Evaluation of floodplain rehabilitation: a comparison of ecological and policy-based biodiversity assessment.
De Nooij, R. J. W.; Hendriks, H. W. M.; Leuven, R. S. E. W.; Lenders, H. J. R.; Nienhuis, P. H.
This study evaluates the effects of ecological rehabilitation on biodiversity in floodplains along lowland rivers in the Netherlands, using two different approaches. Species richness was compared with a policy and legislation based index, calculated by means of BIO-SAFE. BIO-SAFE is a valuation model that incorporates only protected and endangered river species, derived from Red Lists, the European Habitats directive, the European Birds directive and the conventions of Bern and Bonn. The study included higher plants, birds, mammals, herpetofauna, odonates and butterflies. In some cases, biodiversity in the floodplains significantly increased after rehabilitation. However, the outcome of the evaluation differs per taxonomic group and approach. The results show positive temporal trends with respect to species richness of higher plants, herpetofauna and odonates, and to a lesser degree mammals and butterflies. The policy and legislation based index increased to some extent, but not significantly, for higher plants, herpetofauna and butterflies. Correlation between species richness and policy-based values was found in all sites for birds, herpetofauna, odonates and, to a lesser degree, higher plants. For higher plants, positive as well as negative correlations were found, depending on the site. Based on these results, we argue that an ecological approach and a policy based approach yield complementary information. Therefore, it is recommended to apply a multi-approach methodology in monitoring and evaluation of restoration projects.