Description of biotope or habitat type
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Hediste diversicolor and Corophium volutator in littoral mud
Physical habitat description
| Salinity | Full (30-35 ppt), Reduced (18-30ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | |
| Substratum | Sandy mud |
| Zone | |
| Depth Band | Lower shore, Mid shore, Upper shore |
| Other Features |
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.
Description
Sheltered estuarine shores of sandy mud, which may become firm and compacted if present in the upper shore where there is more time for drainage between high tides. An anoxic layer is usually present within the first 5 cm of the sediment. The infauna is very sparse, usually only the ragworm Hediste diversicolor and the amphipod Corophium volutator are present in any abundance. Occasionally, oligochaetes or the spire shell Peringia ulvae may be present. Corophium multisetosum may also be found. There may be organic pollution of the sediment.
Situation
Hed.Cvol may occur on the same shores as HedMacScr, HedMac, NhomAph, and Hed.Str. Higher up on the shore, and/or further towards the head of the estuary, Hed.Ol may occur, changing to Tben at the upper extreme of the estuary.
Temporal variation
Enteromorpha spp. or 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.
Characterising species
| 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 | 48 | Abundant | 1783 | 81-100% |
| Corophium volutator | 43 | Common | 4257 | 81-100% |
Similar biotopes or habitat types
LS.LMu.UEst.Hed.Ol
Occurs under more reduced salinity conditions. The principal difference is the absence of C. volutator, and the occasional presence of Scrobicularia plana.
LS.LMu.UEst.NhomStr
Occurs in sediments with a smaller sand fraction, with a higher diversity of polychaete and oligochaete species. C. volutator is absent.
LS.LMu.MEst.HedMac
Occurs in similar physical environments. The infauna of this biotope is a lot more diverse, and dominated by a range of bivalves, including the Baltic tellin Macoma balthica, in addition to H. diversicolor and the occasionally abundant C. volutator.
LS.LMu.MEst.HedMacScr
Occurs under similar, slightly more exposed conditions. The infauna is more diverse, with higher numbers of oligochaete and polychaete species, and the peppery furrow shell S. plana.
LS.LMu.UEst.Hed.Str
Occurs under similar physical environments, slightly lower on the shore. The infauna is more diverse, with higher numbers of oligochaete and polychaete species, most notably Streblospio shrubsolii.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | LMU.Mu.HedOl (part) |
| 1995 | LMUD.HO |
