Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.
Sci Total Environ. 2021 Aug 20;783:146968. doi: 10.1016/j.scitotenv.2021.146968. Epub 2021 Apr 14.
The interactions between plants and soils lead to complex feedbacks that regulate intrinsic water use efficiency (iWUE) and stomatal conductance (gs) at ecosystem level and reflect water constraints on plant productivity. However, the relationships among soil properties, biodiversity, and leaf functional traits contributing to the variability in ecosystem iWUE and gs remain largely unknown. To elucidate these relationships, we used principal component analysis to reduce soil properties to a fertility spectrum and a limiting-resource spectrum across grassland, and early-, mid- and late-successional forests in a karst catchment. Leaf functional traits at community level were calculated based on leaf biomass, and were reduced to an economic spectrum and a limiting-resource spectrum. Leaf carbon (δC) and oxygen (δO) stable isotopes at community levels were used as proxies for ecosystem iWUE and g. The effects of soil properties, biodiversity (taxonomic, functional and phylogenetic diversity) and leaf traits on δC and δO were evaluated using structural equation models. Our results showed that variability in ecosystem iWUE and gs was determined overwhelmingly by indirect effects of soil properties via two different pathways: the soil fertility spectrum, determining the number of coexisting species (taxonomic diversity) and turnover of species (leaf economic spectrum), and the soil limiting-resource spectrum, shaping the specific phylogenetic lineages (phylogenic diversity). In addition, δC and δO were constrained by the interactive effects of leaf economic spectrum, and taxonomic and phylogenic diversity; total effects of biodiversity on δC and δO were larger than those of leaf economic spectrum. Our study highlighted the critical role of the evaluating interaction relationships between leaf functional traits, biodiversity metrics and soil properties in understanding the mechanisms of ecosystem function responding to environmental change.
植物和土壤之间的相互作用导致了复杂的反馈，调节了生态系统水平的内在水分利用效率(iWUE)和气孔导度(gs)，反映了水对植物生产力的限制。然而，土壤特性、生物多样性和叶片功能性状之间的关系，这些因素有助于解释生态系统 iWUE 和 gs 的变异性，在很大程度上仍然未知。为了阐明这些关系，我们使用主成分分析将土壤特性简化为肥力谱和限制资源谱，横跨喀斯特流域的草原、早期、中期和晚期演替森林。根据叶片生物量计算群落水平的叶片功能性状，并将其简化为经济谱和限制资源谱。群落水平的叶片碳(δC)和氧(δO)稳定同位素被用作生态系统 iWUE 和 g 的替代物。使用结构方程模型评估土壤特性、生物多样性(分类学、功能和系统发育多样性)和叶片性状对δC 和δO 的影响。我们的结果表明，生态系统 iWUE 和 gs 的变异性主要是由土壤特性通过两条不同途径的间接效应决定的:土壤肥力谱，决定共存物种的数量(分类多样性)和物种的周转率(叶片经济谱)，以及土壤限制资源谱，塑造特定的系统发育谱系(系统发育多样性)。此外，δC 和δO 受到叶片经济谱、分类和系统发育多样性的相互作用的限制;生物多样性对δC 和δO 的总效应大于叶片经济谱的总效应。我们的研究强调了评估叶片功能性状、生物多样性指标和土壤特性之间相互作用关系在理解生态系统功能对环境变化响应机制中的关键作用。
