Temporal changes in soil dissimilarity are driven by synergistic effects of tree types and geographical distance in city parks

Abstract

Urban parks play a crucial role in maintaining biodiversity and ecosystem functions within cities, making the study of their soil and microbial dynamics essential. This study investigates the temporal dynamics of soil properties and microbial community diversity across urban parks in Shanghai, exploring how intra-urban land-use characteristics, particularly park age and vegetation type, shape microbial community composition, with bacterial communities expected to respond more strongly to environmental homogenization and fungal communities, especially functional guilds, being more closely tied to vegetation traits. We observed distinct differences in soil physicochemical properties and microbial communities among city parks of different ages. Fungal communities maintain conserved distinction across tree types, while bacterial communities demonstrated remarkable functional and structural convergence. It is noteworthy that the changes in alpha and beta diversity exhibit inconsistent patterns across time, while the rate of convergence in beta diversity responses to intra-urbanization varies among taxonomic groups. The synergistic interaction between tree types composition and geographical distance is a key driver shaping soil microbial diversity, and neither factor alone is sufficient to account for significant diversity changes along the age gradient. Populations with high overall richness but low single-species abundance contributed more to alpha and beta diversity, including rare species and specialist species. Overall, this study highlights the importance of tree types composition in shaping microbial community diversity, providing valuable insights to complement intra-urban tree planting strategies.