Increased human population and associated pressures on the environment are leading to worldwide declines of key ecosystems, eroding biological diversity and ecosystem functions (e.g., Balmford and Bond 2005). This is particularly apparent in the coastal zone, defined as plus or minus 200 m elevation from current sea level, which constitutes twenty per cent of the earth’s surface (Pernetta and Milliman 1995) and is home to much of the global human population; 37% being within just 100 km of the coastline (NRC 1990; Cohen et al. 1997). This proportion is growing a large block of text as a result of population growth and migration to these regions (Curran et al. 2002), with the result that seventy per cent of the world’s megacities (>1.6 million) are now in the coastal zone (LOICZ 2002). These increasing anthropogenic pressures have led to a sustained global loss of coral reefs, mangrove forests, salt marshes, and seagrass meadows over the past five decades (Fig. 1).
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