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Marine Habitat Classification


Description of biotope or habitat type

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   Sponges, shade-tolerant red seaweeds and Dendrodoa grossularia on wave-surged overhanging lower eulittoral bedrock and caves


Habitat (physical) description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Exposed, Moderately exposed, Sheltered
Tidal streams
Substratum Bedrock
Zone Eulittoral - lower
Depth Band
Other Features Overhanging rock and caves

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.FLR.CvOv.SpR.Den Sponges, shade-tolerant red seaweeds and <I>Dendrodoa grossularia</I> on wave-surged overhanging lower eulittoral bedrock and caves

  • 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

Overhanging bedrock on the lower shore, at cave entrances, to and on inner walls of caves, subject to wave surge and low light levels, and characterised by a high density of small groups of the solitary ascidian Dendrodoa grossularia. The sponges Grantia compressa, Halichondria panicea and Hymeniacidon perleve are common on the rock surface, while the hydroid Dynamena pumila (normally found on fucoids) hangs in distinct form from overhanging rock. Found on the rock surface are the calcareous tube-forming polychaetes Spirorbis spp. and Pomatoceros spp. along with the barnacles Semibalanus balanoides. The anemone Actinia equina thrives in the permanently damp pits and crevices. Where sufficient light is available a sparse community of shade-tolerant red seaweeds. These include Membranoptera alata, Lomentaria articulata, Audouinella spp. and coralline crusts.

Situation

This biotope is found on lower shore overhangs and on the entrances and inner walls of lower shore caves, and usually dominates the available habitat. It is generally found above the BarCv biotope and may extend to the upper walls of caves.

Temporal variation

Some variation in the species composition of the individual caves must be expected depending on local conditions.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Grantia compressa 10 Occasional 61-80 %
Halichondria panicea 19 Frequent 81-100 %
Hymeniacidon perleve 2 Occasional 41-60 %
Dynamena pumila 4 Frequent 41-60 %
Actinia equina 2 Occasional 41-60 %
Spirorbidae 2 Common 21-40 %
Semibalanus balanoides 4 Common 41-60 %
Dendrodoa grossularia 34 Abundant 81-100 %
Audouinella 7 Common 41-60 %
Corallinaceae 5 Occasional 41-60 %
Lomentaria articulata 2 Occasional 21-40 %
Membranoptera alata 2 Rare 41-60 %

Similar biotopes

LR.FLR.CvOv.SpR
Occurs at localities with more available light. The ascidian Dendrodoa grossularia does not occur and red and brown seaweeds are usually present at higher frequency and at a higher abundance.

LR.FLR.CvOv.SpByAs
Occurs in similar physical conditions. SpByAs lacks the red seaweed community, except for a few individuals on the edge of overhangs.

Biotope history

Classification Habitat code
6.95 LRK.RSP
96.7 MLR.S.R

Photos

LR.FLR.CVOV.SpR.Den Sponges, shade-tolerant red seaweeds and Dendrodoa grossularia on wave-surged overhanging lower eulittoral bedrock and caves, Rumbling Kern, Dunstanburgh & Craster. Jon Davies © JNCC
LR.FLR.CVOV.SpR.Den Sponges, shade-tolerant red seaweeds and Dendrodoa grossularia on wave-surged overhanging lower eulittoral bedrock and caves, Rumbling Kern, Dunstanburgh & Craster. Jon Davies © JNCC

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