The constraining effects of rocky desertification on ecosystem services in the South China karst region have diminished over time

Over the past two decades, the Chinese government has implemented extensive ecological protection and restoration programs in the karst regions of South China, mitigating rocky desertification (RD) and transforming the area into a global hotspot for greening. However, within the context of rocky desertification management, the nonlinear relationships between RD and ecosystem services, as well as their constraining effects, have not been effectively addressed. Moreover, the application of RD threshold in adaptive management of karst areas is still limited. This study focuses on various karst geomorphological regions in South China to elucidate the mechanisms by which RD impacts ecosystem services and to investigate the constraining effects and thresholds across different karst landscapes. Our results indicate that since the implementation of rocky desertification control projects, the regional ecological environment has significantly improved. The thresholds at which RD affects ecosystem services have increased over time, suggesting that its constraining effects have diminished. Among the four quantified ecosystem services, the thresholds for the impact on grain production services are lower in most geomorphological regions, indicating that RD imposes stronger constraints on grain production compared to other services. By evaluating ecological projects from the perspective of these constraining effects, this study provides a scientific basis for developing differentiated strategies for RD prevention and control.