A broad conceptual model (upper portion) linking the effects of abiotic factors on biotic factors (functional trait diversity and identity), and then their joint effects on aboveground biomass (AGB) of metacommunities in global forests. The concept of metacommunities is generally and graphically highlighted (see a circle of the biotic factors), i.e., the big circle represents a metacommunity, small circle within a big circle represents a community (forest plot), and symbols within the small circle represent species with different traits (in color). The multiple linear regression model (lower portion; left-sided) shows that AGB increases with functional dominance (FunDom) and higher aridity index (AI) but decreases with higher mean annual temperature (MAT), solar radiation (SRAD), the number of plots (Nplots), community-weighted mean of conservative traits (CWMCT) and community-weighted mean of acquisitive traits (CWMAT). However, latitude (Lat), soil cation exchange capacity (CEC), soil pH (PH), functional trait diversity (FTD) and plot size (PS) possess non-significant effects on AGB. In addition, the pie chart comparison for the relative contribution (lower portion; right-sided) shows that multiple abiotic and plot factors (8 variables) contribute 45.93% (including 6.64% from plot factors) whereas multiple biotic factors (4 variables) contribute 54.07% to the explained variance (i.e., 59%) in AGB. This study supports the mass ratio effect, specifically the overruling role of tall-stature or dominant trees on AGB, at a macroecological scale, and hence, suggests that a suitable species' functional strategy is important to promote carbon sequestration in forest metacommunities that underpins human well-being.

Graphical designs by Li-Qiu Wang through instructions from Arshad Ali.

Full Open Access paper here

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