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  4. MA1-274 - Rhodochorton purpureum (anciennement Audouinella purpurea) et Cladophora rupestris sur parois des grottes de la partie supérieure et moyenne du rivage
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MA1-274 - Rhodochorton purpureum (anciennement Audouinella purpurea) et Cladophora rupestris sur parois des grottes de la partie supérieure et moyenne du rivage

Audouinella purpurea and Cladophora rupestris on upper to mid-shore cave walls
MA1-273 - Encroûtements de Rhodochorton purpureum (anciennement Audouinella purpurea) et de Pleurocladia lacustris (anciennement Pilinia maritima) sur parois et plafond des grottes de la partie supérieure et moyenne du rivage
MA1-275 - Wahlenbergiana mucosa (anciennement Verrucaria mucosa) et/ou Hildenbrandia rubra des parois des grottes de la partie supérieure et moyenne du rivage

Classification des habitats EUNIS 2022

Descriptif de l'habitat

Vertical and steeply-sloping upper walls at the entrances and inner reaches of upper to mid-shore caves that are partially sheltered from direct wave action characterised by a turf of the 'velvety' red seaweed Audouinella purpurea. Patches of green filamentous seaweed Cladophora rupestris can be present. The fauna is generally limited to limpets Patella spp., the winkle Littorina saxatilis and the barnacle Semibalanus balanoides, while they usually occur in low abundance. Filamentous or crust forming brown seaweeds may occur mixed with A. purpurea, often becoming a zone in its own right (unit MA1-273) above this unit. Other shade-tolerant red seaweed such as Catenella caespitosa and Lomentaria articulata may occur (but at lower abundance), and where freshwater seepage occurs, Enteromorpha intestinalis can form patches. Some variation in the species composition of the individual caves must be expected depending on local conditions. A. purpurea can be the only seaweed present in caves on the Thanet coast in south-east England. This biotope is known to occur in hard rock caves in north-east England and chalk caves in south-east England. Received after deadline: A. purpurea has changed name to Rhodochorton purpurea.
Situation: In hard rock caves, this biotope is generally found on the upper walls above units MA1-279 and MA1-278 and beneath the biotopes dominated by green and/or brown crusts (MA1-272; MA1-273). In chalk caves, this unit may cover the lower and upper walls, while it is usually found below units MA1-272 and/or MA1-273.

Bibliography

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