Despite restoration efforts by some countries, mangroves are being lost at a rate three to four times higher than land-based forests, with one fifth of all of the world's mangroves thought to have been lost in the past three decades, according to a new United Nations report. Mangrove losses have slowed to 0.7% annually, but the authors of the new atlas � the first global assessment of mangroves in more than a decade � warn that any further destruction due to shrimp farming and coastal development will result in significant economic and ecological declines. Mangroves � forests straddling land and sea � are believed to generate up to $9,000 per hectare, a strong argument in favour of mangrove management, protection and restoration. The global area of mangroves, some 150,000 square kilometres, is equivalent to the area of Suriname or half of the Philippines. "Together, the science and the economics can drive policy shifts," said Achim Steiner, Executive Director of the UN Environment Programme (UNEP). He noted that 1,200 protected areas are safeguarding one quarter of the world's remaining mangroves while many countries are embarking on major restorations, "a positive signal upon which to build and to accelerate a definitive response in 2010, the UN's International Year of Biodiversity". More than 100 top mangrove researchers and organisations provided data, reviews and other input for the World Mangrove Atlas, a joint effort of UNEP, the UN Food and Agriculture Organization (FAO), and other groups. "Mangrove forests are the ultimate illustration of why humans need nature," said Mark Spalding, lead author of the publication, which he noted illustrates the "extraordinary synergies" between people and forests.