Exploration of soil microbial diversity and community structure along mid-subtropical elevation gradients in southeast China

Climate change is altering the abundance and distributions of natural communities in mountainous ecosystems, but the variations of soil microbial communities and their driving factors along elevation gradients at high altitudinal mid-subtropical zones have received limited attention. Such information is needed for a comprehensive understanding of the ecosystem’s response to intensifying climate changes. In this study, using Illumina sequencing, we investigated the shift in soil microbial diversity and community composition at eight evergreen broadleaf forest sites, which ranged from a low of 550 to a high of 1038 m above sea level (m a.s.l.) on Wuyi Mountain in Southeast China. Significant (p < 0.05) differences were observed only in the community structure of bacteria and fungi between the low and high elevation levels of forests, but not in their alpha-diversity indices. Soil bacterial diversity was significantly correlated with plant Shannon index. Likewise, plant richness and diversity modified soil bacterial community structures along the two elevations and were the best predictors. Soil pH was the main edaphic factor driving the fungal diversity across elevations, whereas inconsistency in the fungal trophic mode did not allow the identification of a determinant factor for soil fungal community structure. The variations of the predominant fungal trophic guilds, such as the symbiotrophs and pathotrophs, along elevation gradients were due to the plant richness and diversity prevailing at the low and high elevation levels of forest sites. The findings of this study reveal the soil microbial community dynamics and the local regulators across elevations on Wuyi mountain.