Wadden Sea Ecosystem 27: Exploring Contrasting Trends of Migratory Waterbirds in the Wadden Sea

Systematic counts of waterbirds have been conducted since the 1960s in the various countries of the international Wadden Sea. In the 2000s a lot of progress has been made with regard to data storage and data analysis, allowing a meaningful analysis and comparison of trends in the various regions of the Wadden Sea. Apart from many trends being negative, some of the trends show remarkable differences between countries. For instance, bar-tailed godwit increases in the Netherlands, shows a stable development in Lower Saxony, but decreases in Schleswig-Holstein and Denmark. Similarly, dunlin increases in the Netherlands, shows a stable development in Lower Saxony and Denmark, but decreases in Schleswig-Holstein. In contrast, oystercatcher declines nearly everywhere, except for Denmark, where it increases. Both from a conservation and management perspective, and from a scientific perspective, it is important to understand the cause, or causes, of these different trends. The 2009 report identifies a more or less complete set of hypotheses and name explanatory variables for these hypotheses.

Citation: Ens, B. J., Blew, J., Roomen van, M.W.J., Turnhout van, C.A.M. (2009) Exploring contrasting trends of migratory waterbirds in the Wadden Sea. Wadden Sea Ecosystem No. 27. Common Wadden Sea Secretariat, Trilateral Monitoring and Assessment Group, Joint Monitoring Group of Migratory Birds in the Wadden Sea, Wilhelmshaven, Germany.