Land spatial optimization in ecologically fragile regions of the Lanzhou Xining urban agglomeration based on a multidimensional ecosystem framework

Against the backdrop of increasing global pressures on ecosystem security, elucidating the synergistic evolutionary mechanisms among multidimensional ecosystem functions is critical for enhancing spatial governance and ecological resilience in ecologically fragile regions. Utilizing the Structure-Resilience-Activity-Services (SRAS) framework, this study evaluates the spatiotemporal evolution of ecosystem functions in the Lanzhou-Xining Urban Agglomeration (LXUA) from 2005 to 2020. It quantitatively examines the collaborative and conflicting relationships among the SRAS subsystems, determines the primary determinants shaping these interactions, and classifies the dominant ecosystem function types to guide targeted spatial optimization strategies. The principal results include: (1) Significant spatial heterogeneity exists among the SRAS subsystems, with high ES and ER values concentrated in central hilly areas, whereas high EA and ESs prevail in areas characterized by dense vegetation cover and abundant water resources. (2) The ecosystem coupling coordination degree (CCD) exhibits significant regional disparities yet demonstrates a steady overall upward trend, with its spatial pattern evolving from an initial "east-high/west-low" structure to a "central-high/peripheral-low" configuration. (3) Factors such as slope, river network density, and road network density significantly enhance ecological synergy, whereas land urbanization and economic growth exert distinct inhibitory effects. (4) The dominant ecosystem function type transitions from single-function dominance toward multifunctional integration, characterized by the emergence of comprehensive high-functionality clusters (CHFs), signifying enhanced synergy among ecosystem functions. This study provides theoretical guidance for coordinated spatial optimization in ecologically fragile regions.