Taxonomic Diversity Predicts Aboveground Biomass Mainly Through Functional Dominance Across Subtropical Forest Succession

Understanding how taxonomic diversity influences forest aboveground biomass is crucial for sustaining ecosystem services and functioning, especially in the context of global biodiversity loss. Although manipulative experiments have shown that both functional diversity and functional dominance contribute to biomass production, with functional diversity gaining importance over time, their relative roles during natural forest succession remain less understood.

To address this knowledge gap, a research team led by Professor YE Qing at the South China Botanical Garden, Chinese Academy of Sciences, together with Dr. GU Chunfeng, Dr. LIU Hui, and Dr. YIN Deyi, in collaboration with Professor Marc W. Cadotte from the University of Toronto, conducted a study at the Dinghushan National Nature Reserve. Using tree growth data collected from 2010 to 2020 across three forests representing early, middle, and late successional stages, the team investigated whether and how taxonomic diversity influences tree aboveground biomass through community functional traits, focusing on five key functional attributes: leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, wood density, and tree height.

The findings reveal that during subtropical forest succession, taxonomic diversity primarily influences tree aboveground biomass indirectly through its impact on functional properties rather than directly. Across all successional stages, functional dominance consistently emerged as the stronger predictor of biomass compared to functional diversity. In the early and middle stages, the dominance of species with fast leaf economic traits directly and negatively impacted biomass accumulation. By contrast, in the late stage, the dominance of tall species directly promoted greater biomass. Although functional diversity contributed increasingly to biomass accumulation over succession, its effects were mainly indirect, mediated by its influence on functional dominance.

This study highlights that functional dominance, which represents the biomass ratio hypothesis, is the primary mechanism linking taxonomic diversity to aboveground biomass production during forest succession. The findings enhance this understanding of the mechanisms that maintain ecosystem functioning and provide important guidance for forest restoration and management practices. In particular, they emphasize the need to prioritize the selection and management of species possessing key functional traits to optimize ecosystem productivity and resilience under global environmental change.

The study, titled "Taxonomic diversity predicts aboveground biomass mainly through functional dominance across subtropical forest succession," has been published in the Journal of Plant Ecology. This work was financially supported by the National Natural Science Foundation of China and the South China Botanical Garden, Chinese Academy of Sciences. Paper link: https://doi.org/10.1093/jpe/rtaf038

Fig. 1. Standardized estimated coefficients and 95% confidence intervals for predictors from mixed-effects models analyzing the relationships between tree aboveground biomass and combined predictors in the early, middle and late successional stages are presented in (a)-(c). The stacked bars show the relative importance of each predictor group. Significance levels are noted as *P < 0.05; **P < 0.01; ***P < 0.001.（Imaged by GU et al）