Spatial–Temporal Evolution of Ecological Network Structure During 1967–2021 in Yongding River Floodplain

Constructing a rational ecological network is crucial for balancing regional development with environmental protection. However, existing research typically emphasizes the analysis of overall patterns, lacking an in-depth exploration of the dynamic changes in key elements and the interactions between different components. Using the Yongding River floodplain as a case study, this study applied morphological spatial pattern analysis, landscape connectivity metrics, and biodiversity assessments to identify core ecological source areas. Circuit theory was used to delineate ecological corridors and analyze network evolution across four key years, while graph theory facilitated an in-depth analysis of network structural characteristics. Furthermore, key areas for ecological restoration were identified within the floodplain. We found that the number of ecological source patches in the study area has remained relatively stable, though their total area has shown a fluctuating decline, accounting for approximately 10% of the floodplain. Additionally, ecological corridors have decreased significantly from 1967 to 2021, with a marked reduction in major corridors, leading to increased resistance to material and energy flow and a corresponding decline in network connectivity and stability. More importantly, current ecological pinch points are primarily distributed in a bead-like pattern along the Yongding River channel, while ecological barriers are concentrated in the northern and eastern floodplain, often at intersections of dense road networks and ecological corridors. These critical areas of fragmentation within the ecological network are prioritized for targeted ecological protection and restoration efforts. Overall, this study advances our understanding of the spatial distribution and composition of key ecological elements within river corridor networks and offers a framework for evaluating these networks through a multidimensional optimization approach for ecological source patches. At the same time, we conducted an in-depth analysis of key fragmentation areas in the Yongding River floodplain, providing valuable guidance for future ecological protection and restoration initiatives in river corridors.