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Marine Habitat Classification


Description of biotope or habitat type

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   Fucus serratus and piddocks on lower eulittoral soft rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams
Substratum Bedrock; boulders
Zone Eulittoral - lower
Depth Band Lower shore, Mid shore
Other Features Soft rock (chalk)

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.MLR.BF.Fser.Pid <I>Fucus serratus</I> and piddocks on lower eulittoral soft 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

The lower eulittoral zone on soft rock shores (e.g. chalk) characterised by the wrack Fucus serratus. Much of the community associated with this biotope is the same as the biotope Fserr.FS, but certain taxa are specific to the soft underlying substrata. Rock-boring fauna including the piddocks Barnea spp., Pholas dactylus and Hiatella arctica can occur in dense aggregations. Burrowing polychaetes such as Polydora spp. can also occur in high numbers only visible due to their long, slender palps waving in the water as they occupy holes in the top few centimetres of the rock. A dense red algal turf occurs beneath the F. serratus and includes Gelidium pusillum, Osmundea pinnatifida, Palmaria palmata, Lomentaria articulata and Rhodothamniella floridula, but also calcareous algae such as Corallina officinalis and coralline crusts including the red-violet encrusting algae Phymatolithon lenormandii are present. Infaunal taxa such as various amphipods may be common amongst the seaweeds. The empty piddock holes may provide a refuge for species such as the anemone Actinia equina and the mussel Mytilus edulis while the barnacle Semibalanus balanoides, the limpet Patella vulgata can be present on the surface of the soft rock. The whelk Nucella lapillus, the winkles Littorina littorea and Littorina mariae and the top shell Gibbula cineraria are all present on the soft rock among the seaweeds. The high number of characterising species is partly caused by the low number of records used to define this biotope. The high % frequency of occurrence is partly a result of the low number of records. More data is needed to validate this biotope description.

Situation

This biotope usually occurs immediately below either a Fucus vesiculosus-barnacle mosaic (FvesB) or a Mytilus edulis and piddocks-dominated biotope (MytPid) on moderately exposed shores or a dense canopy of F. vesiculosus (Fves) or Ascophyllum nodosum (Asc.FS) on sheltered shores. The littoral fringe below are on moderately exposed shores dominated by the kelp Laminaria digitata (Ldig.Pid), while the kelp Laminaria saccharina may co-dominate on sheltered shores (Lsac.Ldig; Lsac.Ft).

Temporal variation

Unknown, but probably as Fserr.FS

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Actinia equina 2 Rare 61-80 %
Polydora 7 Abundant 61-80 %
Pomatoceros lamarcki 2 Occasional 61-80 %
Semibalanus balanoides 5 Frequent 61-80 %
Amphipoda 4 Common 61-80 %
Gibbula cineraria 1 Occasional 41-60 %
Patella vulgata 5 Occasional 81-100 %
Littorina littorea 4 Occasional 61-80 %
Littorina mariae 4 Occasional 81-100 %
Nucella lapillus 1 41-60 %
Mytilus edulis 1 41-60 %
Hiatella arctica 2 Occasional 61-80 %
Pholas dactylus 2 Common 61-80 %
Gelidium pusillum 2 Occasional 61-80 %
Palmaria palmata 2 Occasional 61-80 %
Rhodothamniella floridula 1 61-80 %
Corallinaceae 3 Common 61-80 %
Corallina officinalis 5 Frequent 61-80 %
Phymatolithon lenormandii 5 Common 61-80 %
Chondrus crispus 3 Frequent 61-80 %
Lomentaria articulata 2 Occasional 41-60 %
Osmundea pinnatifida 5 Common 61-80 %
Fucus serratus 17 Abundant 81-100 %
Ulva lactuca 3 Occasional 61-80 %

Similar biotopes

LR.LLR.F.Fserr.FS
Occurs on hard bedrock. Has a similar species composition, but lacks the rock-boring piddocks such as H. arctica and P. dactylus or burrowing polychaetes such as Polydora spp.

LR.MLR.BF.Fser.R
Occurs on bedrock, but otherwise similar physical conditions. Has a similar species composition, but lack the rock-boring piddocks such as H. arctica and P. dactylus or burrowing polychaetes such as Polydora spp. The encrusting calcareous red algae Phymatolithon lenormandii are also missing.

Biotope history

Classification Habitat code
6.95 LRK.FSE.PID

Photos

LR.MLR.BF.Fser.Pid Fucus serratus and piddocks on lower eulittoral soft rock, Birling Gap. David George © JNCC
LR.MLR.BF.Fser.Pid Fucus serratus and piddocks on lower eulittoral soft rock, Birling Gap. David George © JNCC

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