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LS.LMu.MEst.HedMac
Hediste diversicolor and Macoma balthica in littoral sandy mud

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Habitat (physical) description

Distribution

 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.

Previous code

This biotope occurred in previous versions of the classification as:
LMU.SMU.HedMac - Version: 97.06
LMU.HedMac.Nhom in part - Version: 96.7
LMUD.HM - Version: 6.95

Distribution of habitat LS.LMu.MEst.HedMac  Hediste diversicolor and Macoma balthica in littoral sandy mud
Distribution of habitat LS.LMu.MEst.HedMac Hediste diversicolor and Macoma balthica in littoral sandy mud, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope 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.

Similar biotopes

LS.LSa.MuSa.MacAreOccurs 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.StrOccurs 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.HedMacScrOccurs in similar physical conditions. The most notable difference is the presence of superabundant S. plana.
LS.LMu.MEst.NhomMacStrTends 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.OlOccurs 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.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity Abundance (no.2)
Eteone longa C 2 111
Hediste diversicolor A 17 1168
Nephtys hombergii P 1 27
Pygospio elegans C 7 679
Streblospio shrubsolii C 7 1084
Aphelochaeta marioni A 3 3457
Tharyx killariensis C 1 422
Capitella capitata C 1 483
Manayunkia aestuarina C 4 1861
Heterochaeta costata A 1 1082
Tubificoides benedii A 17 5233
Tubificoides pseudogaster C 5 4396
Corophium volutator A 1 3488
Hydrobia ulvae C 6 1539
Cerastoderma edule C 2 138
Macoma balthica C 17 784
Abra tenuis C 2 379
Mya arenaria S 1 333

Example photographs of biotope


Upper shore mud with Hediste holes and tracks., Havergate, Orford Ness., Roger Covey, © JNCC Sediment with Hydrobia sp in midshore., Powfoot Scar, Inner Solway., Chris Emblow, © JNCC Rich sediment with bivalves and polychaetes, showing Mya siphon holes., Powfoot Scar, Inner Solway., Chris Emblow, © JNCC
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Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901