Mangroves are a bunch of different trees that all grow in the same estuarine habitat throughout the tropics and subtropics. Generally mangroves are considered scruffy sort of forests occupying valuable coastal real estate, so it comes as no surprise that some 30-50% have been destroyed. It's no wonder why people think this way; they're muddy inhospitable places (for people) what with the stilt roots and all. This is particularly unfortunate because one of the primary reasons for destroying mangroves is for aquaculture, particularly shrimp, but mangroves are the place where many species reproduce and where the productivity of coastal fisheries is derived from. This is truly a case of robbing peter to pay paul; terrifically short sighted. Mangroves also play an important role of protecting coast lines against storms and even tsunamis. Now a study of mangroves shows that they are one of the most carbon rich of tropical forests probably because the saturated soils result in slow decomposition. So destroying mangroves puts more carbon back into the atmosphere than other forests, and mangroves take more carbon out of the atmospshere than other forests. So when you add that to the rest of the equation, conservation and restoration efforts (along with educational programs) makes great sense.