The spatial coverage of marine and coastal protected areas worldwide has shown a rapid increase in recent years. Over 32% of the world's coral reefs and over 36% of the world's mangrove forests now fall within protected areas. However, simple measures of extent are insufficient for assessing progress toward achieving global targets. Notably, the CBD Aichi Target 11 calls for 'at least 17 per cent of terrestrial and inland water areas, and 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services' to be protected. There is, therefore, an urgent need to assess how well protected areas cover these areas of importance for ecosystem services.