Monday, 29 February 2016

Characterising species of the supralittoral zone

The supralittoral zone marks the upper extent of the intertidal and in some cases is considered a terrestrial habitat i.e within the EUNIS classification it is placed with the coastal habitats.

The supralittoral or 'splash zone' is the area at the top of the shore that receives the salt spray from the waves, as such, those shores experiencing greater exposure and salt spray from waves have larger supralittoral zones. Rock angle, shade and local climate also influence the extent of the zone.

The supralittoral zone is characterised by rocks covered in lichens, salt tolerant angiosperm and pools with variable salinity and temperatures. The organisms are highly specialized to endure variable salinity, periods of exposure and occasional immersion during storms. 

Lichens are one of the characteristic species of the supralittoral and often come to dominate the available rock. Concordantly the presence of lichens is a key component in the habitat classification of supralittoral rock and is captured by the habitat description: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3.111.
One of the few mobile species to extend up into the supralittoral from the intertidal is the rough periwinkle (Littorina saxatilis).   

A variety of grey and yellow lichens can be found in the supralittoral.

The seaslater (Ligia oceanica) can also be observed.

Salt tolerant plants can also occur.

The distinction between the lichen and plant communities of the supralittoral and the terrestrial vegetation is often unclear. 

Rockpools within the supralittoral experience variable salinity and temperature making them inhospitable for many species. Habitat classification: EUNIS A1.42 (Communities of rockpools in supralittoral zone).

In this example tadpoles are found in the supralittoal rockpools of the shore.

Tuesday, 23 February 2016

An introduction to zonation on intertidal shores

Where the land meets the sea two worlds join, one or air and the other of sea water.

As the tide rises and falls this stretch of land, refereed to as the intertidal zone, alternates between being exposed to the air and covered by sea.

The relative environmental pressures of submergence and exposure change retrospectively throughout the intertidal zone in relation to altitude from the low water mark. Other factors such as predation and competition also act to influence the communities found. 

The combination of all these factors can often result in repeated and definable communities of species at certain altitudes and/or exposures across the intertidal zone.

Such distributions of communities in relation to altitude or, height on the rocky shore is often referred to as zonation. Zonantion is often discussed in terms of dominant seaweeds present and is best exemplified on sheltered rocky shores. 

Zonation is not always clear cut (see previous blog post: and is affected by factors for which altitude on the shore is often correlated. 

The following posts look at some of the characterising species of the general shore 'zones'; although these can be found else where, they are often characteristic of a particular zone of the shore.

Below are images of some of the different intertidal zones found on UK rocky shores.

The different zones of the intertidal rocky shore in relation to altitude.

The communities on this exposed rocky shore in Shetland exhibit distinct distributions in relation to rock altitude and exposure. Yellow and grey lichens occur at the highest elevation of the rock and mark the supralittoral zone. Below, the rocks of the littoral fringe appear black, from the tar lichen (Verrucaria maura) which is overgrown on the more sheltered vertical rock, by a fringe of the brown channel wrack (Pelvetia canaliculata); the rocks of the upper shore become increasingly grey due to the barnacle communities which are inter-dispersed by patches of the black, Lichina pygmaea.  Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3.111, LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock) EUNIS: B3.113 and LR.HLR.MusB.Cht (Chthamalus spp on exposed upper eulittoral rock) EUNIS: A1.112.

The communities on this sheltered rocky shore in Shetland exhibit distinct distributions in relation to rock altitude. Yellow and grey lichens occur at the highest elevation of the rock and mark the supralittoral zone. Below, the rocks appear black, from the tar lichen (Verrucaria maura) and the eulittoral is characterised by fucoids with a green patch of ephemeral greens marking fresh water run off entering the shore. Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3.111, LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock) EUNIS: B3.113, LR.LLR.F (Fucoids on sheltered marine shores) EUNIS: A1.31 and  LR.FLR.Eph (Ephemeral green seaweed communities - Fresh water influenced) EUNIS: A1.45.

Monday, 15 February 2016

Regional names of common shore species

The marine animals of the shore often have a common name in addition to their Latin name. These common names can vary around the UK. 

Below are some examples:

Generic common name: Common Whelk – Shetland common name: Buckie – Latin name: Buccinum undatum

Generic common name: Three spot cowrieShetland common name: Grotti Buckie – Latin name: Trivia monacha

Generic common name: Edible Periwinkle – Shetland common name: Black Whelk – Latin name: Littorina litorea

Generic common name: Goose barnacles – Shetland common name: Claiks – Latin name: Lepatidae

Generic common name: Razor Shell – Shetland common name: Spoot – Latin name: Ensis sp

Generic common name: Seaslater – Cornish common name: Grammercel – Latin name: Ligia oceanica

Because of the variance in common names recorders log the organisms of the shore by their Latin names which do not change regionally.

Washed up Silver Birch is referred to as gooniemans candle is Shetland