Geodiversity assessment for geomorphosites management: Derborence and Illgraben, Swiss Alps

The paper reports on a geodiversity assessment method at the local scale based on spatial multi-criteria analysis (S-MCA). The study area consists of two geomorphosites: Derborence and Illgraben, located in the Swiss Alps and representative of different types of morphodynamics. Apart from glacial and fluvial landforms, the morphology of these two sites is largely due to extreme phenomena (rockslides, torrential processes). Both areas were incorporated in the list of Swiss geosites for their geomorphological interest. The geodiversity assessment criteria were selected and presented on five factor maps: the relief energy (relative height), the landform fragmentation, the landform preservation, the geological setting and the hydrological factor. The factor maps were aggregated using the weighted linear combination (WLC) technique. The accuracy of the final geodiversity maps of Derborence and Illgraben was verified during a field inspection. The final maps were qualitatively assessed in terms of the geodiversity value of specific areas within the selected geomorphosites. The proposed method allows assessing the intrinsic geodiversity differentiation of large geosites, in particular in protected and conserved areas (PCAs). The results can be used for purposes such as the designation of most valuable parts of the area for the preservation of certain abiotic features, spatial planning or tourism management, at least in the alpine fold mountains.