Data from: Functional diversity enhances, but exploitative traits reduce tree mixture effects on microbial biomass

1. Soil microorganisms play key roles in terrestrial biodiversity and
ecosystem functions. Despite recent progress in elucidating the
association between plant diversity and soil microorganisms, it remains
unclear whether the functional properties of plant mixtures might alter
this association. 2. We examined whether the effects of tree species
mixtures on soil microbial biomass were impacted by the functional
diversity (FD) and community-weighted-mean (CWM) of tree mixtures, by
conducting a global meta-analysis involving 123 paired observations of
tree mixtures and the corresponding monocultures from 38 studies in
forests. 3. We found that the tree mixture effect on microbial biomass
increased with the FD of specific leaf area (SLA), leaf N and P content,
as well as the FD based on all of these traits plus leaf dry matter
content. Meanwhile, the responses of microbial biomass to tree mixtures
decreased with the CWM of SLA, leaf N, and P content. The effects of FD
and CWM remained consistent, despite variable tree species richness, stand
age and climatic factors. 4. Our results provide a new insight that the
functional properties of plants may alter the magnitude of the association
between plant diversity and soil microorganisms.