Plant Diversity Along the Urban–Rural Gradient and Its Relationship with Urbanization Degree in Shanghai, China

Abstract

Urbanization is one of the major causes for plant diversity loss at the local and regional scale. However, how plant species distribute along the urban–rural gradient and what the relationship between urbanization degree and plant diversity is, is not very clear. In this paper, 134 sample sites along two 18 km width transects that run across the urban center of Shanghai were investigated. We quantified the spatial patterns of plant diversity along the urban–rural gradient and measured the relationship between plant diversity and urbanization degree, which was calculated using a land use land cover map derived from high spatial resolution aerial photos. We recorded 526 vascular plant species in 134 plots, 57.8% of which are exotic plant species. Six spatial distribution patterns of species richness were identified for different plant taxa along the rural to urban gradient. The native plant species richness showed no significant relationship to urbanization degree. The richness of the all plants, woody plants and perennial herbs presented significant positive relationship with urbanization degree, while the richness of annual herbs, Shannon-Wiener diversity and Heip evenness all exhibited a negative relationship to urbanization degree. Urbanization could significantly influence plant diversity in Shanghai. Our findings can provide insights to understand the mechanism of urbanization effects on plant diversity, as well as plant diversity conservation in urban areas.

Impact of urbanization on soil microbial diversity and composition in the megacity of Shanghai

“…Significant changes in these phylotypes might be due to the presence of certain host plants and/or the direct human management of urban plants. In Shanghai, most ornamental plants are transplanted from other regions, and over 70% of the trees are nonnative species in sites within 11 km from the City centre (Wang et al, 2020). The positive relationships between woody plant richness and the positive indicators suggest soil microbes have been introduced with transplanted or nonnative trees (Lekberg et al, 2013).…”

“…A sampling density of 3:1 was used to sample the grids inside and outside the highly urbanized areas (Figure 1a; < 16 km radius from the Shanghai People's Square). Within each selected grid, a modified Whittaker sample site with the size of 20 m  50 m was settled on a randomly selected greenspace (Wang et al, 2020). In total, 258 sampling sites were established, ranging from 45 km in latitude and 63 km in longitude (Figure 1a).…”

“…Each sampling site was separated into 14 subplots, including two 50 m 2 , two 10 m 2 , and ten 1 m 2 subplots. All vascular plants in the subplots were identified from July to September in 2014-2017 (Wang et al, 2020). Overall, we recorded 214 woody species and 439 herbaceous species, accounting for 10% and 26% of the current plant records of Shanghai City (Ma, 2014).…”

Effects of Landscape and Local Factors on the Diversity of Flower-Visitor Groups under an Urbanization Gradient, a Case Study in Wuhan, China

“…Urbanization is a dynamic process involving dramatic and continuous changes in land use, including a decrease in bare land, an increase in the area covered by impervious surfaces, and the loss of natural vegetation [10,12,13]. In general, urbanization causes habitat loss and reduces the habitat suitability of pollinators, and consequently reduces the abundance and diversity of pollinators [14][15][16][17].…”

Study on Spatiotemporal Characteristic and Mechanism of Forest Loss in Urban Agglomeration in the Middle Reaches of the Yangtze River

“…The main reason is that China has a very effective forest fire prevention and fighting system, extinguishing many outbreaks before they spread. Forest loss caused by windstorms mainly occurs in China's southeast coastal areas, accounting for about 2% of the national forest loss [28]. Given China's annual afforestation of about 67,000 km 2 , most forest losses from fire and windstorms have been restored shortly [29].…”