Rockpooling Destination: Revisit West Penwith, December, 2015

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

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, interdispersed 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.

Habitat classification:

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.HLR.MusB.Cht (Chthamalus sp on exposed upper eulittoral rock)	LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock)		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)

Below are images of the organisms you may encounter in these habitats:

A 'By the wind sailor' (Velella velella)  washed up high onto the shore. This is a pelagic hydrozoa that is often washed up onto shores during the winter months.

Lichens have a patchy distribution, covering the larger and more stable boulders and bedrock of the supralittoral and littoral fringe rock. Habitat classification: LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock) EUNIS: B3.11.

Many boulders are too mobile to facilitate lichen growth, in such circumstances lichen growth is restricted to areas surrounding 'protected' crevices.

The boulders of the littoral fringe support a community of  rough and small periwinkles with seasonal growths of green ephemeral seaweeds. Towards the lower extend of the littoral fringe rock, sparse barnacles are found. On the boulders where the V. maura is absent the littoral fringe is identified by the presence of other organisms, including rough (Littorina saxatilis) and small periwinkles (Melarhaphe neritoides) and sparse barnacles. The ineffective application of the JNCC and EUNIS habitat classification to the littoral fringe boulder habitat is rectified by the much broader 1993 phase 1 habitat classification which seems to capture these environments under the boulder habitat classification which is in turn is listed under the EUNIS website as comparable to the habitat classification supralittoral rock (lichen or splash zone).

On stable bedrock and larger boulders  V. maura is evident. Common limpets (Patella vulgata), sparse barnacles and an increased diversity of periwinkles (Littorina sp)are also present. The mobile organisms congregate within crevices, nooks and crannies or the leeward sides of rock in a bid to avoid wave exposure.

Littorinid identifications helped by Ian Smith..... 

Rough periwinkles (Littorina saxatilis agg)

Rough periwinkles (Littorina saxatilis agg)

Rough periwinkles (Littorina compressa)

Rough periwinkles (Littorina compressa)

Rough periwinkles (Littorina sp)

The bedrock of the upper eulittoral supports barnacle communities and shallow coralline rockpools. Patches of the lichen, Lichina pygmaea occur on certain rock faces, as does Verrucaria mucosa, whilst the crevices support mussels (Mytilus edulis), periwinkles and  beadlet anemones (Actina equina). Habitat classification: LR.HLR.MusB.Cht (Chthamalus sp on exposed upper eulittoral rock) EUNIS: A1.112 and LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock) EUNIS: A1.113.

Patches of Lichina pygmaea show seasonal die back.

Barnacles

Coralline rockpools occur throughout the bedrock of the eulittoral. During the winter months the ephemeral seaweeds of the pools have died back, as too has those corallinaceae crusts that were exposed to the sun. China limpets (Patella ulyssiponensis),  M. edulis and the seaweeds Corallinaceae crusts, Corallina officinalis, Chondrus crispus and ephemeral greens can be found within these pools. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.411.

Mid eulittoral bedrock and less stable boulders, support a more patchy distribution of barnacles, and appear 'pinker' as the granite colour can be seen. Robust fucoids cling on in this environment and between the boulders are filter feeders and robust red seaweeds and beadlet anemones (Actina equina) and among boulders in sheltered gullies are dog whelks (Nucella lapillus) and topshells. Habitat classification: LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock) EUNIS: A1.113.

A flat topshell (Littorina sp) found among the robust fucoids.

Where wave exposure and scour from pebbles and cobbles is high, faunal cover is low.

Bedrock of the lower eulittoral supports an ever increasing diversity of filter feeders, that form 'turfs' with the robust red seaweeds.Habitat classification: LR.HLR.FR (Robust fucoid and/or red seaweed communities) EUNIS: A1.12

Sponges occur beneath shaded over hangs.

Red seaweeds including, Palmaria palmata, Corallinaceae crusts and foliose reds, lace a gully of the lower eulittoral. 

Red seaweed diversity is highest on the lower eulittoral, comprising Calliblepharis sp, Fucus serratus,  Chondrus crispus, Mastrocarous stellatus, Corallinaceae crusts, Corallina officinalis,  Geldium sp and others.

The coralline rockpools of the lower eulittoral support higher densities and diversity of red seaweeds and anemones. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.411.

In those rockpools filled with coarser sediment the diversity is less.

Characterising species of the littoral fringe rock

           

The littoral fringe zone occurs between the supralittoral and eulittoral zones and in some cases is considered a terrestrial habitat i.e. within the EUNIS classification it is placed with the coastal habitats and the supralittoral and littoral fringe lichen communities come under the one broad habitat complex, Lichens or small green algae on supralittoral and littoral fringe rock B3.11. 

The littoral fringe receives the salt spray from the waves, as such, those shores experiencing greater exposure and salt spray from waves have larger littoral fringe zones. Rock altitude, angle, shade and local climate also influence the extent of the zone. These factors also effect the distinction between the supralittoral and littoral fringe communities so that sometimes they are distinct or are intermingled.

The littoral fringe zone is often characterised by rocks covered in the black tar lichen (Verrucaria maura), rough periwinkles, channel wrack, ephemeral seaweeds, sparse barnacles and pools with variable salinity and temperatures. 

Other organisms that come under the broad lichen habitat complex (LR.FLR.Lic) that are also characteristic of littoral fringe communities are green seaweeds such as Blidingia sp, Ulothrix sp and Urospora sp that can characterise areas of littoral fringe soft rock or vertical rock where there is fresh water run off. 

