Beyond the uninhabited Wadden Island Rottumeroog, on the border between the Netherlands and Germany, lies the 100 km² Ems-Dollard estuary. The Dollard is actually a large embayment where the rivers Ems and Westerwoldse Aa flow into the Wadden Sea. It's these rivers which make the Dollard so unique. They supply fresh water which gradually mixes with the salty Wadden Sea, forming a brackish water region. There are few areas nowadays where fresh and salt water gradually join. This is also one of the exceptional features of this wetland.
Because the area is connected to the Wadden Sea, the Dollard is influenced by the tide. The difference between high and low tide can reach up to 3 meters! Just about the entire region floods during high tide. The Dollard is the last large-scale brackish water tidal landscape of Europe and is one of the most important nurseries of the North Sea. This is where innumerous numbers of birds come, seals are born and a variety of rare and unique plants grow.
One of the characteristics of the Ems-Dollard region are the salt marshes. As far as you can see in the vast outskirts lie pieces of flats overgrown with plants. The salt marshes formed as the mud flats flooded during high tide, leaving a little bit of mud behind each time. Eventually, the flats were so high that plants were able to take root in the ground. Because the Ems-Dollard is brackish, you find unique and rare plants in this region that have adapted to the prevailing circumstances. Examples are salicornia species, sea aster and common brass buttons. Furthermore, the mud flats are made up of pure sea clay and not a sandy bottom with a layer of mud, as found in the other areas.
Home for innumerous animals
Animals also make good use of the marshes. The Dollard is a bird region of global significance. The elevated regions form a paradise for them. The number of geese, ducks, gulls and waders present run into hundreds of thousands during the migration period! Tidal flat birds use the salt marshes during high tide to rest. This is where they wait till the water has disappeared from the mud flats where they forage for food. A number of (tidal flat) birds also use the salt marshes for breeding, such as the redshank, the arctic and common tern, the avocet and the black-headed gull. Even underwater, the Ems-Dollard is rich in animals. The number of fish species is also very high. The adjacent flats are a nursery for seals. The Dollard itself is an important haul out for more than 100 of these marine mammals!