Modeling soil-erosion connectivity in drylands using a sandpile framework

Soil erosion is a major contributor to the degradation of soil resources that underpin ecosystem functioning across terrestrial systems worldwide. Yet existing erosion models often require extensive parameterization and computational resources, limiting their generalizability across spatial and temporal scales. Here, we adapt a dissipative sandpile model, incorporating spatially heterogeneous vegetation and microtopography, and test whether this minimalist framework can reproduce erosion patterns and provide mechanistic insights into connectivity-driven dynamics in drylands. We introduce a structural connectivity (SC) measure to predict erosion hotspots and find strong correlations with the landscape’s functional connectivity (FC), particularly in shrubland. Using connectivity patterns and field data, we benchmark our model against MAHLERAN, a process-based erosion model, and identify key relations between vegetation patterns, microtopography, and potential geomorphic feedback. Using generated landscapes and analyzing heavy-tailed avalanche size distributions, we explore how vegetation clustering and shrub encroachment shape erosion dynamics. We find that shrublands exhibit more frequent large-scale erosion events than grasslands, driven by the formation of convergent flow pathways. Our layered modeling strategy benchmarks simplified models against data-intensive approaches, providing complementary mechanistic insight. In particular, our findings highlight the role of pathway complexity in soil erosion and provide a computationally efficient framework for data-limited settings.