Description of biotope or habitat type
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Hediste diversicolor and Corophium volutator in littoral gravelly sandy mud
Physical habitat description
| Salinity | Variable (18-35 ppt) |
|---|---|
| Wave exposure | Extremely sheltered |
| Tidal streams | |
| Substratum | Gravelly 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
Extremely sheltered gravelly sandy mud, subject to variable or reduced salinity. The infaunal community consists of the ragworm Hediste diversicolor, Streblospio shrubsolii, Capitella capitata and Manayunkia aestuarina. Oligochaetes and Corophium volutator are abundant. Given the low sample numbers for this biotope, more records are needed to confirm the characterising species list.
Situation
It is probable that there are broad transition areas between this biotope and the corresponding muddy sediment biotope Hed.Cvol. The boundaries may be very indistinct, with HedMx.Cvol present in patches of gravelly mud on areas of mudflat, where the main biotope is Hed.Cvol.
Temporal variation
Not known.
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 |
|---|---|---|---|---|
| Corophium volutator | 27 | Frequent | 9057 | 61-80% |
| Baltidrilus costatus | 21 | Abundant | 14311 | 81-100% |
| Hediste diversicolor | 13 | Super abundant | 1542 | 81-100% |
| Tubificoides pseudogaster | 11 | Abundant | 5291 | 61-80% |
| Enchytraeidae | 8 | Abundant | 2469 | 41-60% |
| Tubificoides benedii | 8 | Abundant | 4791 | 61-80% |
| Manayunkia aestuarina | 7 | Common | 4769 | 81-100% |
| Capitella capitata | 2 | Abundant | 1089 | 41-60% |
| Streblospio shrubsolii | 2 | Common | 2576 | 41-60% |
Similar biotopes or habitat types
LS.LMu.UEst.Hed.Cvol
Occurs in estuarine muds, without a gravel fraction. The infauna is dominated by similar species.
LS.LMx.GvMu.HedMx.Mac
Occurs in gravelly mud under less saline and slightly less sheltered conditions. The main differences in the infaunal assemblage are the abundance of M. balthica, and Peringia ulvae, the absence of oligochaetes and a range of polychaetes, and lower abundances of C. volutator.
LS.LMx.GvMu.HedMx.Scr
Occurs in gravelly mud, higher up on the shore. The polychaete fauna is similar, but there are fewer oligochaetes. The bivalve infauna is more diverse, with abundant Scrobicularia plana.
LS.LMx.GvMu.HedMx.Str
Occurs in similar physical conditions. The main differences in the infaunal assemblage are fewer oligochaetes, a higher frequency of occurrence of S. shrubsolii, and the presence of occasional S. plana.