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Marine Habitat Classification


Description of biotope or habitat type

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   Pontocrates arenarius in littoral mobile sand


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Extremely exposed, Very exposed, Exposed, Moderately exposed
Tidal streams
Substratum Medium sand; fine sand
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.LSa.MoSa.AmSco.Pon <I>Pontocrates arenarius</I> in littoral mobile sand

  • 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 on the mid and lower shore on wave-exposed or moderately wave-exposed coasts of medium and fine sand, sometimes with a fraction of coarse sand, which remains damp throughout the tidal cycle and contains little organic matter. The sediment is often rippled and typically lacks an anoxic sub-surface layer. The infauna is dominated by burrowing amphipods, most notably Pontocrates arenarius, as well as Bathyporeia pelagica, Haustorius arenarius and the isopod Eurydice pulchra. The polychaete fauna is poor, dominated by Scolelepis squamata, which tolerates the exposed and mobile sediment conditions. The presence of polychaetes may be seen as coloured burrows running down from the surface of the sediment.

Situation

This biotope may be present on the lower shore, where BarSa, AmSco.Eur, or AmSco.Sco are present higher up. Where AmSco.Pon occurs on the mid shore in relatively sheltered conditions, Po may be present on the lower shore. Tal may be present where driftlines of fucoids and other debris occur on the upper shore.

Temporal variation

This biotope may change to AmSco.Eur, which is very similar in character, if P. arenarius decreases in abundance. Winter storms may reduce the number of or temporarily remove macroinvertebrates from exposed sandy beaches, with the sediment becoming re-colonised during the summer months.

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
Scolelepis 3 Abundant 22 21-40 %
Scolelepis squamata 11 Common 39 21-40 %
Pontocrates arenarius 62 Common 90 81-100 %
Bathyporeia pelagica 6 Common 37 21-40 %
Haustorius arenarius 2 Common 27 21-40 %
Eurydice pulchra 7 Frequent 49 41-60 %

Similar biotopes

LS.LSa.MoSa.AmSco.Eur
Occurs in similar physical environments, under slightly more sheltered conditions, and tending to be present higher up on the shore. Infauna is more sparse, dominated by E. pulchra, with P. arenarius absent.

LS.LSa.FiSa.Po.Pful
Occurs in more sheltered, occasionally estuarine, conditions, where sediments are more stable. The infauna is dominated by polychaete species, while burrowing amphipods occur less frequently.

LS.LSa.FiSa.Po.Aten
Occurs in more sheltered conditions. The sediments are even more stable than in the case of Po.Pful and therefore support bivalves, especially Angulus tenuis, in addition to a range of polychaete species similar to the Po.Pful assemblage. Burrowing amphipods occur less frequently than in AmSco.Pon.

Biotope history

Classification Habitat code
97.06 LGS.AP.Pon (part)
97.06 LGS.S.AEur (part)
97.06 LGS.S.AP.P (part)
6.95 LSND.AE (part)
6.95 LSND.AP (part)

Photos

LS.LSA.MOSA.AmSco.Pon Pontocrates arenarius in littoral mobile sand, Dunnerholme, Duddon estuary. Roger Covey © JNCC
LS.LSA.MOSA.AmSco.Pon Pontocrates arenarius in littoral mobile sand, Dunnerholme, Duddon estuary. Roger Covey © JNCC
LS.LSA.MOSA.AmSco.Pon Pontocrates arenarius in littoral mobile sand, Saltburn Beach. Eleanor Murray © JNCC
LS.LSA.MOSA.AmSco.Pon Pontocrates arenarius in littoral mobile sand, Saltburn Beach. Eleanor Murray © JNCC
LS.LSA.MOSA.AmSco.Pon Pontocrates arenarius in littoral mobile sand, Dinas Dinlle, Trefor. Kate Northen © JNCC
LS.LSA.MOSA.AmSco.Pon Pontocrates arenarius in littoral mobile sand, Dinas Dinlle, Trefor. Kate Northen © JNCC

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