Soil microbial diversity-function relationships are changed by human activity at a landscape scale

Background and Aims: Soil microorganisms are crucial contributors to the regulation of diverse ecosystem functions in natural ecosystems. However, the influence of land use types on the relationships between soil microbial diversity and soil multifunctionality (SMF) has been scarcely evaluated at a landscape level. Methods: A high-resolution field survey was undertaken with 228 sites (2 × 2 km2 grid each) to investigate the influence of four land uses on the relationship between soil microbial diversity (bacteria, fungi and protists) and SMF in Pinggu District, China. Results: Soil microbial diversity index and multifunctionality were the highest in orchards and natural forests compared to plantations and cropland. Also, while soil microbial diversity index and SMF were positively correlated across all land uses and in natural forests. However, this relationship was decoupled within cropland, orchards and plantations. Increases in module richness within ecological networks were also important predictors of SMF, especially in cropland and orchards. Conclusion: This study provides new insights on the impacts of land use types in changing the fundamental relationship between soil microbial diversity and function.