Airborne laser scanning change detection for quantifying geomorphological processes in high mountain regions

Abstract. Disturbance by geomorphic processes is a key factor for current and potential plant species distributions in high mountain regions. We implemented and tested an approach for the detection, quantification, and geomorphological classification of 3D topographic change using airborne laser scanning (ALS) data. This approach is applied to two point cloud epochs (from 2006 and 2017) to identify and analyse changes related to five different process categories in a study area in the European Alps: Fluvial Processes, Rock Glacier Movement & Landslides, Channel Erosion & Debris Flow, Rockfall Release & Deposition and Vegetation & Anthropogenic Change. The results are assessed through comparison with a manually produced geomorphological map. The analysis covering the eleven-year time period provides detailed information on the magnitudes and spatial distribution of change per identified geomorphological process. The study shows that the workflow is capable of providing the fundamental basis for mapping vegetation disturbance by geomorphic activity in a high alpine site.