Skip to Content

Marine Habitat Classification


Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud


Habitat (physical) description

Salinity Variable (18-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered, Extremely sheltered
Tidal streams
Substratum Mud or 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.

Distribution of habitat LS.LMu.MEst.HedMacScr <I>Hediste diversicolor</I>, <I>Macoma balthica</I> and <I>Scrobicularia plana</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 shore mud or sandy mud subject to variable salinity on sheltered estuarine shores. Typically, the sediment is wet in appearance and has an anoxic layer below 1 cm depth. The surface of the mud has the distinctive 'crow's foot' pattern formed by the peppery furrow shell Scrobicularia plana. The infauna is additionally characterised by a range of polychaete and bivalve species, including the ragworm Hediste diversicolor, Pygospio elegans, Streblospio shrubsolii, Tharyx killariensis and the baltic tellin Macoma balthica. Oligochaetes, most notably Tubificoides benedii, and the spire shell Hydrobia ulvae may be abundant. Other species that sometimes occur in this biotope are the cockle Cerastoderma edule, the sand gaper Mya arenaria and the polychaetes Eteone longa and Nephtys hombergii.

Situation

HedMacScr may occur on the same shores as NhomMacStr, HedMac, NhomAph, Hed.Str and Hed.Cvol. Higher up on the shore, and/or further towards the head of the estuary, Hed.Ol may occur, changing to Tben at the upper extreme of the estuary.

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 enrichment.

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 14 Abundant 798 81-100 %
Pygospio elegans 8 Common 929 61-80 %
Streblospio shrubsolii 4 Common 392 41-60 %
Tharyx killariensis 3 Common 537 21-40 %
Oligochaeta 7 Super abundant 1677 21-40 %
Tubificoides benedii 25 Abundant 2699 41-60 %
Hydrobia ulvae 19 Abundant 4118 81-100 %
Macoma balthica 5 Common 438 61-80 %
Scrobicularia plana 5 Super abundant 250 81-100 %

Similar biotopes

LS.LMu.UEst.Hed.Ol
Tends to occur in sandier sediments, in slightly more exposed conditions, on the lower shore. There is a reduced infaunal diversity, H. diversicolor is not always present, and the cockle C. edule does not occur.

LS.LMu.UEst.NhomStr
Tends to occur lower down on slightly more exposed, marine shores, with a reduced infaunal diversity. Bivalves are absent.

LS.LMu.UEst.Hed.Str
Occurs under more sheltered estuarine conditions. The infauna is less diverse, most notably bivalve species are rare.

LS.LMu.UEst.Hed.Cvol
Tends to occur slightly higher on the shore, in more sheltered conditions. The infauna is less diverse, with lower numbers of oligochaete and polychaete species. Bivalves are virtually absent.

LS.LMu.MEst.HedMac
Occurs in similar physical conditions. S. plana is absent.

LS.LMu.MEst.NhomMacStr
Occurs further towards inner estuaries, in less saline conditions. The infauna is similar, though the ragworm H. diversicolor is often absent, and both N. hombergii and S. shrubsolii are almost always abundant. No bivalves except M. balthica occur.

Biotope history

Classification Habitat code
97.06 LMS.SMu.HedMac (part)
97.06 LMU.SMU.HedScr
6.95 LMUD.HS

Photos

LS.LMU.MEST.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud, River Leri Moorings, Dyfi estuary. Eleanor Murray © JNCC
LS.LMU.MEST.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud, River Leri Moorings, Dyfi estuary. Eleanor Murray © JNCC
LS.LMU.MEST.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud, Craig-y-Penrhyn transect, Dyfi estuary. Ian Reach © JNCC
LS.LMU.MEST.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud, Craig-y-Penrhyn transect, Dyfi estuary. Ian Reach © JNCC
LS.LMU.MEST.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud, Ynys-hir transect, Dyfi estuary. Rohan Holt © JNCC
LS.LMU.MEST.HedMacScr Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud, Ynys-hir transect, Dyfi estuary. Rohan Holt © JNCC

Back to top