Construction of composite blue-green ecological network of Wuhan City based on complex network theory

The construction of composite blue-green ecological network is the key for network nodes to play multiple functions, which is of great significance for enhancing regional ecological functions and landscape quality. Based on the complex network theory, we proposed a framework for building a composite blue-green ecological network. From the perspectives of structural composite and functional composite, we integrated the ecological green network targeting bird and mammal species with the blue network composed of natural and semi-natural water ecological networks to construct a composite blue-green ecological network in Wuhan City, and quantitatively evaluated the resilience of the composite blue-green ecological network. The results showed that the overlap ratio of blue nodes and green nodes was high and the composite potential was great. The composite blue-green nodes were the core of ecological protection, accounting for 92.6% of the total area, and were often surrounded by a single blue or green node. The overall composite blue-green ecological network exhibited scale-free characteristics, and the composite blue-green ecological network within the central urban area exhibited small-world characteristics. From the perspective of network structural resilience analysis, the overall connectivity of Wuhan's composite blue-green ecological network was average, and the connectivity between blue-green nodes was lower than that of single network nodes, so targeted protection was needed. The study would provide a basis for urban planners to formulate effective optimization strategies for the composite blue-green ecological network from an overall perspective, and enhance the synergistic supply capacity of urban blue-green resources.