Seasonal variations in soil physicochemical properties and microbial community structure influenced by Spartina alterniflora invasion and Kandelia obovata restoration

Spartina alterniflora invasion has initiated one of the greatest changes to occur in coastal wetlands in China, and eco-logical replacement using mangrove species such as Kandelia obovata is an effective method for controlling these in-vasions. The effects of S. alterniflora invasions and subsequent K. obovata restorations on soil microbial community structures in different seasons are still not fully understood. In this study, soil samples were collected from six veg-etation types (unvegetated mudflat, invasive S. alterniflora stands, one-/eight-/ten-year K. obovata restoration areas, and native mature K. obovata forests) in summer and winter. The variations in the soil microbial community struc-ture between the vegetation types across two seasons were then characterized based on 16S rRNA gene sequencing, and the physicochemical properties that shaped the microbial communities were also determined. The invasion and restoration processes significantly influenced microbial community diversity, composition, and putative functions in different seasonal patterns. Microbial communities from a ten-year restoration area and a native mature K. obovata area shared more similarities than other areas. In both seasons, the key environmental factors driving microbial community included total carbon and nitrogen content, the ratio of carbon to nitrogen, and the soil pH. In addition, total sulfur and total phosphorus contents significantly contributed to structuring microbial communities in summer and winter, respectively. This study provides insights into microbial diversity, composition, and functional profiles in association with physicochemical impacts, with the aim of understanding microbial ecological functions during the invasion and restoration processes in wetland ecosystems. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The invasion of Spartina alterniflora and subsequent Kandelia obovata restoration have significant impacts on soil microbial community structures in different seasons. Ten-year restoration areas and native mature Kandelia obovata areas show more similarities in microbial communities. Key environmental factors driving microbial community include total carbon and nitrogen content, carbon-to-nitrogen ratio, and soil pH.