Optimization of ecological network to improve water conservation services in the Nianchu River Basin

Against the backdrop of water resource depletion in the Qinghai-Tibet Plateau, water conservation services (WCS) have emerged as critical ecosystem services warranting attention. Adjusting the ecological network (EN) structure and optimizing topological relationships among landscape elements are instrumental in facilitating ecological processes, constituting an effective approach for enhancing WCS. We employed the Integrated Valuation of Ecosystem Services and Tradeoffs model to simulate the WCS value in the Nianchu River Basin and used the Minimum Cumulative Resistance model in combination with the Linkage Mapper to construct an EN. Through topological analysis based on complex network theory, we examined the EN topology and identified ecological pinch points and barriers by applying circuit theory. According to the correlation between EN topology and WCS, and taking into account local vegetation restoration potential, we ultimately optimized the EN to enhance the WCS value. The results revealed a positive correlation between the WCS value and betweenness centrality (r = 0.86, p < 0.01) of forest patches, as well as with the clustering coefficient of grassland patches (r = 0.44, p < 0.05). Following the optimization of key areas with restoration potential, we enhanced the EN structure by adding six new patches, eliminating four redundant corridors, and establishing 11 new corridors. The optimized EN demonstrated enhanced stability in robustness tests, indicated by a reduced slope of edge recovery against malicious attacks (from -0.0224 to -0.0199) and an increase in the WCS value of 630,311.6 m³. This study highlights the importance of landscape spatial structure in enhancing ecosystem services, providing valuable insights for sustainable water resource management in the ecologically sensitive regions of the Qinghai-Tibet Plateau.