Perspectives for incorporating biomass from non-intensively managed temperate flood-meadows into farming systems

Due to their high value for biodiversity preservation, flood mitigation and nutrient retention, the re-creation of flood-meadows is presently one of the main targets in restoration projects along large central European lowland rivers. Like other semi-natural grasslands, flood-meadows depend on adequate agricultural management to fulfil these important ecological functions. To achieve this in an ecologically and economically sensible way, the prospects for incorporating management and biomass utilisation in farming systems appears to be a key issue. Differences in yield and forage quality in extensively-managed flood-meadows were studied with respect to vegetation type, site conditions, management history, species-richness and nature conservation value. The study covers the most important alluvial grassland communities in the floodplain of the northern Upper Rhine (alliances Arrhenatherion, Cnidion, Magnocaricion), which are typically ordered along an elevational gradient of increasing flooding frequency. Gradients in flooding frequency between the different grassland communities and differences between classes were clearly reflected by floristic composition in Detrended Correspondence Analysis. In contrast, there were only minor differences in terms of soil nutrient status, which are consistent with relatively small differences in yield and forage quality, particularly in the drier Arrhenatherion-communities. In Cnidion meadows, yield and fodder quality were both raised in classes of higher nature conservation value, most likely due to a shift in functional groups towards sedges, herbs and legumes. However, in contrast to hypotheses recently made by several authors, no general relationship between species-richness and productivity was found. We discuss the implications of the results for restoration practice, management strategies and agricultural utilisation of species-rich flood-meadows.