Bryophytes impact the fluxes of soil non-carbon dioxide greenhouse gases in a subalpine coniferous forest

Abstract

Terrestrial bryophytes substantially regulate ecosystem processes in high latitude and high elevation ecosystems; however, the role of these plants in mediating soil emissions of non-CO 2 greenhouse gases (GHGs) (N 2 O and CH 4 ) in these ecosystems remains poorly understood. A removal experiment was conducted to investigate the influence of bryophytes on soil non-CO 2 GHGs emission in a subalpine coniferous forest on the eastern edge of the Tibetan Plateau. Bryophyte removal decreased the average N 2 O emission rate, but did not significantly alter the CH 4 flux rate. The cumulative amount of N 2 O emission and CH 4 uptake was decreased by bryophyte removal. Compared to bryophyte-removal plots, soil in the control plots had higher concentrations of soil organic C (SOC), total N (TN), dissolved organic C (DOC), dissolved N (DN), and exchangeable NH 4 + . The control plots also had higher cumulative N 2 O emission and CH 4 uptake compared to plots with bryophytes removed. Bryophyteremoval significantly changed the relationship between soil non-CO 2 GHGs flux rates and soil water content, induced a linear decreasing relationship between the N 2 O emission rate and soil water content and a quadratic relationship between CH 4 flux rate and soil water content in the bryophyte-removal plots. Results from this study indicate that bryophytes may regulate non-GHG emissions from subalpine coniferous soils and demonstrate that in the presence of bryophytes, these soils may act as a greater N 2 O source and CH 4 sink in southwestern China.