A coastal dune is a ridge of sand piled up by wind on the coast. Coastal dunes are common in countries where the coasts have vegetation like spinifex and marram grass and are exposed to strong winds from the oceans. The dunes form as a result of the vegetation trapping and stabilizing the sand. On some coasts, the dunes extend several kilometers inland and to heights of more than 100 meters. Coastal dunes, which act as barriers along the coast, protect human property like houses and roads against coastal erosion and flooding from waves. The dunes also provide a habitat for many animals including migratory birds. On some coasts, human activities have disturbed the coastal dunes. Moving vehicles and people walking across the dunes have damaged the vegetation on the coast. The loss of vegetation causes the sand to be easily blown inland, which can cover nearby roads, farms and buildings. In the southwestern coast of France, dunes that have moved inland have caused entire towns to be abandoned. Dunes can be stabilized by growing trees, shrubs and grass whose roots trap and anchor soil which prevents the sand from being blown inland. However, it is only an effective short-term measure. Vegetation growth cannot totally prevent erosion if human activities like property and resort development continue to take place along coastal areas. Difficulty is faced in seeking cooperation from those with investments in coastal areas. An example is the coastal dunes in Omaha Beach, New Zealand, which are stabilized by marram grass.
In some countries, people have planted mangroves to help protect the coast against erosion by strong waves and winds. Many of the mangrove trees have prop roots or kneed roots that anchor the trees firmly in the muddy soil. These roots also bind the loose soil, and protect it from erosion. However, young mangroves are fragile and require cooperation and commitment of local communities. Not all coastal areas are suitable for growing mangroves especially...
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