Seasonal variations in soil microbial communities under different land restoration types in a subtropical mountains region, Southwest China

Soil microbial community is an important indicator for understanding the effects of land restoration on soil quality and ecosystem development. Natural vegetation restoration types (shrubland and natural secondary forest) and plantation forests (Pinus forest and Eucalyptus forest) were selected to investigate the effects of land restoration models and seasons (dry and wet seasons) on soil microbial communities using phospholipid fatty acid analysis (PLFA). The results of two-way ANOVA and PERMANOVA test demonstrated that the land restoration type and season had significant effects on the concentrations of PLFA biomarkers. Significantly higher concentrations of all groups of PLFAs were found in natural secondary forest than in shrubland and plantation forests, suggesting that plant species-specific differences in quality and quantity of litters, root exudates and the soil properties influence the soil microbial community composition. Relative to the wet season, increases of biomasses of fungi, actinomycetes, AMF, and gram-positive bacteria in SL and NSF in the dry season were significant. The result of redundancy analysis showed that soil organic carbon and soil moisture significantly explained the variation in response of soil microbial communities to season and land restoration type in this region. Our finding indicates that heterogeneity of soil microbial response to time and vegetation must be considered in assessment of ecosystem functions and services under different land restoration types.