Evaluation of plant community composition and ecological benefits based on six urban greenway plant species

With the acceleration of urbanization, urban greenways, as an important part of urban ecosystems, play a crucial role in maintaining ecological balance and enhancing urban environmental quality through the diversity and structure of their plant communities. This study analyzed 30 sample sites from 10 urban greenways in Minhang District, Shanghai, focusing on 4 biodiversity indices (SRI, SDI, SWDI, SE) and 5 ecological benefit indicators (microclimate adjustment, negative oxygen ion provision, PM2.5/PM10/TSP reduction, noise reduction, wind protection). The results showed that mixed vegetation types (MDEBF and MCBF) had significant advantages in biodiversity, their SRI reached 11.82 ± 1.37 and 13.00 ± 0.00, SDI reached 0.47 ± 0.05 and 0.52 ± 0.11, SWDI reached 0.81 ± 0.08 and 0.87 ± 0.20, and SE reached 0.63 ± 0.05 and 0.65 ± 0.14, all significantly higher than other types (P < 0.05). In terms of ecological benefits, MDEBF and MCBF performed more prominently: MDEBF had an average cooling rate of 22.75%, negative oxygen ion CI enhancement rate of 62.45%, and PM10 reduction rate of 13.58%; MCBF had a PM2.5 reduction rate of 14.04% and wind speed attenuation rate of 50.97%, which were better than single vegetation types. In contrast, monoculture evergreen broad-leaved forest (EBF) performed relatively poorly in both biodiversity (the lowest SRI of 5.83 ± 1.28 and SWDI of 0.20 ± 0.03) and ecological benefits. In addition, structural characteristics of plant communities, such as mean canopy width and mean sub-leaf height, were significantly correlated with their ecological benefits (P < 0.05). The results of the study provide a scientific basis for optimizing the plant configuration of urban greenways and enhancing their ecological functions, which can help promote sustainable urban development.