Soils in floodplains and riparian zones provide important ecosystem functions and services. These ecosystems belong to the most threatened ecosystems worldwide. Therefore, the management of floodplains has changed from river control to the restoration of rivers and floodplains. However, restoration activities can also negatively impact soils in these areas. Thus, a detailed knowledge of the soils is needed to prevent detrimental soil changes. The aim of this review is therefore to assess the kind and extent of soil information used in research on floodplains and riparian zones. This article is based on a quantitative literature search. Soil information of 100 research articles was collected. Soil properties were divided into physical, chemical, biological, and detailed soil classification. Some kind of soil information like classification is used in 97 articles, but often there is no complete description of the soils and only single parameters are described. Physical soil properties are mentioned in 76 articles, chemical soil properties in 56 articles, biological soil properties in 21 articles, and a detailed soil classification is provided in 32 articles. It is recommended to integrate at least a minimum data set on soil information in all research conducted in floodplains and riparian zones. This minimum data set comprises soil types, coarse fragments, texture and structure of the soil, bulk density, pH, soil organic matter, water content, rooting depth, and calcium carbonate content. Additionally, the nutrient and/or pollution status might be a useful parameter.

Since the Water Framework Directive (WFD) came into force in 2000, data on the hydromorphological quality have been collected for all rivers in Europe. In Germany, a reference-based classification scheme is used (LAWA 2000) for hydrological assessment. The question arises whether this method can compensate sufficiently for a change of ecoregion. In our study of the Hase River in NW Germany, the frequency of the river classes was compared between two ecoregions (Lower Saxonian Mountains vs. Northwest-German Lowlands). In the lowlands, the evaluation shows a significantly higher proportion of class 5 river sections. This can mainly be attributed to the main parameters, longitudinal section, riverbed structure and bank structure. While the bad results in the longitudinal section and bank structure can be explained by changes in geology and anthropogenic pressures, the evaluation scheme cannot sufficiently compensate for changes in the riverbed structure. This problem is aggravated by the inconsistent implementation of the evaluation scheme in Germany, where the federal states use different approaches with regard to section length. Using 100 m sections throughout the river course can lead to severely underestimating the number of structures. Further improvement and standardization in the evaluation scheme seem to be necessary for the adjustment of the field survey method to different ecoregions in Germany.

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