Description of biotope or habitat type
Hediste diversicolor in littoral mud
Habitat (physical) description
|Salinity||Reduced (18-30ppt), Variable (18-35 ppt)|
|Wave exposure||Extremely sheltered|
|Depth Band||Lower shore, Mid shore|
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'
Point data based on records in the UK Marine Recorder Snapshot.
Mud and sandy mud shores in sheltered marine inlets and estuaries subject to variable or reduced salinity. The biotope is typically found on the mid and lower shores in the upper and mid estuary. If present on the upper shore, the sediment may become firm and compacted as water drains out, though usually the biotope occurs lower on the shore and the sediment remains water saturated during low tide. An anoxic layer occurs within the upper 5 cm of the sediment. The infauna is dominated by abundant or superabundant ragworms Hediste diversicolor. Other species that occur in a significant number of samples include oligochaetes such as Heterochaeta costata and Tubificoides spp., polychaetes such as Streblospio shrubsolii and Manayunkia aestuarina, the mud shrimp Corophium volutator, and the spire shell Hydrobia ulvae.
Hed may occur on the same shores as HedMac, HedMacScr, or NhomAph. Higher up on the shore, and/or further towards the upper extreme of the estuary, Tben may occur.
Enteromorpha spp. and Ulva lactuca may form mats on the surface of the sediment during the summer months, particularly in areas of freshwater influence and/or where there is nutrient enrichment.
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - SACFOR scale||Typical abundance - (count per m2)||% of core records where taxon was recorded|
|Hediste diversicolor||45||Super abundant||1937||81-100 %|
|Streblospio shrubsolii||8||Abundant||1510||41-60 %|
|Manayunkia aestuarina||3||Common||2247||41-60 %|
|Heterochaeta costata||5||Abundant||2065||21-40 %|
|Tubificoides benedii||7||Abundant||2289||21-40 %|
|Tubificoides pseudogaster||1||Common||506||1-20 %|
|Corophium volutator||9||Common||2220||41-60 %|
|Hydrobia ulvae||1||Common||360||21-40 %|