Description of biotope or habitat type
Oligochaetes in littoral mobile sand
Habitat (physical) description
|Salinity||Full (30-35 ppt), Variable (18-35 ppt)|
|Wave exposure||Exposed, Moderately exposed, Sheltered, Very sheltered, Extremely sheltered|
|Depth Band||Lower shore, Mid shore, Upper shore|
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.
- 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.
A species-poor community of oligochaetes occurring in estuarine conditions where sands and gravel are associated with the lower shore river channel in estuaries. The sediment is relatively coarse and mobile due to strong river flow and subject to variable salinity. The biotope also occurs in fully marine conditions on open shores with mobile, medium to fine, usually clean, sand. Oligochaetes, including enchytraeid oligochaetes, constitute the infaunal assemblage. This biotope has been split into two sub-biotopes, based on the physical environment (a full-salinity and a variable salinity type).
Ol often occurs in variable salinity conditions, in channels of very fast flowing river mouths at the bottom of otherwise sheltered estuarine shores. In this situation, biotopes under the MEST and UEST biotope complexes may be present above the river channel. Ol also occurs on open, fully marine shores. Where it is situated on the mid shore, BarSh and/or BarSa may be present on the upper shore, and lower down on the shore, AmSco.Sco and AmSco.Pon may be found. Ol may also occur on the upper shore, with AmSco.Eur present on the mid shore, and Po.Pful or Po.Aten on the lower shore. Tal may be found on the upper shore where driftlines of wracks and debris accumulate.
Wave exposure may be higher on some beaches during winter than during the summer months, leading to the disappearance of infaunal species in winter. Where this happens, the biotope may change to BarSa. If conditions become more sheltered, seasonally or permanently, the sediment may become colonised by a greater range of species and the area may change to AmSco.
|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|