Research progress on the spatial distribution and monitoring of Benggang erosion

Abstract

Benggang erosion is a severe and widespread form of soil degradation in southern China's red‐soil hilly regions, affecting over 20 000 km ² and comprising tens of thousands of gullies. Current knowledge largely relies on the 2004–2005 national survey, which provided the first systematic dataset of Benggang locations, extents and morphological attributes across key provinces, documenting a total of 229 069 gullies covering 4386 hm ² in the seven surveyed provinces. This review synthesizes recent advances in spatial mapping and multi‐scale monitoring, from field‐based measurements (erosion pins and terrestrial laser scanning) to unmanned aerial vehicle (UAV) photogrammetry, high‐resolution satellite imagery and time series Interferometric Synthetic Apertivity Radar (InSAR), enabling the detection of both morphological features and millimetre‐scale surface deformation. We develop a comparative framework for observation methods and propose a multi‐source monitoring‐chain integrating satellite screening, UAV‐based topographic mapping, ground‐based validation and InSAR‐based activity detection. A process‐oriented indicator system linking rainfall, soil moisture and deformation is outlined to support dynamic assessment of developmental stages. This review provides a systematic, evidence‐based reference for updating national inventories, integrating AI and process‐based models and establishing threshold‐based early warning, thereby advancing risk‐informed management and predictive capability under changing environmental conditions.