Posted 8th Jan 2018
The shoreline or beach is the point at which the land will meet the sea, consisting of rocks, sand, gravel, shingles, pebbles or cobblestones - in many cases, it will be a mixture of these
There consistency will typically be either sandy, muddy and / or stony, and again, can often prove to be a mixture of these.
The highest point of the tide reaches the strandline - here the tide will leave behind sediments such as seaweed, dead plants and animals, and, unfortunately, litter. The heights of the tides mean there will be often be several strandlines that can occur on a beach.
Strandlines provide the main input of energy to sandy shores and intertidal habitats. Particularly important on exposed shores, they act as precursors to sand dunes. As seaweed breaks down it produces organic matter which provides nutrients for pioneering plants looking to establish themselves on exposed beach and sand dune areas. Without this initial impetus, sand dune formation would be severely limited.
Where are they found?
The coastline of the UK boasts over 6,000 km of shoreline, with habitats that range from hard-and-soft-rock cliffs, sheltered coves, open beaches, river mouths, tidal inlets, estuaries, spits and barriers.
Why are they important?
Due to the tide, the bottom of the beach will often be covered by water, whereas the top of the beach will only be covered by water when the tide is high. The species of plant and animal vary greatly from the bottom to the top of the beach.
Our beaches and shorelines provide the UK with protection from the sea, dampening the waves and removing energy from storm surges. Despite this not always being the case, areas such as those in the North East will be subject to high levels of coastal erosion, with soft sediments being reclaimed by the sea.
The greatest biodiversity on the shoreline is in the strandline - this is usually made up of organic matter, particularly seaweeds, driftwood and other debris. Each high tide will see new life and material deposited which contributes to creating and supporting these unique habitats. Many species will depend upon them for food and shelter.
The richest communities are found in the thickest, wettest, rotting materials. These offer a rich food source for a wide variety of both marine and terrestrial invertebrates, including sandhoppers, beetles, small crabs and seaslaters. Large pieces of driftwood provide shelter on the shore for active predators that emerge at night, while there are many beetles who feed only on sea soaked wood. Many flies, such as the kelp fly, will lay their eggs in the strandline, while the emergent maggots will become food for predatory beetles and birds.
A broad group of birds will also feed along the shoreline including dunlins, oystercatchers, ringed plover, sanderlings and turnstones. Some of these are resident while others are migratory. These birds will search for sandhoppers, other invertebrates and kelp fly eggs which are laid on the seaweed.
Along with invertebrates and birds, strandlines also support other animals, including bats, shrews and voles. Even larger mammals - such as deer - will occasionally visit the strandline to support their diet by feeding on seaweed.
Are they threatened?
The main threat to the British shoreline is pollution from litter and rubbish which washes up on the tide. There are two methods to clean a beach - mechanical or hand beach cleaning. The heavy mechanical beach cleaners cause compaction of the sand - this form of cleaning removes the top 10-15cm of beach which will typically contain high numbers of invertebrates and significant quantities of organic matter – it’s been proven to cause a 90 per cent reduction in strandline species.
Hand cleaning allows the natural strandline to remain and support the beach ecosystem, while also getting people involved in beach conservation.
Sea walls and other such defences are being built to reduce the risk of flooding in human populated areas, as sea levels rise. However, this also serves to reduce the available shoreline habitats.
You can find out about what you can do to help here.
Text and information courtesy of The Wildlife Trusts