Identifying environmental drivers of greenhouse gas emissions under warming and reduced rainfall in boreal-temperate forests

1.Atmospheric concentrations of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are predicted to increase as a consequence of fossil fuel emissions and the impact on biosphere-atmosphere interactions. Forest ecosystems in general, and forest soils in particular, can be sinks or sources for CO2, CH4, and N2O. Environmental studies traditionally target soil temperature and moisture as the main predictors of soil greenhouse gas (GHG) flux from different ecosystems; however, these emissions are primarily biologically driven. Thus, little is known about the degree of regulation by soil biotic vs. abiotic factors on GHG emissions, particularly under predicted increase in global temperatures, and changes in intensity and frequency of precipitation events.

2.Here we measured net CO2, CH4 and N2O fluxes after 5 years of experimental warming (+3.4°C), and 2 years of ≈45% summer rainfall reduction, in two forest sites in a boreal-temperate ecotone under different habitat conditions ...

1. 大气中二氧化碳（CO₂）、甲烷（CH₄）与一氧化二氮（N₂O）的浓度预计将因化石燃料排放，以及生物圈与大气间的相互作用受扰动而升高。总体而言，森林生态系统（尤其是森林土壤）可作为CO₂、CH₄及N₂O的汇或源。传统环境研究通常将土壤温度与湿度作为不同生态系统土壤温室气体（Greenhouse Gas, GHG）通量的核心预测因子，但此类排放本质上主要由生物过程驱动。因此，目前对土壤生物与非生物因子对温室气体排放的调控程度尚知之甚少，尤其是在全球气温预计升高、降水事件的强度与频率发生变化的背景下。
2. 本研究在寒温带交错带的两个生境条件各异的森林样地中，开展了为期5年的模拟增温（+3.4℃）试验与为期2年的夏季降水削减约45%的控制试验，并测定了各样地的净CO₂、CH₄与N₂O通量……