Prasiola stipitata on nitrate-enriched supralittoral or littoral fringe rock

Description (English)

Exposed to moderately exposed bedrock and large boulders in the supralittoral and littoral fringe that receives nitrate enrichment from nearby roosting sea birds and is characterised by a band or patches of the ephemeral tufty green seaweed Prasiola stipitata or Prasiola spp. This typically grows over the black lichen Verrucaria maura in the littoral fringe or yellow and grey lichens in the supralittoral zone. In damp pits and crevices, species such as the winkle Littorina saxatilis, amphipods and halacarid mites are occasionally found. B3.112 often covers a smaller area than 5m x 5m and care should be taken to notice/record this biotope. The biotope can be associated with artificial substrata such as septic tanks, and in supralittoral areas influenced by sewage seeps or agricultural run-off.
Situation: This biotope is found at the top of rocky shores in the splash zone below colonies of nesting or roosting birds growing. B3.112 may also be found at the entrances to and on the ceilings of littoral caves or in patches on large boulders, where birds may be roosting. It can be found in the B3.111 or B3.1132 zones.
Temporal variation: P. stipitata reaches its maximum abundance during the winter months. It generally dies out during the summer in southern Britain, when the biotope reverts to either B3.111 or B3.1132. In the cooler northern areas it may be present all year round.

Source: EUNIS habitat classification