Abstract: Understory herbaceous plants are a major conservation layer for the biodiversity of urban forest ecosystems. Due to their high plasticity and sensitivity to disturbance, herbaceous plants can effectively indicate the adaptation strategy of urban vegetation to urbanization. In this study, we surveyed 398 plots in 16 sites of woodland located along a gradient of central city area, suburb area, and rural area in Shanghai, and analyzed the flora characteristics and diversity pattern of herbaceous plants in urban forests. A total of 144 herbaceous species were recorded, which belonged to 47 families and 118 genera. Among them, 74 species of perennial herbs were recorded, contributing over half of the total species (51.39%). The distribution type of genus and species covered 18 and 12 geographical distribution types and subtypes, respectively, and most were temperate and tropic species. There were 28 alien species, accounting for almost 20% of the total. Both specie richness and diversity index of herbaceous plants were deceased firstly and then increased along the urban-rural gradient. Species composition in central city sharply contrasted to that in suburban sites, but was quite similar to that in rural sites. Our results clarified the distribution pattern and variation of the diversity of herbaceous plants along urban-rural gradient in Shanghai, and provide a theoretical basis for researches on the interaction between urbanization and urban forest and scientific reference for the management department to makepolicy.

Key words: urban forest, plant flora, herbaceous plant diversity, urban-rural gradient.