Combe Martin Coast line to IlfracombeThe coastline between Ilfracombe and Combe Martin is backed by lofty cliffs and etched with many sheltered covers and bays. From Ilfracombe, the coastline stretches for over 6 km to Combe Martin, a smaller town in a setting of sea, cliff and valley. There is a striking contrast between the irregularity of rocky shores, sandy stretches and all the intergrading types of shore along this coastline, presenting a rich variety of environments for a varied assembly of flora and fauna. Large Tidal Range Owing to the large tidal range along the Bristol Channel, the intertidal is often extensive and, because of its northern aspect, only moderately exposed. Different types of shore found along the coastline between Ilfracombe and Combe Martin includes Wild Pear Beach which is predominantly of firm sand with a few fissured reefs. It is moderately exposed and extends for over 150 metres. Sandy Bay is a moderately sloping, narrow sandy cove with irregular rock outcrops of Devonian slate and has an intertidal extent of about 250 metres. The shore at the Outfalls, near Ilfracombe, consists of a cobble and sand uppershore with reef ridges extending down the shore towards large mobile boulders on bedrock on the lower shore. Lester Point contrasts sharply with these shores. Here, the steep shore has an intertidal extent of only 5 or 6m and is more exposed to wave action. The steep bedrock is deeply fissured with an extensive covering of the barnacle Chthalamus montagui. Exposure Variations The degree of exposure is one of the many factors determining the distribution and occurrence of the varied marine life found in this section of coastline. Both composition and configuration of rock influences populations. The fissures and crevices found between the ridges of weathered shales harbours rich marine populations. The character of the rock surface, the direction and amount of slope is also influential. In areas such as Wild Pear Beach, the force of the waves over long periods has resulted in a gently sloping, relatively flat shore. The bedrock is largely broken in other areas, such as Hele Bay, Town Beach at Ilfracombe and The Outfalls, with pinnacles and gullies, overhangs and rockpools. There are a number of reefs along this coastline towards low water lying adjacent to sand which are largely sand scoured. Localised shelter gained from rockpools, crevices, gullies and overhangs increase the diversity of marine life on the shore. Rock Pools
Lower Shores Vertical and overhanging rock surfaces on the lower shores, as at Smallmouth Bay and Tunnels beach, support interesting and diverse faunal communities. Encrusting sponges Hymeniacidon perleve and Dysidea fragile and the erect bryozoans Scrupocellaria sp., Schizomavella linearis, Crisiidae sp., and Bugula plumosa are especially conspicuous. This site supports the rare Scarlet-and-gold-star Coral Balanophyllia regia and Isozonthus sulcatus. In addition, the Devonshire Cup Coral Caryophyllia smithii, the globular sponge Tethya auriantium and Polymastia mammilaris are present. These are species not commonly found in the intertidal, preferring shallow waters. At Hele Bay, good crevice communities are to be found in the fissures and crevices in the extensive bedrock on the shore. The green algae Chaetomorpha sp., Cladophora sp., and feather-like Bryopsis sp., are to be found in crevices at this site along with the red algae Lomentaria articulata, Catenella caespitosa and Plumaria elegans. Sponges are represented here by the encrusting form Hymeniacidon perleve and the bread-crumb spone Halichondria panicea. Anemones include the Beadlet Anemone Actinia equina, the Snakelocks Anemone Anemonia viridis and the Daisy Anemone Cereus pedunculatus. At the Town Beach, Ilfracombe, the crevices and fissures are dominated by the Mussel Mytilus edulis. The red algae Alnfeltia plicata, Gelidium latifolium, Polysiphonia sp. and Catenella caespitosa are also represented. Sandy shores provide startling contrast to exposed rocky shores. Although they appear barren and without a trace of life, after they have been uncovered by the tide for a while, broken surfaces and worm casts indicate the presence of life below the surface. As a habitat, sandy shores differ greatly from rocky shores. As there are no surfaces for attachment or sheltering rocks, protection is gained by a capacity to burrow. The species found in sandy pockets reflect this. In Sandy Bay, two worms commonly found on the lower shore are the Sand Mason Lanice conchilega and the Lugworm Arenicola marina. When the tide is out, the tubes of sand grains fringed with branching threads can be seen projecting about 3 cm from the surface of the sand. The lug worm Arenicola marina is responsible for the conspicuous shallow depressions and worm casts on the lower shore. Also found at Sandy Bay is Tellina tenuis. The bivalve can be recognised by its delicate, translucent oval shell, which is often tinted with pink, yellow or orange. A ramble along this coastline will be rewarded with stunning scenery, and if time is taken to pause, the beautiful colours and textures of the red, green and brown seaweeds will be revealed along with the often inconspicuous, but undeniably present, animal-life lurking in crevices, overhangs and rockpools. |
|||||
|