Construction of “Biomigration − Regional Cooling” Multi-functional Ecological Network in Wuhan Urban Agglomeration

Objective Rapid urbanization has encroached on large ecological spaces, causing ecological issues like biodiversity loss, heat island effect, and flooding. To address this, ecological networks composed of source sites, corridors, and stepping-stone patches are proposed to restore landscape connectivity and integrity, thereby ensuring ecological security. However, these networks have primarily focused on biodiversity conservation, neglecting other benefits to humans. This research, therefore, constructs a multifunctional ecological network in Wuhan by combining a biomigration network and a regional cooling network. This network is used to identify key areas for ecological restoration and protection, with a view to offering a reference for landscape conservation.

Methods In this research, the construction and optimization of the multifunctional network are divided into four steps. 1) Identification of two types of source patches. Based on the land cover and land surface temperature (LST) of Wuhan urban agglomeration, the research screens the biodiversity source sites and regional cold island source sites by morphological spatial pattern analysis (MSPA) and landscape connectivity. 2) Construction of two types of resistance surfaces. Based on land use type, elevation, slope, distance from road, distance from construction land, normalized difference vegetation index (NDVI) and other data, the resistance values of biomigration and cold island diffusion are calculated respectively, and raster resistance surfaces are generated in ArcGIS. 3) Based on minimum cumulative resistance (MCR) and circuit theory, biomigration corridors and regional cooling corridors are generated respectively by using the Linkage Mapper toolbox. 4) Two kinds of corridors are overlapped to form a multifunctional ecological network pattern, based on which the key areas for ecological protection and restoration are identified in Wuhan urban agglomeration.

Results In this research, Wuhan urban agglomeration is taken as the research area. Based on land cover data, satellite remote sensing data and other sources of data, and by integrating the methods of MSPA, landscape connectivity analysis and surface temperature inversion, 22 biodiversity and 27 regional cooling sources are identified, both of which are distributed in the northeastern and southern parts of the research area. Based on the MCR model and circuit theory, the multifunctional ecological network pattern of Wuhan urban agglomeration is constructed with the help of Linkage Mapper toolbox, including 44 biomigration corridors and 51 regional cooling corridors. Finally, by identifying the intersections, pinch points and obstacle points of the dual networks, the key areas for ecological restoration and protection of national land space under the perspective of multifunctional ecological network are located, including 7 intersections of the dual networks (biomigration network and regional cooling network), 85.4 km² of pinch points and 724.9 km² of obstacle points in the biomigration network, and 50.1 km² of pinch points and 926.6 km² of obstacle points in the regional cooling network.

Conclusion Aiming to further enhance human well-being through ecological network, this research integrates the biomigration network and the regional cooling network into a cohesive multifunctional ecological network framework. This integrated network sustains the regular functioning of diverse ecological processes by interlinking the supply sources of various ecological functions, thereby amplifying the protective benefits of species habitats across urban and rural landscapes and augmenting the thermal comfort of human settlements. Additionally, the overlay of the two types of ecological corridors respectively corresponding to the aforesaid two networks substantially enhances the overall connectivity and stability of the ecological network pattern. In conclusion, this research proposes a strategic planning approach for ecological conservation and restoration, aimed at fostering the connectivity of a complex functional ecological network. This strategy encompasses the protection of existing ecological sources, the cultivation of potential sources, the restoration of impediments within the dual networks, and the safeguarding of critical pinch points and intersections. The findings of this research hold significant implications for the ecological security and sustainable development of Wuhan urban agglomeration, offering a reference for the construction of large-scale multifunctional ecological networks.