Classification of rocky desertification degrees and analysis of driving factors in typical karst regions

Rocky desertification is a major ecological problem in karst regions, driven by the combined effects of natural conditions and human activities. To investigate its spatiotemporal evolution and driving mechanisms, this study constructed a two-dimensional Rocky Desertification Index (RDI) based on the Normalized Difference Vegetation Index (NDVI) and Bare Land Index (BLI) for Liupanshui City, Guizhou Province, China, during 1987–2022. The results showed that the overall classification accuracy reached 88.16%, and rocky desertification exhibited an overall alleviation trend, with non-desertified areas expanding continuously and moderate and intensive rocky desertification decreasing significantly. Optimal Parameter-based Geographical Detector (OPGD) analysis identified land use as the dominant driving factor, with q-values ranging from 0.44 to 0.64, while its interactions with climatic and terrain factors showed enhanced explanatory power. Partial Least Squares Structural Equation Modeling (PLS-SEM) further revealed a clear shift in driving mechanisms, from natural-factor dominance before 2000 to increasing human-activity dominance after 2007. These findings provide scientific support for rocky desertification control and ecological restoration in karst regions.