Verrucaria maura on littoral fringe rock

Description (English)

Bedrock or stable boulders and cobbles in the littoral fringe which is covered by the black lichen Verrucaria maura. This lichen typically covers the entire rock surface giving a distinct black band in the upper littoral fringe. The winkle Littorina saxatilis is usually present. Two variants are defined which both occur in a wide range of wave exposures. On exposed shores V. maura may occur with sparse barnacles such as Chthamalus spp. or Semibalanus balanoides and may be covered by a band of ephemeral seaweeds such as Porphyra umbilicalis or Enteromorpha spp. (B3.1131). Above B3.1131 or on more sheltered shores is a species poor community consisting mainly of V. maura and L. saxatilis (B3.1132).
Situation: This biotope occurs below the yellow and grey lichen zone (B3.111) and above eulittoral communities of barnacles and fuciod algae.
Temporal variation: Distinct band of red or green ephemeral algae may obscure the black lichen band at certain times of the year.

Source: EUNIS habitat classification