Land-use type strongly affects soil microbial community assembly process and inter-kingdom co-occurrence pattern in a floodplain ecosystem

The floodplain ecosystem is crucial for facilitating or regulating regional ecological functions (biodiversity conservation, contamination filtration, soil erosion prevention, flood control and so on). The intensified use of floodplains may significantly influence the soil's potential to handle ecosystem functions by changing key biotic groups such as soil microbes. However, little is known about the response of soil microbial communities to land-use change in the floodplain. This study investigated the effect of land-use type on the community assembly process and co-occurrence network pattern of bacteria, fungi, and protists. Here, we investigated three land-use types: tender floodplain, farmland and fallow. We found that microbial composition and structure were more susceptible to land-use types rather than microbial diversity indexes. Microbial community structure was related to divergence in soil fertility. In tender floodplains and fallows, the contribution of stochastic processes to the assembly of bacteria, fungi and protist communities was higher than that of farmlands. Among the three land-use types, the tender floodplain had the most stable microbial network, whereas fallow had the least robust microbial network. Our results indicated that land-use types strongly affect soil microbial assembly processes and co-occurrence network patterns, which may provide a scientific foundation for sustainable management and conservation in floodplain ecosystems.