Description of biotope or habitat type
Glycera lapidum in impoverished infralittoral mobile gravel and sand
Physical habitat description
|Salinity||Full (30-35 ppt)|
|Wave exposure||Very exposed, Exposed, Moderately exposed|
|Tidal streams||Strong (3-6 kn), Moderately strong (1-3 kn)|
|Substratum||Medium to coarse sand with some gravel|
|Depth Band||5-10 m, 10-20 m|
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.
- 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
In infralittoral mixed slightly gravelly sands on exposed open coasts impoverished communities characterised by the polychaete Glycera lapidum (agg.) may be found. Glycera lapidum is a species complex and as such some variability in identification may be found in the literature. It is also quite widespread and may occur in a variety of coarser sediments and is often present in other SCS biotopes. However, it is rarely considered a characteristic species and where this is the case it is normally due to the exclusion of other species. Consequently it is considered that habitats containing this biotope may be subject to continual or periodic sediment disturbance from wave action, which prevents the establishment of a more stable community. Other taxa include spionid polychaetes such as Spio martinensis and Spiophanes bombyx, Nephtys spp. and in some areas the bivalve Spisula elliptica. It is possible that SCS.Glap it is not a true biotope, rather an impoverished, transitional community, which in more settled conditions develops into other more stable communities.
In many cases e.g. along the East Yorkshire coast this biotope is found in shallow inshore areas facing directly into the prevailing wind and subject to considerable wave action.
Due to the variability in sediment regime at these habitats there may be high seasonal or spatial variability within this community.
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - (count per m2)||% of core records where taxon was recorded|
|Glycera lapidum||51||36||81-100 %|
|Nephtys cirrosa||7||7||41-60 %|
|Nephtys longosetosa||1||2||21-40 %|
|Spio martinensis||21||11||61-80 %|
|Spiophanes bombyx||3||12||21-40 %|
|Gastrosaccus spinifer||1||2||1-20 %|
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