Mangroves for coastal defence. Guidelines for coastal managers & policy makers
The role of mangroves in protecting our coasts against natural hazards such as storms, tsunamis and coastal erosion has been widely acknowledged. Even so, the level of protection provided by mangroves remains subject to debate. Can mangroves reduce waves and storm surges? How will they influence the forces of a tsunami? Do they actually contribute to stabilizing coasts and build-up of soils? Can they keep up with sea level rise? The Nature Conservancy and Wetlands International together with the University of Cambridge set out to map the current state of knowledge about the role of mangroves in coastal defence and put the different findings and views in perspective. An extensive review process yielded three technical reports that describe the extent to which mangroves reduce wind and swell waves, storm surges and erosion and how they build up soils in response to rising sea levels. The conclusion is that mangroves can indeed reduce risk from a large number of hazards. This practical guidebook summarizes the findings of the reviews and provides practical management recommendations to coastal zone managers and policymakers. It helps the reader to assess the risk context in a target area, to define hazard-specific mangrove management interventions and to incorporate these in risk reduction strategies, climate change adaptation protocols and broader coastal development planning. Case studies provide practical examples of mangrove management approaches and references to background information, practical tools for risk assessment and mangrove management are provided throughout the book.