Data from: Using greenhouse gas fluxes to define soil functional types

Aim: Soils provide key ecosystem services and directly control ecosystem functions; thus, there is a need to define the reference state of soil functionality. Most common functional classifications are vegetation-centered, such as plant functional types (PFTs), and neglect soil characteristics and processes. We propose Soil Functional Types (SFTs) as a conceptual approach to represent and describe the functionality of soils based on characteristics of their greenhouse gas (GHG) flux dynamics. Methods: We used automated measurements of CO2, CH4 and N2O soil fluxes in a forested area to define SFTs as surface areas with similar GHG dynamics. We performed mixed effects models, and independent cluster analyses of our environmental variables and SFT classifications. Results Unique groupings based on SFTs, but not environmental variables, supported the hypothesis that SFTs provide additional insights on the spatial variability of soil functionality beyond information represented by commonly measured soil parameters (e.g., soil moisture, soil temperature, litter biomass). Conclusions: This approach could complement vegetation-based functional classifications to better represent the broad range of ecosystem functions. A global application of the proposed SFT framework will only be possible if there is a community-wide effort to share data and create a global database of GHG emissions from soils.研究目标：土壤是关键生态系统服务的提供者，并直接调控生态系统功能，因此亟需明确土壤功能的参考状态。当前主流的功能分类多以植被为中心，例如植物功能型（Plant Functional Types，PFTs），却忽略了土壤自身的特性与过程。本研究提出土壤功能型（Soil Functional Types，SFTs）这一概念性方法，旨在基于土壤温室气体（Greenhouse Gas，GHG）通量动态特征，表征并描述土壤的功能属性。 研究方法：本研究通过对某林区内土壤CO₂、CH₄及N₂O通量的自动化监测数据，将具有相似温室气体动态特征的地表区域定义为土壤功能型。我们采用混合效应模型，并对环境变量与土壤功能型分类结果开展独立聚类分析。 研究结果：基于土壤功能型得到的独特聚类分组（而非仅基于环境变量）验证了相关假说：相较于常规测定的土壤参数（如土壤湿度、土壤温度、枯落物生物量）所承载的信息，土壤功能型能够进一步揭示土壤功能的空间异质性。 研究结论：该方法可补充基于植被的功能分类体系，从而更全面地表征生态系统功能的多样性。若要在全球范围内推广本研究提出的土壤功能型框架，需全球科研共同体携手共享数据，构建全球性的土壤温室气体排放数据库。