Mangroves are highly productive, biodiversity-rich forest ecosystems adapted to survive in the harsh interface between land and sea. They provide resources such as timber, firewood, thatching materials and a wide range of other products, they serve as habitat for fisheries, and they help protect coastlines from tsunamis, storm surges and erosion. But they are under threat. An estimated 35 600 km² were lost between 1980 and 2005, and the annual rate of loss between 2000 and 2005 was 0.66%.