Meta-analysis of woody plant diversity and aboveground biomass stock co-benefits across Amazon agroforestry systems

Understanding how biodiversity and aboveground biomass (AGB) interact in Amazonian agroforestry systems (AFS) is essential for designing land-use strategies that support climate mitigation and ecosystem resilience. We conducted a meta-analysis to quantify the co-benefits of woody species diversity and aboveground biomass stocks along a climatic gradient across Amazon agroforestry systems. We integrated updated field data from Amazonian AFS and applied a machine-learning clustering approach to identify a natural threshold in woody species richness, allowing us to objectively separate systems into simple (low-diversity) and complex (high-diversity) groups. Complex AFS exhibited higher aboveground biomass, with a median of 55.05 Mg ha−1, while simple AFS showed 36.21 Mg ha−1. Using generalized linear mixed models, we found that species richness and AGB are positively interdependent, indicating strong biodiversity–biomass co-benefits across AFS. Among climatic predictors, mean diurnal temperature range (MDR) emerged as the primary factor negatively influencing species richness, whereas other climatic variables, including mean annual temperature, potential evapotranspiration, and climatic water deficit, showed no significant effects. These results highlight that daily thermal variability, rather than broad-scale climatic gradients, plays a key role in shaping biodiversity within managed Amazonian landscapes. Although AFS can buffer some environmental stress through canopy structure and soil–vegetation interactions, high MDR remains a critical climatic constraint for biodiversity. Overall, our findings emphasize the intertwined roles of biotic and climatic drivers in Amazonian AFS and reinforce their potential to simultaneously conserve biodiversity and enhance carbon storage under increasing climate variability.