Does species diversity affect the function of residential greening in the Yangtze River Delta

The purpose of this study was to investigate whether high plant species diversity could increase the landscape and ecological function of residential greening in a random selection of nine cities, Ningbo, Shaoxing, Jiaxing, Hangzhou, Nanjing, Zhenjiang, Changzhou, Wuxi and Suzhou, in the Yangtze River delta. A quantitative evaluation system was used to evaluate the landscape and ecological function of green space. The relationship between landscape/ecological function and species diversity was analyzed by linear regression. The results indicated that the average Simpson’s index of the 27 surveyed residential green spaces was 8.74 ± 0.60, while the score for landscape effect/ecological function was 6.25 ± 1.42 and 2.70 ± 0.90 respectively. There was a significant correlation between vegetation species diversity and landscape function, and further investigation indicated that more tree species could have a greater effect than more shrubs and herbs. In contrast, there was no significant correlation between vegetation species diversity and ecological function. Thus, the results suggested that high plant species diversity in the majority of residential areas would only improve landscape, and not ecological, function.