Climatic and edaphic factors affecting soil bacterial community biodiversity in different forests of China

The dominant factors influencing forest soil bacterial richness and diversity are still obscure. In this study, a meta-analysis method was employed to clarify the different patterns of forest soil bacterial community biodiversity in China and to reveal how climate and soil factors shape these patterns. In total, 105 groups of soil microbial data were collected from 47 study sites, covering four types of forests: deciduous broad-leaved forest (DBF), coniferous forest (CF), coniferous and broad-leaved mixed forest (CBF), and evergreen broad-leaved forest (EBF). Natural forests (NFs) covered approximately 47% of the sites, and the others were planted forests (PFs). The soil bacterial community biodiversity showed some differences among the different forest types, and the Chao1 index of the soil bacterial community was highest in CBF. The richness and diversity of soil bacteria in PFs were significantly higher than those in NFs. However, the MAT and MAP showed closer relationships to the bacterial community in NFs than in PFs. In addition, the structural equation model (SEM) indicated that bacterial richness (i.e., the Chao1 index) was positively correlated with soil pH and total phosphorus (TP) and negatively correlated with soil organic carbon (SOC). The soil bacterial diversity (Shannon and Simpson indices) was positively correlated with SOC, TP and soil organic matter (SOM). Overall, soil pH, TP and soil carbon served as the most important edaphic factors affecting forest soil bacterial community biodiversity.