Grazers’ key role

The area’s development started with the arrival of tens of thousands of greylag geese who, with their pointy beaks, started grazing the marshland. This stopped it becoming overgrown with reeds and created a mosaic of open water and specific marsh vegetation which provided habitats for many species of bird and plant.
In drier areas the wild cattle, deer and horses (large grazers) are responsible for stopping the area becoming overgrown with willows. In this way they too create more variety at the site.

Dynamic

The grazers and the weather conditions provide a natural dynamic. Nature continually develops and changes. Sometimes certain species can occur and flourish there, then there is a period during which they spread out or die off, thereby serving as food for others. Just like dead trees in woods, dead animals play an important role in the ecosystem. All manner of organisms from bacteria and carrion beetles to foxes, ravens and white-tailed eagles benefit from cadavers.

Key species

Species that have a major effect on an area are referred to as ‘key species’. These key species occur almost nowhere else in Europe; at least not in sufficient numbers to be effective. At the Oostvaardersplassen a system of key species has been able to develop. A complex food web has developed which enables all manner of species of plant and animal to survive.

Import

The greylag goose, an important grazer, reached the area itself. The other large grazers (Heck cattle, red deer and konik horses) could not reach the area themselves as there was no physical link with their original habitat. This is why they were released into the area. They have since developed into wild animals that live in herds and adopted their role in the ecosystem.