Conversion of broadleaf forest to plantation changes the assembly process and composition of soil microbial communities in a subtropical forest

Aims

Conversion of natural forests to plantations would change aboveground biodiversity and soil physiochemical properties. However, how forest conversion changes soil microbial community structure and assembly process has not been well addressed.

Methods

We characterized the abundances, diversity, assembly processes, and structures of bacterial and fungal communities from a broadleaf forest (BLF) and two plantations (Moso bamboo plantation, BP; Chinese fir plantation, CP) that converted from the BLF.

Results

Conversion of broadleaf forest to plantations significantly decreased soil organic carbon and total nitrogen concentrations (P < 0.05). Bacterial and fungal abundance and diversity in BP and BLF were significantly (P < 0.05) higher than those in CP. The dominant phyla (Acidobacteria and Proteobacteria) and predicted function (Amino acid metabolism and carbohydrate metabolism) of bacterial communities were weakly changed, whereas those of fungal communities were significantly altered by forest conversion. The habitat niche breadth of BP was significantly higher than that of CP and BLF (P < 0.05) due to the broader range of resource states (available P and K) in the BP soil. Forest conversion enhanced the deterministic process but weakened the stochastic assembly process of both bacterial and fungal community assembly. Random forest model demonstrated that both bacterial and fungal community assembly were the most important driving factors regulating their community structures by forest conversion.

Conclusion

Conversion of broadleaf forest to plantations markedly altered soil bacterial and fungal community structures and enhanced their deterministic community assembly processes, deepening the understanding of the impacts of ecological processes in forestry management.