Degradation of Wadden Sea causing decline in wader numbers

The Wadden Sea is an expansive network of rich habitats in the North Sea, but its richness is also heavily exploited by humans. photo: Ralf Roletschek (commons.wikimedia.org).
The Wadden Sea is an expansive network of rich habitats in the North Sea, but its richness is also heavily exploited by humans. photo: Ralf Roletschek (commons.wikimedia.org).
The first-ever migration report of whole East Atlantic Flyway has shown that the Wadden Sea, a huge migration stop-over zone in the North Sea, is in danger.

Europe's Wadden Sea is a vast coastal wetland comprising tidal flats, islands, salt marshes and other habitats. It stretches more than 280 miles along the North Sea coast of The Netherlands, Germany and Denmark, and at more than 6,000 square miles, it is one of the largest wetlands in the world.

This Natura 2000 (EU nature protection network) site is used by 12 million birds every year, and is crucial for more than 60 species at the breeding, migration and wintering stages of their lives. It is also one of the most important and extensive sites on the East Atlantic Flyway, the path used by about six million birds to migrate between their breeding grounds in the Arctic and their wintering sites in Western Europe and West Africa, thousands of miles away. The birds need the Wadden Sea and other similar sites to be able to rest and feed, before continuing their journeys. Degradation or even disappearance of these sites is, therefore, a threat to migratory birds, and makes assessing the populations of these species a good indication of the health of the habitats.

Alarmingly, a report has revealed that of the 66 species using the East Atlantic Flyway, waterbirds that feed on shellfish, crabs and worms in the Wadden Sea have decreased in number by 2.5 million between 2003 and 2014, although the fish-eating species have seen a rise. More disturbingly, birds that are largely dependent on the Wadden Sea, like Oystercatcher, are declining in comparison with those that are not. Populations that breed in the Wadden Sea also seem to be in decline.

These findings have been published in a census report on migratory birds along the East Atlantic Flyway conducted in 2014 by the Wadden Sea Fly-way Initiative, Wetlands International and BirdLife International, together with national organisations and government institutions from the countries directly concerned.

The report explains the findings of the annual International Waterbird Census, the long-term site-based monitoring scheme for non-breeding waterbirds. What has made the 2014 count different is that it focuses on the fly-way as a whole – the first time such simultaneous and integrated monitoring has been attempted. About 1,500 birders in 30 countries counted almost 15 million individual birds, and the findings were compared with individual surveys from 1980 onwards.

These counts how that overall flyway population trends are more positive than those in the Wadden Sea. This suggests that differences in the Wadden Sea are mainly caused by local factors such as predation and depleted food resources rather than global factors like climate change; the latter are most likely caused by land reclamation, an increase in fishery activities, oil and natural gas extraction, and pollution.

The count has proved that despite being declared a World Heritage Site by the United Nations in 2009 and being a Natura 2000 site, the Wadden Sea remains in danger. To improve the situation, the Programme toward a Rich Wadden Sea (PRW) – who part-funded the surveys – has introduced dynamic zones and 'Wadden Sea hosts', who provide information on the area and the rules of conduct to boaters visiting the region. The programme is also working on anti-predation and conservation measures, such as restoring natural structures that provide food and shelter to birds on the coast, and the creation of climate-proof islands (to withstand rising sea levels).