The goals of the subproject “molluscs” within the inter-disciplinary research project “Indicator systems for the characterisation and prediction of ecological changes in floodplain systems” were: – to develop further existing mollusc-based indicator systems of site quality and to test their transferability, – to characterise grassland sites within the recent floodplains of three study areas along the Elbe River, – to analyse the relationships between indicator species-/groups and abiotic parameters, – to compile and use selected species traits in the analytical process. The results clearly show several characteristic species groups related to the hydrology of the sites (i.e. inundation and desiccation regime) and on to the degree of agricultural use. These dependencies can be interpreted by the simultaneous analysis of the species traits. “Models” are proposed, that are applicable to nature protection measures at the landscape scale.