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.

   Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed
Tidal streams
Substratum Bedrock; boulders
Zone Eulittoral - lower
Depth Band
Other Features Vertical faces on very exposed rock

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.FR.Mas <I>Mastocarpus stellatus</I> and <I>Chondrus crispus</I> on very exposed to moderately exposed lower 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

Exposed to moderately exposed lower eulittoral vertical to almost horizontal bedrock characterised by a dense turf of Mastocarpus stellatus and Chondrus crispus (either together or separately). Beneath these foliose seaweeds the rock surface is covered by encrusting coralline algae and the barnacle Semibalanus balanoides, the limpet Patella vulgata and spirorbid polychaetes. Other seaweeds including the red Lomentaria articulata and Osmundea pinnatifida, Palmaria palmata, Corallina officinalis and coralline crusts. The wrack Fucus serratus and the green seaweeds Enteromorpha intestinalis and Ulva lactuca may also be present though usually at a low abundance. Although both M. stellatus and C. crispus are widespread in the lower eulittoral and the sublittoral fringe, they occur only infrequently in a distinct band, or in large enough patches, to justify separation from Fser.R. Consequently, where only small patches of these species occur within a larger area of mixed red algal turf, then records should be assigned to more general mixed red algal turf biotope (Coff; Him). M. stellatus can be present in high abundance in a number of biotopes (Coff: Him; Fser.R etc.) found on the shore. At least one other species normally co-dominates and records should be assigned to the appropriate biotope. Caution should be taken regarding the characterising species list due to the low number of records. More information needed to validate this description.

Situation

This biotope can form a band above the main kelp zone, above Alaria esculenta (Ala) or the mussel Mytilus edulis (MytB) or within a F. serratus-red algal mosaic (Fser.R).

Temporal variation

M. stellatus is more resistant to wave action than C. crispus and may therefore dominate more exposed shores; it can dominate vertical rock at very exposed sites (e.g. Mingulay, Outer Hebrides). On more sheltered shores, especially in the south-west, M. stellatus may give way to C. crispus which has a faster growth rate.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Spirorbidae 2 Frequent 41-60 %
Semibalanus balanoides 9 Frequent 81-100 %
Patella vulgata 13 Common 81-100 %
Palmaria palmata 3 Occasional 61-80 %
Corallinaceae 4 Occasional 61-80 %
Corallina officinalis 8 Occasional 81-100 %
Chondrus crispus 1 Occasional 41-60 %
Mastocarpus stellatus 21 Abundant 81-100 %
Lomentaria articulata 4 Occasional 61-80 %
Osmundea pinnatifida 7 Occasional 81-100 %
Fucus serratus 2 Rare 61-80 %
Enteromorpha intestinalis 4 Occasional 41-60 %
Ulva lactuca 10 Occasional 81-100 %

Similar biotopes

Not applicable or unknown.

Biotope history

Classification Habitat code
6.95 LRK.RED.MAS
96.7 MLR.R.Mas

Photos

LR.HLR.FR.Mas Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock, Bird Rock, Berneray, Barra. David Connor © JNCC
LR.HLR.FR.Mas Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock, Bird Rock, Berneray, Barra. David Connor © JNCC
LR.HLR.FR.Mas Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock, Unspecified location. David Connor © JNCC
LR.HLR.FR.Mas Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock, Unspecified location. David Connor © JNCC
LR.HLR.FR.Mas Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock, Hannafore Point. Keith Hiscock © JNCC
LR.HLR.FR.Mas Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock, Hannafore Point. Keith Hiscock © JNCC

Back to top