Earth Observation for wetland inventory, assessment and monitoring

1. Wetland inventory, assessment and monitoring are widely recognized as essential tools for a range of purposes that underpin sound decision-making and the management of wetlands so as to maintain their ecological character, including the critical services they provide to people worldwide. 2. In recognition of this, the Ramsar Convention on Wetlands has adopted a suite of tools designed for: (i) describing the ecological character of wetlands; (ii) assessing the pressures and associated risks of adverse change; and (iii) monitoring the extent of any change that occurs as a consequence of management actions. 3. As a prelude to considering the application of Earth Observation techniques to wetlands a review of the needs and purposes of inventory, assessment and monitoring is provided and linked with the wetlands 'toolkit' that the Convention has developed. In particular the usefulness of Earth Observation for undertaking such work more widely, and making its results more accessible to users, is considered. 4. As the wide typological, geographical and temporal variability of wetlands poses major challenges for inventory and assessment there have been many calls for the effective application of Earth Observation. In response a number of remote-sensing techniques have been developed or are being considered, such as the application of satellite-based radar, with more recent attention given to the application of long-wavelength (L-band) synthetic aperture radar. Copyright (c) 2007 John Wiley & Sons, Ltd.