Description of biotope or habitat type
Limnodrilus hoffmeisteri, Tubifex tubifex and Gammarus spp. in low salinity infralittoral muddy sediment
Habitat (physical) description
|Wave exposure||Very sheltered, Extremely sheltered|
|Tidal streams||Weak (>1 kn), Very weak (negligible)|
|Substratum||Cohesive muddy sediment|
|Depth Band||0-5 m|
|Other Features||Very low, fluctuating salinity; possibly with a high biochemical oxygen demand|
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'
- Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat
Upper estuary muddy sediments with very low fluctuating salinity, characterised by the oligochaetes Limnodrilus hoffmeisteri and Tubifex tubifex. Other taxa may include Marenzelleria wireni, Gammarus zaddachi, Paranais litoralis and Heterochaeta costata. The biotope contains elements of both freshwater and brackish communities.
This biotope is found in the transitional zone between the freshwater and brackish environments where tidal currents are sufficiently reduced to allow the deposition of fine silt and the establishment of an infaunal community. It may be found adjacent to NeoGam away from the stronger tidal streams.
The position of this biotope in the estuary may vary seasonally depending on freshwater input (Gameson, 1982).
|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|
|Marenzelleria wireni||3||21||21-40 %|
|Limnodrilus hoffmeisteri||78||Common||1011||61-80 %|
|Tubifex tubifex||19||91||41-60 %|