Knowledge of below- and above- ground biomass allocation is fundamental for our understanding of terrestrial carbon sequestration and cycling in the context of global change.However, how multiple global-change factors interactively affect biomass allocation in terrestrial ecosystems remain unclear. Here, a meta-analysis was performed to examine the main and interactive effects of multiple global-change factors on below- and above-ground biomass, and root: shoot ratio (R/S) based on 1867 individual treatments in 109 studies.
Results/Conclusions
Our results showed that elevated CO2 (E), nitrogen addition (N), warming (W), irrigation (I), and their combined treatments (EN, EW, NW, ENW, and IN) all stimulated below- and above-ground biomass, while drought decreased them. The combined treatments with nitrogen addition or irrigation displayed a negative effect on R/S, while treatments with drought increased it. Across all the individual studies, additive interactions among global-change factors exhibited a predominance (81.74%) on both plant biomass and biomass allocation relative to synergistic and antagonistic ones. With increasing magnitude of biomass changes (positive or negative) induced by global change factors, additive interactions were constrained and antagonistic interactions increased, especially in EN, EW and NW. Interestingly, relative to changes in aboveground biomass, belowground one exhibited large susceptibility to global-change factors and had a greater correlation with changes in R/S. Our study highlights the importance of evaluating the global-change impacts on plant biomass allocation for terrestrial carbon cycle and provides insights for adjustment of allocation coefficient in future model prediction.