The restoration of fens in the Netherlands

The present paper reviews the major environmental problems in Dutch aquatic and semi-terrestrial fens: desiccation, (internal and external) eutrophication, acidification, habitat fragmentation and intoxication. It discusses both the positive and the negative consequences of the restoration measures taken in Dutch fens, and strongly emphasises the biogeochemical and biological processes and factors responsible for the deterioration of plant and animal communities in fens. Only with the knowledge of these key processes and factors are optimal restoration and management measures possible. Finally, important gaps in knowledge are pointed out and a call for new research is made.