Geodiversity mapping in alpine areas

Geodiversity mapping has become an established tool for assessing the value of the abiotic part of the landscape. We present two methods, which have been developed in the mountains of the State of Vorarlberg (Austria), but have a wider application in alpine areas. The first is a region‐wide index‐based mapping of Vorarlberg that is designed with the purpose of generating, in a preliminary evaluation, an inventory of clusters of high geodiversity. The second method comprises detailed geomorphological mapping at a local scale and supports landscape planning and management by identifying potential geoconservation sites. The latter approach also enables the evaluation of the relationship between geodiversity and biotopes. We generated a geodiversity (index) map of Vorarlberg in a GIS showing the spatial distribution of a combination of six abiotic factors (subindices) expressed as numeric values in five classes. Both conventional and unconventional data sets were used, ranging from field‐based geological maps to digital data sets acquired in airborne LiDAR surveys. In this approach, high geodiversity is found more often in areas of combined complex topography and varied geological substrata. The geodiversity map can be used to rapidly assess the occurrence of clusters of high geodiversity, which subsequently can be evaluated in detail using a landform‐based approach. As an example of the latter, we present the case study of a small area near the village of Au in central Vorarlberg, Austria. Using a detailed area‐covering polygon‐based morphogenetic map as the basis for the assessment of the Au West area, the various classes of the legend were weighted and ranked in an automated GIS procedure with four factors: scientific relevance and frequency of occurrence (primary factors) and vulnerability and disturbance (secondary factors). Three levels of importance for geoconservation potential are differentiated (low, medium and high significance) and displayed in a map on which the highly ranked units are identified as potential sites for geoconservation. Comparison of the morphogenetic types and existing biotope data in the case‐study area suggests that most biotopes occur together with specific morphogenetic types. It appears that the distinction between “wet” and “dry” mass‐movement processes is an important factor, together with slope steepness and material properties, for effectively characterizing the natural biotopes