mastocarpus stellatus and Osmundea pinnatifida (Him; Coff; Osm) or the mussel and barnacle dominated biotope MytB. Sem.Sem may occur on steep and vertical faces on more sheltered shores, while fucoids dominate the flatter areas (Sem.FvesR; FvesB).

Temporal variation

Periods with little scour or less severe storms can allow a seaweed community to develop creating a more diverse biotope (i.e. Fves). This is a dynamic process, which will change individual sites over time. More information is required to validate this hypothesis.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Semibalanus balanoides 35 Common 81-100 %
Patella vulgata 32 Common 61-80 %
Nucella lapillus 4 Frequent 41-60 %
Mytilus edulis 9 Occasional 61-80 %
Enteromorpha intestinalis 2 Occasional 21-40 %
Verrucaria mucosa 2 Frequent 21-40 %

Similar biotopes

LR.HLR.MusB.Sem.FvesR
Occurs on slightly less exposed shores. It has a higher abundance of S. balanoides (Abundant) and has a sparse seaweed community. The anemone Actinia equina is usually present in cracks and crevices.

LR.HLR.MusB.Cht.Cht
Usually occurs above Sem in the upper eulittoral zone. It is dominated by the barnacles Chthamalus spp. which often are favoured on very exposed shores. S. balanoides can still be present in significant numbers.

Biotope history

Classification Habitat code
97.06 ELR.BPat.Sem

Photos

LR.HLR.MUSB.Sem.Sem Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock, High Newton Snook. Eleanor Murray © JNCC
LR.HLR.MUSB.Sem.Sem Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock, High Newton Snook. Eleanor Murray © JNCC
LR.HLR.MUSB.Sem.Sem Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock, NW of Meggerland Point, Kirkandrews Bay, N Solway. Jon Davies © JNCC
LR.HLR.MUSB.Sem.Sem Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock, NW of Meggerland Point, Kirkandrews Bay, N Solway. Jon Davies © JNCC
LR.HLR.MUSB.Sem.Sem Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock, St Kilda. ANON © JNCC
LR.HLR.MUSB.Sem.Sem Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock, St Kilda. ANON © JNCC

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