Landscape metrics as a tool for evaluating scenarios for flood prevention and nature conservation

Within the framework of the project „Flood Prevention and Nature Conservation in the Weisseritz area“ („HochNatur“), a method including landscape metrics was developed and applied to assess and to compare different land use scenarios with regard to flood prevention and nature conservation. For the analysis, two sub-catchments strongly differing in land use within the Weisseritz catchment (Eastern Erzgebirge, Saxony, Germany) were selected. The first step of the evaluation procedure was a biotope assessment using three assessment criteria (naturalness, substitutability, rareness / endangerment). However, the biotope assessment did not yield any information about spatial distribution or the structural composition of the landscape. Therefore, landscape metrics were applied to analyse the structural and biotope type diversity at the landscape scale. Different landscape metrics (Shannon/Weaver diversity index, mean patch size index, Interdispersion/Juxtaposition index) and a weighting system were used to compare the different land use scenarios and the current state. The analysed catchment areas differ substantially in terms of their current state and potential measures regarding flood prevention and nature conservation depending on the location and distribution of biotope types. It was demonstrated that this method can be used for small catchment areas regardless of their land use for assessing, analysing and comparing different land use scenarios for a specific area.