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Marine Habitat Classification

Description of biotope or habitat type

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   Hediste diversicolor and Streblospio shrubsolii in littoral gravelly sandy mud

Physical habitat description

Salinity Reduced (18-30ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams
Substratum Gravelly sandy mud
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.

Distribution of habitat LS.LMx.GvMu.HedMx.Str <I>Hediste diversicolor</I> and <I>Streblospio shrubsolii</I> in littoral gravelly sandy mud

  • 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.


Extremely sheltered gravelly sandy mud, subject to variable salinity, on the mid and lower shore. The infaunal community consists of the ragworm Hediste diversicolor, Pygospio elegans, Streblospio shrubsolii, and Ampharete acutifrons, as well as oligochaetes and Corophium volutator. There are often low densities of Scrobicularia plana. Given the low sample numbers for this biotope, more records are needed to confirm the characterising species list.


It is probable that there are broad transition areas between this biotope and the corresponding muddy sediment biotope Hed.Str. The boundaries may be very indistinct, with HedMx.Str present in patches of gravelly mud on areas of mudflat, where the main biotope is Hed.Str. This biotope has been found along edges of tidal channels in the upper Stour estuary, below its equivalent mud biotope.

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
Hediste diversicolor 55 Super abundant 1719 81-100%
Oligochaeta 20 Common 1332 81-100%
Streblospio shrubsolii 14 Common 219 81-100%
Pygospio elegans 5 Common 279 41-60%
Ampharete acutifrons 3 Abundant 193 41-60%
Corophium volutator 2 Frequent 39 61-80%

Similar biotopes or habitat types

Occurs in estuarine muds, without a gravel fraction. The infauna is dominated by similar species.

Occurs in gravelly mud under more exposed conditions. The main differences in the infaunal assemblage are the abundance of Macoma balthica, and the absence of oligochaetes and a range of polychaetes including S. shrubsolii.

Occurs in muddy gravel, higher up on the shore and under less variable salinity conditions. The polychaete fauna is similar, but there are fewer oligochaetes. The bivalve infauna is more diverse, with more abundant S. plana.

Occurs in slightly more exposed gravelly sandy mud. The principal differences in the infaunal assemblage are the greater abundance of Tharyx killariensis, the abundance of oligochaetes, and the absence of S. plana.

Occurs in more sheltered gravelly sandy mud. The principal differences in the infaunal assemblage are the abundance of oligochaetes and C. volutator, and the absence of S. plana.

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