Quantifying Trail-Induced Fragmentation in Protected Natural Areas Using Large-Scale GPS Trajectory Analysis

Alexander Akira Weimer , Maria Clara De Souza, Justin Abraham

Protected areas are essential for biodiversity conservation, but recreational activities can fragment habitats through trail networks. This study quantifies trail-induced fragmentation across all protected area types in Switzerland using a novel computational pipeline combining fastgeotoolkit for GPS trajectory processing and GeoPandas for spatial analysis. 3,136 hiking GPS tracks (29,563 km total trail length) and 28,686 protected area polygons covering
21,529 km2 (52% of Switzerland) were analyzed. The overall fragmentation index was 0.82% (95% CI: 0.78–0.86%), indicating that trails affect less than 1% of protected areas. However,
significant variation exists across protected area types: Alpine alluvial vegetation (1.21%), dry meadows (1.63%), and high marshes (1.87%) show the highest fragmentation, while the Swiss National Park (0.00%) remains pristine. A buffer sensitivity analysis revealed
that fragmentation estimates range from 0.82% (10m) to 4.12% (50m), with the 10m buffer providing the most ecologically relevant measure. Core habitat (areas >100m from trails) averages 86.7% across all protected areas, suggesting Switzerland’s trail network is well-managed and does not significantly fragment protected landscapes. Validation against the official Swiss trail network showed that GPS-derived trails captured 87.3% of official trails
within protected areas, confirming the representativeness of our crowd-sourced data. The highest trail densities occur in popular hiking regions including the Bernese Oberland, Valais,
and Ticino. Our methodology demonstrates a scalable, reproducible approach for monitoring recreational impacts on protected areas using open data and computational tools.