Worldwide, many wader populations have been shown to be in decline, though for some information is still lacking. Not all populations are declining, but long-distance migrants (a majority) appear to be at particular risk. Also at risk are sedentary species with small populations, which comprise a majority of the extinct and globally threatened species. The latter are better studied, and threats to their future are relatively well understood.
Large-scale population changes in Arctic and north-temperate regions are generally better documented than in the tropics or the Southern Hemisphere The reasons for declines in large and widespread populations are not well understood and explanations are mostly based on sparse and uncoordinated data.
The International Waterbird Census (I WC), coordinated by Wetlands International, provides a framework for monitoring non-breeding populations at a global scale. However, wader counts are not yet available from most countries for enough years to allow meaningful population trend analyses. Nevertheless there is considerable potential for trend analyses using IWC data in the future. Many other studies use different and uncoordinated methods. We still lack facilities for broad-scale analyses which would allow the reasons for observed changes in wader populations to be explored. A GIS referenced, decentralised, web-based database interface is proposed which would help explain these changes by linking wader m onitoring initiatives, and by providing integration with other environmental monitoring schemes.

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