Algal dominated communities in the Mediterranean infralittoral sediment

This habitat develops on infralittoral sediment covered by algae in sheltered places and where organic matter enhances macroalgal growth. Different sub-habitats that can be distinguished by the dominant species composition and the environment they colonize. These include  Caulerpa prolifera,  Acetabularia calyculus, growing on dead shells of cockles and other clams; Penicillus capitatus, usually on sediments covering dead rhizomes of Posidonia oceanica as well as Valonia aegagropila, Rytiphlaea tinctoria or Alsidium corallinum, Ulva spp., Cladophora spp. and Gracilaria spp. The habitat is also very variable depending on nutrients, sedimentation, temperature, salinity, and hydrodynamism. 

Indicators of quality:                                                                                                                            

The habitat is able to withstand severe disturbances as the environment they live in is prone to a high frequency of these events. Moreover, in some cases they are naturally adapted to high nutrient levels as they are situated on estuarine environments. In general, the subhabitat of Cystoseira barbata f. repens is more vulnerable than other subhabitats to environmental pressures. Dominance by species of Ulva, Cladophora and Gayralia usually indicate high quantities of nutrients. The presence of Syngnathidae (Hippocampus, Syngnathus) usually indicates good environmental quality. 

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats