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.
Hediste diversicolor and Streblospio shrubsolii in littoral sandy mud
Physical habitat description
| Salinity | Variable (18-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | |
| Substratum | Mud; sandy mud |
| Zone | |
| Depth Band | Lower shore, Mid 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
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 and is often associated with shallow layers of cobbles and pebbles in the sediment in the upper and mid estuary. The sediment is anoxic close to the surface and remains water saturated during low tide. The infaunal polychaete community is dominated by dense Hediste diversicolor, as well as species with a limited salinity range tolerance such as Streblospio shrubsolii and Manayunkia aestuarina. Oligochaetes, including Baltidrilus costatus and Tubificoides benedii are often abundant, and the amphipod Corophium volutator is often common.
Situation
Hed.Str may occur on the same shores as HedMacScr, HedMac, NhomAph or Hed.Cvol. 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 |
|---|---|---|---|---|
| Streblospio shrubsolii | 23 | Abundant | 3033 | 61-80% |
| Hediste diversicolor | 20 | Super abundant | 2020 | 81-100% |
| Tubificoides benedii | 18 | Abundant | 4557 | 41-60% |
| Oligochaeta | 11 | Abundant | 6592 | 21-40% |
| Manayunkia aestuarina | 7 | Common | 4526 | 61-80% |
| Corophium volutator | 6 | Common | 2897 | 41-60% |
| Baltidrilus costatus | 5 | Abundant | 2386 | 21-40% |
Similar biotopes or habitat types
LS.LMu.UEst.Hed.Ol
Occurs under more reduced salinity conditions. The infauna is a lot less diverse, dominated by H. diversicolor and oligochaetes. S. shrubsolii is absent.
LS.LMu.UEst.NhomStr
Occurs on slightly more marine, exposed shores, with a higher diversity of polychaete species, but hardly any other infauna.
LS.LMu.MEst.HedMacScr
Occurs at a greater range of shore heights on slightly more marine, exposed shores. The infauna is more diverse, most notably a range of bivalve species occur, including Scrobicularia plana.
LS.LMu.UEst.Hed.Cvol
Occurs under similar physical environments, sometimes higher on the shore. The infauna is less diverse, with lower numbers of oligochaete and polychaete species. S. shrubsolii is absent.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | LMU.MU.HedStr (part) |
