Tree-species-specific effects on soil microbial community composition in subtropical southeastern China
As a dynamic driver of soil nutrient cycles, soil microorganisms are a key component in ecosystem functioning. Soil microbes are strongly affected by multiple factors including abiotic characteristics and plant species characteristics. Although there is a growing body of literature on how specific tree species, and the chemical and growth traits of those species, shape or interact with microbial communities, there have been few comprehensive studies. The aim of our study was to explore how the soil microbial community responds to tree species differences as well as tree growth traits in a species-rich subtropical setting in southeast China. We analyzed microbial community structure (PLFA) in association with 32 different tree species varying greatly in growth traits and other characteristics at the Biodiversity and Ecosystem Functioning Experiment (BEF-China project). For each tree species, we sampled soil in association with 3 individual trees grown in monoculture (24 x 24 meter plots). We then compared our microbial community analysis to growth patterns (deciduous or evergreen) and tree growth basic characteristics measured from each individual tree, including total height, crown area, breast height diameter, and various other traits. Basic soil physical and chemical parameters were also measured for plot background information.
Our preliminary results show that microbial community structure more than biomass were altered by different tree species. Specifically, there was a much lower fungal to bacterial ratio in association with evergreen species, which typically grow more slowly and have a different canopy structure than deciduous species at our sites. Microbial biomass also changed significantly between different tree species but there was no clear pattern to those changes. Soil characteristics play important roles on influencing the composition of microbial community, especially soil pH. We conclude that soil microbial community structure is indeed influenced by both individual tree and species-wide growth traits, that together shape forest soil community structure more than total microbial growth.