Response of CH4 emissions to moss removal and N addition in boreal peatland of northeast China
Abstract. Boreal peatlands are an important natural source of atmospheric methane (CH4). Recently, boreal peatlands have been experiencing increased nitrogen (N) availability and decreased moss production. However, little is known about the interactive effect of moss and N availability on CH4 emissions in boreal peatlands. In this study, the effects of moss removal and N addition (6 g N m−2 yr−1) on CH4 emissions were examined during the growing seasons of 2011, 2012 and 2013 in a boreal peatland in the Great Hinggan Mountain of northeast China. Notably, the response of CH4 emissions to moss removal and N addition varied with experimental duration. Moss removal and N addition did not affect CH4 emissions in 2011 and 2012, but respectively reduced CH4 emissions by 50% and 66% in 2013. However, moss removal and N addition did not produce an interactive effect on CH4 emissions. Consequently, moss removal plus N addition had no effect on CH4 emissions in 2011 and 2012, but decreased CH4 emissions by 68% in 2013. These results suggest that the effects of moss removal and N enrichment on CH4 emissions are time-dependent in boreal peatlands, and also imply that increased N availability and decreased moss growth would independently inhibit CH4 emissions in the boreal peatlands of northeast China.