Zoning Management Based on Spatiotemporal Evolution of Ecological Risk: Spatial Network Analysis of Riparian Zone in Lanzhou–Baiyin Metropolitan Area of the Yellow River Basin

The upper Yellow River basin is a classic ecologically vulnerable area, characterized by acute human–land conflicts. The rapid pace of urbanization drives landscape fragmentation, which severely threatens regional sustainability and ecological security. Given the difficulty of using a single indicator to fully diagnose the relationship between ecological function and risk, this research establishes a spatial diagnostic framework that uses ecosystem service value (ESV) to measure functional output and landscape ecological risk (LER) to indicate structural vulnerability. Utilizing land use data from 1990 to 2020, we quantified, for the first time at a 250 m grid scale, the spatiotemporal evolution of ESV and LER in the riparian zone of the Lanzhou–Baiyin metropolitan area (LBMA). The findings reveal concurrent declining trends in both ESV and LER, which signal not ecological improvement but rather systemic degradation towards lower functionality and lower ecological risk. Bivariate LISA clustering was used to identify four categories of ecological regulation zones, offering a spatial foundation for implementing differentiated governance. Building on the four-zone typology, this research further proposes a tiered control strategy encompassing strict protection, urgent restoration, and built-up area optimization, highlighting its advantages compared to conventional single-indicator management. This framework links spatial pattern diagnosis with ecological governance actions and also provides an analytical tool for understanding and managing the security of riparian ecosystems under similar pressures.