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Marine Habitat Classification


Description of biotope or habitat type

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   Hediste diversicolor and Macoma balthica in littoral sandy mud


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 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.

Distribution of habitat LS.LMu.MEst.HedMac <I>Hediste diversicolor</I> and <I>Macoma balthica</I> in littoral 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.

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 Heterochaeta costata and the mud shrimp Corophium volutator may be abundant. The spire shell Hydrobia 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
Eteone longa 2 Common 111 21-40 %
Hediste diversicolor 17 Abundant 1168 81-100 %
Nephtys hombergii 1 27 21-40 %
Pygospio elegans 7 Common 679 61-80 %
Streblospio shrubsolii 7 Common 1084 61-80 %
Aphelochaeta marioni 3 Abundant 3457 21-40 %
Tharyx killariensis 1 Common 422 21-40 %
Capitella capitata 1 Common 483 21-40 %
Manayunkia aestuarina 4 Common 1861 41-60 %
Heterochaeta costata 1 Abundant 1082 21-40 %
Tubificoides benedii 17 Abundant 5233 81-100 %
Tubificoides pseudogaster 5 Common 4396 41-60 %
Corophium volutator 1 Abundant 3488 21-40 %
Hydrobia ulvae 6 Common 1539 61-80 %
Cerastoderma edule 2 Common 138 41-60 %
Macoma balthica 17 Common 784 81-100 %
Abra tenuis 2 Common 379 41-60 %
Mya arenaria 1 Super abundant 333 21-40 %

Similar biotopes

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.

Biotope history

Classification Habitat code
96.7 LMU.HedMac.Nhom in part
97.06 LMU.SMU.HedMac
6.95 LMUD.HM

Photos

LS.LMU.MEST.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, Havergate, Orford Ness. Roger Covey © JNCC
LS.LMU.MEST.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, Havergate, Orford Ness. Roger Covey © JNCC
LS.LMU.MEST.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, Powfoot Scar, Inner Solway. Chris Emblow © JNCC
LS.LMU.MEST.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, Powfoot Scar, Inner Solway. Chris Emblow © JNCC
LS.LMU.MEST.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, Powfoot Scar, Inner Solway. Chris Emblow © JNCC
LS.LMU.MEST.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, Powfoot Scar, Inner Solway. Chris Emblow © JNCC

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