Gao Wen-Qiang, Lei Xiang-Dong, Gao Dong-Li, Li Yu-Tang
Key Laboratory of Forest Management and Growth Modelling State Forestry and Grassland Administration Institute of Forest Resource Information Techniques Chinese Academy of Forestry Beijing China.
Planning and Design Institute of the Forest Products Industry of the State Forestry and Grassland Administration Beijing China.
Ecol Evol. 2021 Nov 12;11(23):16806-16816. doi: 10.1002/ece3.8312. eCollection 2021 Dec.
Forests play a key role in regulating the global carbon cycle, a substantial portion of which is stored in aboveground biomass (AGB). It is well understood that biodiversity can increase the biomass through complementarity and mass-ratio effects, and the contribution of environmental factors and stand structure attributes to AGB was also observed. However, the relative influence of these factors in determining the AGB of forests remains poorly understood. Using a large dataset retrieved from 523 permanent forest inventory plots across Northeast China, we examined the effects of integrated multiple tree species diversity components (i.e., species richness, functional, and phylogenetic diversity), functional traits composition, environmental factors (climate and soil), stand age, and structure attributes (stand density, tree size diversity) on AGB based on structural equation models. We found that species richness and phylogenetic diversity both were not correlated with AGB. However, functional diversity positively affected AGB via an indirect effect in line with the complementarity effect. Moreover, the community-weighted mean of specific leaf area and height increased AGB directly and indirectly, respectively; demonstrating the mass-ratio effect. Furthermore, stand age, density, and tree size diversity were more important modulators of AGB than biodiversity. Our study highlights that biodiversity-AGB interaction is dependent on the regulation of stand structure that can be even more important for maintaining high biomass than biodiversity in temperate forests.
森林在调节全球碳循环中起着关键作用，其中很大一部分碳储存在地上生物量（AGB）中。人们很清楚，生物多样性可以通过互补效应和质量比效应增加生物量，并且也观察到了环境因素和林分结构属性对地上生物量的贡献。然而，这些因素在决定森林地上生物量方面的相对影响仍然知之甚少。利用从中国东北523个森林资源连续清查样地中获取的大型数据集，我们基于结构方程模型研究了多种树木物种多样性组成部分（即物种丰富度、功能多样性和系统发育多样性）、功能性状组成、环境因素（气候和土壤）、林分年龄和结构属性（林分密度、树木大小多样性）对地上生物量的影响。我们发现物种丰富度和系统发育多样性均与地上生物量不相关。然而，功能多样性通过与互补效应一致的间接效应正向影响地上生物量。此外，比叶面积和树高的群落加权均值分别直接和间接增加了地上生物量；这体现了质量比效应。此外，林分年龄、密度和树木大小多样性对地上生物量的调节作用比生物多样性更为重要。我们的研究强调，生物多样性与地上生物量的相互作用取决于林分结构的调节，在温带森林中，林分结构对维持高生物量可能比生物多样性更为重要。
