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：土壤提供关键生态系统服务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。当前主流的土壤功能分类体系多以植被为核心，例如植物功能型（Plant Functional Types, PFTs），却忽略了土壤自身的特征与过程。本研究提出土壤功能型（Soil Functional Types, SFTs）这一概念性框架，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：本研究依托某林区内CO₂、CH₄及N₂O土壤通量的自动监测数据，将具有相似温室气体动态特征的地表单元定义为土壤功能型。研究采用混合效应模型，对环境变量与土壤功能型分类结果分别开展独立聚类分析。研究结果：基于土壤功能型得到的独特聚类分组（而非基于环境变量的分组）验证了本研究假说：相较于常规测定的土壤参数（如土壤含水量、土壤温度、枯落物生物量）所承载的信息，土壤功能型可额外揭示土壤功能的空间变异特征。研究结论：该方法可作为基于植被的功能分类体系的补充，以更全面地表征多样的生态系统功能。本研究提出的土壤功能型框架若要实现全球应用，需依托学界共同体携手共享数据，构建全球土壤温室气体排放数据库。