The Influence of Vegetation and Snow Cover on Soil Greenhouse Gas Fluxes in the Permafrost Region of Northeast China

Permafrost is an important carbon pool for terrestrial ecosystems and a significant source of atmospheric greenhouse gases, but the effects of ground vegetation and snow cover on permafrost greenhouse gas fluxes are still unclear. The soil–atmosphere exchange fluxes of greenhouse gases (mainly carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) occupy key roles during the winter snow and the vegetation growing seasons. Here, a typical Larix gmelinii forest, located in the permafrost region of the Daxing’an Mountains, northeast China, was studied. Using the static chamber-gas chromatograph method, the relationship between soil greenhouse gas emissions, ground vegetation, and snow cover was investigated. We found that the CO2, CH4, and N2O cumulative fluxes from vegetative soils had increased by 19.5%, 37.5%, and 10.7%, compared with fluxes from areas where the ground vegetation had been removed. Snow cover increased soil CO2 cumulative flux by 53.1% and soil N2O cumulative flux by 28.6%, and soil CH4 cumulative flux decreased by 39.3%. Our results show that snow cover and ground vegetation removal reduce CO2 and N2O emissions from permafrost soils. Ground vegetation removal also increases the absorption of CH4 in permafrost soils, while snow cover removal promotes CH4 emissions. These findings confirm the effects of ground vegetation and snow cover on the transformation processes of greenhouse gases from forest ecosystems in permafrost regions. Therefore, this research provides scientific data support for the improvement of land surface climate models and the mitigation of climate change in cold regions.