The Primary Drivers of Greenhouse Gas Emissions Along the Water Table Gradient in the Zoige Alpine Peatland

Abstract

Zoige alpine peatland as the highest and largest peat swamp area in the world plays an important role in regulating global climate change and stabilizing GHG emissions, and GHG emissions are getting more and more concern due to water table decline induced by the combined effects of climate warming and digging ditches in Zoige alpine peatland. Therefore, emissions of CH4, CO2, and N2O were investigated in situ along different water table transects in Zoige peatland. Results showed that the CO2 and N2O fluxes increased along the reduced water table gradient except the lowest water table sites, while CH4 flux was decreased. Meanwhile, the global warming potential decreased from 798.6 to 430.9 g CO2 eq m− 2 h− 1 with the declined water table. Stepwise multiple regression analysis demonstrated that SOC was the primary factor explaining the variations of CO2 and N2O fluxes across different water table levels, and soil water content was the most important factor to explain the CH4 flux. Water table was the primary driver to determine the GHG fluxes, and the CO2 and N2O emissions were also dependent on the SOC variations. Overall, our results would be beneficial to understand the mechanism of water table effect on GHG emission in alpine peatland ecosystem and provide supports for alpine peatland management in the future.