Linking street-level greenery to environmental microbial diversity : A multiscalar analysis in the Taipei metropolitan area

Urbanization has led to a significant reduction in green spaces, altering microbial habitats and potentially contributing to the growing prevalence of immune-mediated diseases. Urban greenery may serve as a reservoir for more diverse environmental microbiota, yet the links between street-level vegetation and environmental microbial diversity remain poorly understood. This study investigates how the visibility of greenery, measured through the Green View Index (GVI), relates to microbial richness and Shannon’s diversity across urban habitat gradients in the Taipei metropolitan area. Environmental DNA samples and Google Street View panoramas for calculating GVI were collected from three sublocation types: biodiversity hotspots featuring urban green spaces, residential building entrances, and pavements linking biodiversity hotspots and entrances. Our findings show that biodiversity hotspots support greater microbial diversity, and significant GVI–microbial correlations occur only in biodiversity hotspots, not in pavements or entrances. This positive correlation observed in biodiversity hotspots suggests that street-level vegetation can reflect the diversity of environmental microbial communities. These results highlight the importance of incorporating green infrastructure into urban planning to enhance microbial habitat heterogeneity and promote microbial diversity. As urbanization continues to sever citizens’ contact with nature, this initiative helps maintain the environmental microbiota essential for immune regulation and support public health. Future research should incorporate longitudinal and cross-seasonal studies to evaluate the durability of GVI-microbial relationships, examine the influence of vegetation types and structural complexity, and explore how urban greenery can act both as a scientific indicator and a public engagement tool in biodiversity-aware urban design.