Functional identity regulates aboveground biomass better than trait diversity along abiotic conditions in global forest metacommunities

Although several studies have identified the effects of functional trait diversity (FTD) and/or identity, i.e. community-weighted mean (CWM) a trait, on aboveground biomass (AGB) along abiotic conditions, these AGB in global forest metacommunities are still largely unexplored. Here, we modelled (i.e. climate, soil and plot physical conditions) biotic [i.e. FTD, CWM conservative traits (CWMCT), acquisitive (CWMAT) dominance (FunDom; based plant maximum height or diameter)] factors 76 (from 24 studies). Using multiple linear regression models piecewise structural equation modeling (pSEM), tested hypothesis that both regulate but mass ratio mechanism underpins forests better than niche complementarity mechanism. We found contributed 45.39% 54.07%, respectively, to explained variance (R2 = 0.59), as such, shaped FTD 0.42–0.48), CWMCT 0.33–0.36), CWMAT 0.27–0.33) FunDom 0.59–0.61) through divergent effect sizes directions. The final best-fitted pSEM showed increased (? 0.49) ?0.35) ?0.11) decreased 0.52) compared negligible 0.04). This study supports effect, specifically overruling role tall-stature dominant trees AGB, at macroecological scale, hence, suggests suitable species' strategy is important promote carbon sequestration human well-being. expect our will advance field biodiversity–ecosystem functioning scale by using metacommunity concept approach.