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 Macoma balthica in littoral sandy 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 and 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
Mainly mid and lower shore sandy mud or mud in lower estuaries, sheltered bays and marine inlets, often subject to variable salinity. The main characterising species are the ragworm Hediste diversicolor, the baltic tellin Macoma balthica, and the oligochaetes Tubificoides benedii and T. pseudogaster. Further polychaetes that are often common or abundant include Pygospio elegans, Streblospio shrubsolii, Tharyx killariensis, Aphelochaeta marioni, Capitella capitata and Manayunkia aestuarina. The oligochaete Baltidrilus costatus and the mud shrimp Corophium volutator may be abundant. The spire shell Peringia ulvae is often common. Other species which occur in a significant proportion of samples include the polychaetes Eteone longa and Nephtys hombergii, and bivalves such as the cockle Cerastoderma edule and Abra tenuis. The sand gaper Mya arenaria is superabundant in about a quarter of the samples for this biotope. M. arenaria is probably present in a higher proportion of areas of this biotope, but may be missed in core samples due to its size.
Situation
HedMac may occur on the mid/lower shore of lower estuarine shores, with HedMacEte or MacAre on the upper shore. HedMacScr, Hed.Str, NhomAph, and Hed.Cvol may be present on the same shore.
Temporal variation
Enteromorpha spp. and Ulva lactuca may form mats on the surface of the mud during the summer months, particularly in areas of nutrient enrichmnent.
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 | 17 | Abundant | 1168 | 81-100% |
Macoma balthica | 17 | Common | 784 | 81-100% |
Tubificoides benedii | 17 | Abundant | 5233 | 81-100% |
Pygospio elegans | 7 | Common | 679 | 61-80% |
Streblospio shrubsolii | 7 | Common | 1084 | 61-80% |
Peringia ulvae | 6 | Common | 1539 | 61-80% |
Tubificoides pseudogaster | 5 | Common | 4396 | 41-60% |
Manayunkia aestuarina | 4 | Common | 1861 | 41-60% |
Aphelochaeta marioni | 3 | Abundant | 3457 | 21-40% |
Cerastoderma edule | 2 | Common | 138 | 41-60% |
Abra tenuis | 2 | Common | 379 | 41-60% |
Eteone longa | 2 | Common | 111 | 21-40% |
Capitella capitata | 1 | Common | 483 | 21-40% |
Corophium volutator | 1 | Abundant | 3488 | 21-40% |
Baltidrilus costatus | 1 | Abundant | 1082 | 21-40% |
Mya arenaria | 1 | Super abundant | 333 | 21-40% |
Nephtys hombergii | 1 | 27 | 21-40% | |
Tharyx killariensis | 1 | Common | 422 | 21-40% |
Similar biotopes or habitat types
LS.LSa.MuSa.MacAre
Occurs in almost fully marine conditions on the upper shore of sheltered coasts. H. diversicolor is absent, but Arenicola marina is abundant. There are fewer mollusc species, and H. ulvae is absent.
LS.LMu.UEst.Hed.Str
Occurs under less saline and slightly more sheltered conditions, further towards inner estuaries. Molluscs are very rare, with the exception of occasionally common Scrobicularia plana and H. ulvae.
LS.LMu.MEst.HedMacScr
Occurs in similar physical conditions. The most notable difference is the presence of superabundant S. plana.
LS.LMu.MEst.NhomMacStr
Tends to occur lower on the shore in slightly more exposed conditions. There is a reduced infaunal diversity, H. diversicolor is not always present, and the bivalves C. edule and M. arenaria are absent.
LS.LMu.UEst.Hed.Ol
Occurs lower on the shore in less saline and more sheltered conditions, i.e. further towards the head of estuaries. The infauna is characterised purely by H. diversicolor and oligochaets. Molluscs are virtually absent.Classification history of this biotope or habitat type
Classification version | Code |
---|---|
2015 (15.03) | LS.LMu.MEst.HedMac |
1997 (97.06) | LMU.SMU.HedMac |
1996 (6.95) | LMU.HedMac.Nhom (part) |
1995 | LMUD.HM |