POTENTIAL FOR THE DEVELOPMENT OF MARSH VEGETATION FROM THE SEED BANK AFTER A DRAWDOWN

In the inundated part of the Oostvaardersplassen, a marsh in The Netherlands, most of the emergent vegetation disappeared due to herbivory and erosion, resulting in a shallow lake. The emergent vegetation was successfully re-established by means of a drawdown. A comparable flooded marsh was studied to describe its seed bank and to find out if it was possible to make an accurate prediction of the vegetation developments after a drawdown based on the Van der Valk model on succession in wetlands. Two different zones could be distinguished in the lake. These differed mainly in the number of seeds found, not in the species composition of their seed banks. The short-term prediction that Typha latifolia would become dominant did not always match the actual pioneer vegetation that developed, several different communities developed from similar seed banks. The long-term prediction, that Phragmites australis would become dominant after four years of drawdown, was fulfilled.