Urban Green Corridors: Plant Biodiversity and Pathways for Nature-Based Solutions in Perth and Beijing

This paper shares preliminary results of urban green corridors plant biodiversity study in Perth (Western Australia) and Beijing (China). Urban green corridors are essential linear greenways that connect different types of urban green spaces. Urban green corridors support biodiversity, provide species movement, and enhance recreational functions and aesthetics. Our research examined three typologies of urban green corridors: street plantings, waterway plantings, and railway-adjacent green spaces. Plant biodiversity was analyzed using a literature review, mapping transects involving floristic and vegetation fieldwork surveys, and comparative analysis. One of the goals of this research was to analyze urban green corridors’ evolution to compare the two cities' biodiversity conditions and propose several Nature-based Solutions for Perth and Beijing. Perth was studied along an east-west transect to best sample the existing topography. In contrast, Beijing was analyzed along a north-south transect that followed the ancient city’s Central Axis. In both case studies, surveys were conducted at 14 sites across the three types of urban green corridors. Analysis of plant dispersal revealed the dominant role of autochory and anemochory (wind) seed dispersion mechanisms in both cities. In Perth, life form (for both planted and spontaneous plants) and the analysis of species origin and richness demonstrated that planted trees and shrubs were mostly native species (56% and 62%, respectively), with species selection dependent on stakeholders’ preferences. The groundcover layer was originally planted with lawns but then left to spontaneous succession and is now 100% composed of non-native plants, predominantly annuals. Perth streets also had the highest species richness among the three urban green corridor typologies. However, in Beijing’s urban green corridors native species dominated, comprising 61% native trees, 63% native shrubs, 88% perennials, 71% annuals, and 88% vines, calculated within each life form. Findings indicate that there is potential to restore urban green corridors’ spatial structure and plant composition using the capacity of native spontaneous plants in Beijing. Whereas, in Perth, limited options to return endemic native Western Australian plants to urban green spaces exist. In Beijing, the emphasis should be on increasing plant diversity (native and non-native) in all spatial layers, while in Perth, mixed native and non-native pioneer plants in understorey layers could be used. The next step in this research is to suggest design scenarios for biodiversity-friendly Nature-based Solutions for urban green corridors in both cities. In so doing, we may develop a potential blueprint for restoring ecosystems and enhancing biodiversity resilience.