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Marine Habitat Classification


Description of biotope or habitat type

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   Hediste-dominated gravelly sandy mud shores


Habitat (physical) description

Salinity Full (30-35 ppt), Reduced (18-30ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams
Substratum Gravelly sandy mud
Zone
Depth Band Lower shore, Mid shore, Strandline, 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.

Distribution of habitat LS.LMx.GvMu <I>Hediste</I>-dominated gravelly sandy mud shores

  • 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 gravelly sandy mud, subject to reduced salinity, mainly on the mid and lower shore. The infaunal community is dominated by abundant ragworms Hediste diversicolor. Other species of the infauna vary for the sub-biotopes described. They include polychaetes such as Pygospio elegans, Streblospio shrubsolii, and Manayunkia aestuarina, oligochaetes such as Heterochaeta costata and Tubificoides spp., the mud shrimp Corophium volutator, the spire shell Hydrobia ulvae, the baltic tellin Macoma balthica and the peppery furrow shell Scrobicularia plana. Sub-biotopes described in HedMx have equivalent communities in soft muddy sediments, but the sediment here is much firmer due to the gravel component. There are relatively few records in each sub-type, leading to uncertainty over the precise nature of the habitat, particularly regarding sediment type and salinity regime.

Situation

It is probable that there are broad transition areas between the sub-biotopes of HedMx, and the corresponding muddy sediment biotopes. The boundaries may be very indistinct, with the HedMx groups present in patches of gravelly mud on areas of mudflat where the main biotopes are their corresponding mud or sandy mud biotopes. Given the small number of records for each of the sub-biotopes, their spatial distribution is still uncertain.

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 62 Abundant 1406 81-100 %
Pygospio elegans 2 Common 207 21-40 %
Streblospio shrubsolii 4 Common 1099 41-60 %
Manayunkia aestuarina 1 Common 1420 21-40 %
Heterochaeta costata 3 Common 4198 21-40 %
Tubificoides benedii 3 Common 1759 41-60 %
Tubificoides pseudogaster 6 Abundant 1796 41-60 %
Corophium volutator 5 Common 2704 41-60 %
Hydrobia ulvae 2 Common 366 21-40 %
Macoma balthica 2 Common 72 21-40 %
Scrobicularia plana 2 Abundant 62 41-60 %

Similar biotopes

Not applicable or unknown.


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