Abstract: To clarify the impacts of urban development on soil microbes in parks, we compared abundance and composition of soil microbial communities along an urbanization gradient in Shanghai using real-time PCR and Illumina high-throughput sequencing. Moreover, the effects of soil chemical characteristics on microbial communities were analyzed. The results showed that the abundance and alpha diversity of bacterial and fungal communities in parks in urbanized areas were comparable to or higher than those in rural areas. Compared with the parks in rural areas, relative abundances of the phyla Nitrospirae and Verrucomicrobia in parks in the central urban areas significantly increased, while Gemmatimonadetes decreased. Relative abundance of the class Eurotiomycetes in parks in the central and developed urban areas was significantly higher than those in the rural areas. Soil chemical properties and heavy metal pollutants had significant impacts on the abundance and composition of microbial communities, but their relative importance was quite different. Soil available zinc was the most important factor shaping the composition of both bacteria and fungi in park soils. In addition, soil pH, available copper, and available magnesium were the primary drivers of soil bacterial community, while total mercury, total zinc, and available lead were more important in shaping soil fungal community composition.

Key words: urban development, microbial abundance, microbial community composition, soil property, heavy metal