One of the most diverse ecosystems throughout the tropics. They are also one of the most endangered. Mangroves grow at the edge of the sea and provide a unique habitat for some 2,000 species of fish, invertebrates and plants. They are a valuable source of timber, pulpwood, fuel and charcoal, and of raw materials used in dyes, glues, rayon and tannin. They are also the breeding ground for a variety of fish, shrimps, crabs and molluscs. Mangrove forests play an important part in the desalination of sea-water. Because the roots of the trees are in the sea-water they protect shorelines from erosion and act as a bulwalk against storms.