Description of [Audouinella purpurea] and [Pilinia maritima] crusts on upper and mid-shore cave walls and ceilings
Golden brown velvety growths of the brown algae Pilinia maritima occurring in mats with the red alga Audouinella purpurea forming on cave walls and upper littoral levels of cliffs. Fauna is sparse and limited to occasional individuals of the winkle Littorina saxatilis and spirorbid polychaetes. This assemblage is thought to be is widespread throughout Britain, although there are currently few records available. More information are needed to validate this description, which is based on information from the Thanet intertidal survey (Tittley & Spurrier 2001). Situation: This biotope is found at the entrances and the inner reaches of caves between a band of unit A1.444 and the A1.442 zone above. Temporal variation: Some variation in the species composition of the individual caves must be expected depending on local conditions.