MA1-54 - Biocénose de la roche du médiolittoral inférieur en Méditerranée (EUNIS 2022)

MA1-54 - Biocénose de la roche du médiolittoral inférieur en Méditerranée

Biocenosis of Mediterranean lower mediolittoral rock

MA1-53 - Biocénose de la roche du médiolittoral supérieur en Méditerranée

MA1-55 - Biocénose des grottes et surplombs du médiolittoral en Méditerranée

Classification des habitats EUNIS 2022

Descriptif de l'habitat

The lower horizon of the mediolittoral rock results from the coming together of three essential factors: presence of waves, irregular variations in atmospheric pressure, and wind and tide when present. The constant humectation, greater than in the higher horizon, is the dominant factor, followed by light. Its size depends on the morphology of the substratum and – especially – on the intensity of the humectation, and may vary from several centimeters to one meter.
This habitat, particularly characterised by the presence of crust-forming melobesiae algae, varies according to the nature of the substratum and the humectation, thus causing the forming of local facies.
This formation is frequent in the western Mediterranean in areas with pure water and rough waters. It constitutes a major and particularly attractive element in the rocky coast landscape. It is found in the area where the waves break; its upper surface may emerge at 20-30 centimeters above the middle level of the sea. It develops on every type of substratum and can be up to 1 to 2 meters wide. The rim is formed by successive, more or less indurate and re-crystallised, layers of alga, with which the calcareous tests of some animals are mixed. The lower side presents many cavities that have been enlarged by rock-destroying organisms and in which a rich sciaphilous fauna finds refuge.

Bibliographie

European Topic Centre on Biological Diversity 2022. EUNIS marine habitat classification 2022 including crosswalks. Table Excel. (Source)