However, both have their disadvantages. Young mangroves require protection from animals, storms and human activities which could severely damage them. Dunes grasses mostly avert this issue by overlying them with matting. The matting protects the grasses form animals and human trampling. However, after the dune grass has matured and the matting has rotted away, signs and fences still need to be put up to protect the grass from humans, incurring more costs. .
Another method of stabilizing coasts is by encouraging coral reef growth. By encouraging coral reef growth, erosion can be reduced as wave energy is absorbed by the corals, reducing backwash. Coral reefs can also serve as breeding grounds and nurseries for fish, as well as form the basis of tourism and fishing industries. To promote coral reef growth, artificial reefs can be created and placed on the seafloor. They are usually made of concrete or steel and are colonised by corals, allowing them to function like normal reefs. In the Maldives, a coral-growing programme has been implemented to curb sever beach erosion since 1996. A cone-shaped structure of welded steel rods was placed off the coast of the island of Ihuru. Low-voltage, solar-generated electricity passed through the structure, stimulating corals to grow three to five times faster than normal. The island now sustains a large variety of corals, marine animals and organisms. However, cultivating coral growth is notoriously difficult. Only certain sites have the necessary conditions for coral growth and the corals themselves are very vulnerable to siltation. In addition, coral growth can take a few decades before any obvious results are shown.
Building seawalls is a method of coastal protection. Seawalls are protective structures mad of stone or concrete, built parallel to coasts. They reduce erosion of the coastal area by absorbing wave energy and reflecting incoming waves. They are often reinforced with boulders, steel and gabions.
