Called "forests of the sea," mangroves refer to the dense plants growing in saline coastal habitats and river estuaries of the tropics and subtropics in Asia, Africa, South America and other areas. Mangrove forests are constantly and rapidly decreasing through large-scale deforestation carried out, for example, to clear space for shrimp aquaculture ponds, provide timber for factory and road construction, and make charcoal materials. From 1980 to 2005, it is said that approximately one-fifth of global mangrove forests had disappeared.