Abstract

This assessment is based on reviews of the extent of wetland inventory in seven regions of the world. A key conclusion is that little is still known about the extent and condition of the global wetland resource. It was not possible to make reliable overall estimates of the size of the wetland resource globally or regionally. Previous estimates range from 5.3 to 9.7 million km² but present analyses now suggest a tentative minimum of 12.8 km². Recommendations focus on the need for national inventory programmes and the inclusion of basic information on the location and extent of each wetland and its major ecological features as a forerunner to collecting further management-oriented information. Thus, the following core data should be collected: area and boundary, location, geomorphic setting, general description, soil characteristics, water regime, water quality, and biotic characteristics. Further, the development of standardized methods for data collection, collation and storage are called for. These should address the use of remotely sensed data and storage of information in electronic formats, including Geographic Information Systems and recording key information in a meta-database. Habitats of priority for future inventory are seagrasses, coral reefs, salt marshes and coastal flats, mangroves, arid-zone wetlands, peatlands, rivers and streams, and artificial wetlands.