Collembola species composition and diversity effects on ecosystem functioning vary with plant functional group identity

► We study the effect of Collembola composition and diversity on ecosystem functions. ► We found idiosyncratic and context dependent effects of Collembola diversity (CD). ► CD and composition effects depended on plant functional group identity. ► Collembola response traits did not conform to effect traits. ► CD effects on root depth distribution are likely to modify plant competition.