Rockpooling Destination: Revisit South- West Penwith, October 2014 - Lichen Communities of the shore

The rocky shore is a high energy environment comprised of boulders and bedrock with rock pools, crevices and gullies.

The rocky shore is comprised of boulders and bedrock with rockpools, crevices and gullies. Habitat classification: LR.HLR (High energy littoral rock) EUNIS: A1.1 , LR.FLR.Rkp (Rockpools) EUNIS:A1.41 and LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock) EUNIS: B3.11.

The high energy environment of the shore leads to an extended lichen zone, that descends over much of the boulder field, which apart from Littorinids is relatively barren. Patches of lichens extend further down into the barnacle communities, which dominate from the upper to lower shore, inter dispersed by shallow coralline rockpools in the mid shore, and deeper cobble filled rockpools on the lower shore. As the low tide mark is reached wave tolerant seaweeds lace the gullies.

Winter waves had washed many 'by the wind sailors' (Velella velella) onto the shore. These extraordinary creatures are not one, but many organisms that form a colonial hydroid that floats on the oceans, driven by the wind against its sail. During winter storms hundreds can be washed up onto the shores of the Lands' End peninsular.  

'By the wind sailors' (Velella velella) are often washed up on the Cornish shores over Winter.

V. velella use their dorsal projections as a sail to sail across the oceans in search of small pelagic prey, which they catch with their stinging tentacles.

Habitat classification of the shore:

Substrate	LR (Littoral rock)
Habitat	LR.HLR (High energy littoral rock)		LR.FLR (Features of littoral rock)
Biotope complex	LR.HLR. MusB (Mussel and/or barnacle communities)	LR.HLR.FR (Robust fucoid and/or red seaweed communities)	LR.FLR.Lic.(Lichens on    supralittoral and littoral fringe rock).		LR.FLR.Rkp (Rockpools)
Biotope			LR.FLR.Lic.Ver (Verrucaria Maura on  littoral fringe rock)	LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock)	LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)
SubBiotope			LR.FLR.Liv.VerB (Verrucaria maura and sparse barnacles on exposed littoral fringe rock)		LR.FLR.Rkp.Cor.Bif (Bifurcaria bifurcata in shallow eulittoral rockpools)

Habitat classification of the shore anticlockwise from the top of the shore down:
 LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock)
 LR.FLR.Liv.VerB (Verrucaria maura and sparse barnacles on exposed littoral fringe rock)
LR.FLR.Lic.Ver (Verrucaria Maura on  littoral fringe rock)
  LR.HLR. MusB (Mussel and/or barnacle communities)
 LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)
A crevice within the habitat LR.HLR. MusB (Mussel and/or barnacle communities)
 LR.FLR.Rkp.Cor.Bif (Bifurcaria bifurcata in shallow eulittoral rockpools)
and LR.HLR.FR (Robust fucoid and/or red seaweed communities).

Below are images of the organisms you may encounter in the lichen communities of the shore:

Lichens cover boulders of the supralittoral and littoral fringe. Yellow and grey lichens cover the boulders of the supralittoral  and below the black Tar lichen covers the boulders of the littoral fringe. LR.Flr.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3.111 and LR.FLR.Lic.Ver (Verrucaria Maura on  littoral fringe rock) EUNIS: B3.113.

 Yellow and grey lichens cover the boulders of the supralittoral. Habitat classification: LR.Flr.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3.111.

Tar lichen (Verrucaria Maura) covers the boulders of the littoral fringe. Habitat classification: LR.FLR.Lic.Ver (Verrucaria Maura on  littoral fringe rock) EUNIS: B3.113.

Periwinkles are the most prolific mobile fauna of the boulder field, where they seek refuge within crevices. Rough periwinkles (Littorina compressa nigrolineata) and occasional barnacles. Habitat classification: A variant of LR.FLR.Liv.VerB (Verrucaria maura and sparse barnacles on exposed littoral fringe rock) EUNIS: B3.1131.

Rough periwinkles (Littorina sp) and sparse barnacles.

Sparse barnacles, Small periwinkles (Melarhaphe neritoides) and Rough periwinkles (Littorina compressa nigrolineata) aggregate within pits and a depression of the boulder faces. 

Littorina compressa nigrolineata, sparse barnacles and limpet (Patella vulgata).

Littorina compressa nigrolineata

Littorina compressa nigrolineata