Identity:

These biocenoses consist mainly of detritus-feeding species which draw their nourishment from decaying vegetation and miscellaneous debris caught up in the shingle. It is characterised by two crustaceans, the amphipod Gammarus olivii and the isopod Sphaeroma serratum. These communities are exposed to alternating water submersion and emersion because of variations in the water level, and they are frequently moistened by wavelets.