Development and history
The movement of glaciers in the Ice Age, changes in sea level and the actions of currents, waves, wind and people have played key roles in the development of our coasts. The ways that rock resists erosion has helped shape shorelines, creating headlands and bays. Equally, the type of sediment and ocean currents determine where sand or shingle beaches form. The coast’s exposure to the elements is also important. Mud and silt washed down by rivers can build up in sheltered areas, forming sweeping mudflats and saltmarshes. These are home to thousands of birds, fish and other wildlife.
Coasts are either eroding or growing through the transfer of sediment, a natural material that is formed by erosion and transported by wind, water or ice.
The erosion of the land by the sea can result in the creation of cliffs. Cliffs formed of hard rock can be steep and are battered by spray. This influences the kind of plants that grow there. Rocky shores are made up of rocks, boulders and pools within and just above the tideline and are often found at the foot of cliffs.
Softer rock is more likely to form ‘slumped’ cliffs, which are shallower and support different habitats. The continuing erosion of cliffs allows sediment to build up on soft shores as cliffs are broken down to form sandy beaches.
The coastline is forever changing; it is a dynamic environment shaped by changes in sea levels or by sudden storms.
An island nation
In the UK, no-one lives more than 80 miles from the sea. This closeness to the coast has held great cultural significance across the centuries. The sea is still important for peoples’ livelihoods. Many seaside towns now thrive on tourism and recreation. The coast is easily accessible for huge numbers of people, but recreational pressure can take its toll. Large numbers of walkers can damage sand dunes, saltmarsh and shingle beaches. Disturbance is also an issue for breeding birds and seals. This is particularly the case where habitats have been broken up or constrained, hemmed in by development, agriculture or sea defences.
Turning back the tides
Although the coastline is a naturally shifting boundary between the land and the sea, in many places humans have tried to limit or stop such change. Sea defences stretch around much of the coast (45% in England) in order to prevent the flooding of farmland, towns and villages. This is something of particular concern with the rapid rise in sea-levels due to climate change.
But these barriers do have a negative impact on our wildlife-rich coast. Soft coastal habitats are “squeezed” as the sea erodes them, but sea defences stop them from moving further inland as they naturally would. With less sediment being moved around, many soft shorelines are being eaten away rather than building up naturally.
However, habitats like saltmarsh can act as natural sea defences, protecting homes and businesses near the shore by absorbing the energy of the waves.
In some places, managed realignment is being used; sea defences are deliberately breached to allow coastal habitats to form further inland. The economics of this are sound, with the loss of farmland and other habitats offset by the costs saved in maintaining flood defences.
How you can help
Take care not to disturb wildlife and habitats when visiting the coastline, especially during the breeding seasons for animals like birds and seals. During the summer, many waders and seabirds nest on sand and shingle beaches, and seal pups are born during late autumn and winter. Disturbance at this time can lead to young being injured or abandoned.
The Wildlife Trusts believe that we cannot afford any further reduction in the quality or quantity of our coastal habitats. Allowing these habitats the space to adjust by relaxing artificially fixed sea defence lines will be essential. We are working within the framework of the UK Biodiversity Action Plan towards conservation of all coastal habitats and the wildlife they support. We are raising awareness that managed realignment and habitat restoration is an economically viable, environmentally acceptable solution.
Depending on where you live, local Wildlife Trust volunteers help with everything from recording marine wildlife sightings to beach cleans and educational work. Contact the Wildlife Trust for your area to find out more.