Distribution patterns and traits of weed communities along an urban–rural gradient under rapid urbanization in Shanghai, China

Abstract

In order to better understand the effects of urbanization on weed communities, the distribution of weed communities in Shanghai, China, was systematically investigated. The diversity of weed communities and four environmental factors, including the relative light intensity, soil moisture, soil compaction and soil pH, were measured in 1375 plots along an urban-rural gradient. The species diversity indices in each area along the urban-rural gradient were compared by using a one-way ANOVA. The weed communities were identified by using clustering methods that were based on relative dominance information. A canonical correspondence analysis was used to reveal the relationships between the species composition and the environmental factors at the community level and the Spearman's rank correlation test was used to test the relationship between the number of weed communities and each environmental factor. A total of 183 species, belonging to 41 families and 123 genera, was recorded. It was found that the species richness, Shannon-Wiener diversity index and Pielou evenness index followed a unimodal curve along the urban-rural gradient. The 1375 plots were divided into 133 weed community types. All four environmental factors significantly affected the species composition of the weed communities, but only soil compaction had significant effects on the number of weed communities. It was concluded that the diversification of habitat type and environmental change along the urban-rural gradient led to more weed communities in rural areas and fewer weed communities in urban areas. Based on the species' habitats and distribution patterns, the weeds were divided into "widespread", "urban" and "rural".

Phylogenetic and functional structures of plant communities along a spatiotemporal urbanization gradient: Effects of colonization and extinction

“…To identify the floristic changes of ruderal plant species along spatial and temporal urbanization gradients, occurrence data were obtained from two of our previous studies in Shanghai city and Harbin city (Chen et al., ; Tian et al., ), two metropoles experiencing rapid urbanization in China. Both studies indicated that the ruderal species composition changed significantly along urban–rural gradients.…”

“…As spontaneous plants in urban area, ruderal plant species have high sensitivity and a short lifecycle, and thus can respond to the urban habitat heterogeneity and rapidly adapt to the habitats by changing their morphology, physiology and behavior. Thus, ruderal species are the optimally indicators for urbanization (Chen, Wang, Liang, Liu, & Da, ; Tian, Song, & Da, ). In this study, we analyzed the phylogenetic and functional structures of ruderal plant species in two Chinese cities and evaluated the differences among colonists/extinct species and residents using time series (before–after urbanization) and spatial comparison approaches (urban–rural urbanization gradients).…”

Plant species composition in an international trading port and residential areas of Kobe, Japan

“…weeding). For example, winter annual species characterised trampled sites in Chiba, Japan (Kitazawa & Ohsawa ) and urban vegetation in Shanghai, China, because they can complete their life history within a short time period, allowing them to avoid human disturbance (Tian et al ).…”

Preliminary results of the tolerance to inorganic contaminants and phytoextraction potential of twelve ornamental shrub species tested on an experimental contaminated site

“…Shanghai lies in the transitional zone between subtropical and warm temperate zone and has a subtropical monsoon climate. Its average annual temperature is 27.8 °C with an annual rainfall of 1457.9 mm, of which 60% is concentrated in the rainy season from May to September (Tian et al 2015). The soil of the experimental site has been described previously and is a silty clay loam with an elevated pH of 8 (Wu et al 2012).…”