Oostvaardersplassen - Natural Processes

Natural Processes

Given that the Oostvaardersplassen is below sea level, many of its primary processes have been regulated. As the wetlands have been so spectacular, a dyke was made around it to prevent the process of groundwater-related subsidence. While this had temporary advantages, it created a water body with no open connections to the rest of the polder and the negative effects are only now being understood.

The cattle, deer and horses have multiplied in the Oostvaardersplassen. However there is a limit to the number of animals the area can sustain. In the absence of natural predators the rangers shoot animals that are unlikely to survive. It is quite natural for 30% to 60% of the population to die in this way. After a die off, the vegetation has a chance to recover and this will get the first natural afforestation of the area under way.

The large herbivore die offs are also closely related to the confined nature of the reserve and the flat nature of the reclaimed land with very little shelter. It is fenced and thus the large herbivores are unable to migrate away from the over grazed areas in Winter to find either shelter or forage. All the large herbivores have an annual cycle of nutrition. Typically in winter and early spring their metabolism slows down. This is also the period in which they are designed to loose condition (body fat). This is where the ability to seek shelter as they would in a natural environment becomes crucial. Effectively the reserve is too small and impoverished to accommodate the natural processes of large herbivores as would be apparent for example in the Serengeti where large herbivores migrate over large distances.