The organisms living in this zone are highly specialized to endure variable salinity and extended periods of air exposure.  

The littoral fringe can often be discernible from a distance by the presence of the black tar lichen (Verrucaria maura) that covers the rock, above which the rocks of the supralittoral appear light grey whilst below the rocks of the eulittoral appear beige.

High wave exposure leads to an extended splash zone enabling lichens to colonise further up the cliffs. In the photograph above two distinct bands of differing lichen communities can be seen. At the highest position on the supralittoral are yellow and grey lichens, whilst on the littoral fringe below V. maura covers the bedrock. Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3111 and LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock) EUNIS: B3.113.

Variations in rock altitude can lead to a mosaic like distribution of the supralittoral and littoral fringe lichen communities. Also at this altitude on the shore fluctuating temperatures and salinity lead to prolific growth of Ulva spp (formally Entomorpha spp) in some of the rockpools. Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3111, LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock) EUNIS: B3.113 and  LR.FLR.Rkp.G (Green seaweeds (Entomorpha spp. and Cladophora spp.) in shallow upper shore rock pools) EUNIS: A1.421. 

The lichen communities are not always present on unstable rock substrates, and this can make the distinction between the the supralittoral and littoral fringe difficult. On the shore above the supralittoral and littoral fringe rock is distinguishable by its 'white colour' as these boulders do not experience daily submergence. The yellow and grey lichens of the supralittoral are able to grow on the boulders of the most upper shore that have been thrown up during storms and are only rolled during the most extreme storms, however the remaining boulders of the supralittoral and littoral fringe are rolled just enough during periodic storms to prevent their growth.

On the shore above the boulders are larger and more stable allowing for a more established and diverse lichen community to develop. The black tar lichen (V. maura) is still absent from many of the boulders that would occupy the altitude of the littoral fringe but does occur on the bedrock of this height. On the boulders where the V. maura is absent the littoral fringe is identified by the presence of other organisms, including rough (Littorina saxatilis) and small periwinkles (Melarhaphe neritoides) and sparse barnacles. The ineffective application of the JNCC and EUNIS habitat classification to the littoral fringe boulder habitat is rectified by the much broader 1993 phase 1 habitat classification which seems to capture these environments under the boulder habitat classification which is in turn listed under the EUNIS website as comparable to the habitat classification supralittoral rock (lichen or splash zone).

On stable bedrock the black lichen, V. maura is one of the most characteristic species of the littoral fringe. Living among this lichen you may also encounter L. saxatilis, ephemeral seaweeds and sparse barnacles. Because of the extended period of exposure the organisms tend to aggregate in crevices or shaded areas in order to reduce desiccation. The rockpools of the littoral fringe are species poor. Fluctuating temperatures and salinity lead to prolific growth of Ulva spp (formally Entomorpha spp) in some of the rockpools whilst others support the occassional amphipod. Habitat classification: LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock) EUNIS: B3.113 and  LR.FLR.Rkp.G (Green seaweeds (Entomorpha spp. and Cladophora spp.) in shallow upper shore rock pools) EUNIS: A1.421. 

A characteristic species of the lower littoral fringe rock of some shores is channel wrack (Pelvetia canaliculata) and on moderately exposed shores an accompanying spare barnacle community. Habitat classification: LR.MLR.BF.PelB (Pelvetia canaliculata and barnacles on moderately exposed littoral fringe rock) EUNIS: A1.211.

P. canaliculata cover increases on sheltered shores and the there is no associated barnacle community. Habitat classification: LR.LLR.F.Pel (Pelvetia canaliculata on sheltered littoral fringe rock) EUNIS: A1.321.

Rockpooling Destination: Ardnamurchan Light House, Scotland, May 2015

The shore comprises bedrock with crevices, gullies, rockpools and varying amounts of sand. Yellow and grey lichens characterise the supralittoral, with tar lichen and channel wrack in the littoral fringe. The littoral communities below comprise barnacles, periwinkles, anemones and sand scour tolerant seaweeds.

Below are images of organisms you may encounter whilst rockpooling in these habitats:

The shore comprises bedrock and sand. The supralittoral rock of the shore supports yellow and grey lichens and sea pinks (Armeria maritima). Below, the black tar lichen, Verrucaria maura covers the rock. Habitat classification: LS.Lsa (Littoral sand) EUNIS A.2, 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.

Sea pinks and lichens have a patchy distribution among the pinnacles of rock.

Channel wrack (Pelvetia canaliculata) occurs as a band on the littoral fringe bedrock.

Rough periwinkles (Littorina spp) occur within the littoral fringe
 and upper shore.

A rough periwinkle (Littorina spp)

Ulva spp (formally entermorpha spp) occurs in many of the upper shore, sand filled rockpools.

Ulva spp 

Barnacles and limpets of the upper shore exhibit an aggregated distribution, positioning themselves in the leeward side of the bedrock.

This distribution is seen across the shore with barnacles and limpets aggregating in the leeward side of the bedrock.

Barnacles

Patches of  Lichina pygmaea can be found among the barnacle communities.

Lichina pygmaea and Edible periwinkle (Littorina littorea)

Littorina littorea

Littorina littorea

Littorina littorea

Snakelocks anemone (Anemonia viridis)

Mastrocarpus stellatus

Among the shells of the upper shore, terrestrial insects like wood lice can often be found.