Climate warming and vegetation composition change are expected to influence greenhouse gas emissions from boreal peatlands. However, the interactive effects of warming and different vegetation compositions on N 2 O dynamics are poorly known, although N 2 O is a very potent greenhouse gas. In this study, manipulated warming and vegetation composition change were conducted in a boreal peatland to investigate the effects on N 2 O fluxes during the growing seasons in 2015 and 2016. We did not find a significant effect of warming treatment and combination treatments of warming and vegetation composition change on N 2 O fluxes. However, sedge removal treatment significantly increased N 2 O emissions by three-fold. Compared with the treatment of shrub and sedge removal, the combined treatment of warming and shrub and sedge removal significantly increased N 2 O consumption by five-fold. Similar to N 2 O fluxes, the cumulative N 2 O flux increased by ~3.5 times under sedge removal treatment, but this effect was not significant. In addition, the results showed that total soil nitrogen was the main control for N 2 O fluxes under combinative treatments of warming and sedge/shrub removal, while soil temperature and dissolved organic carbon were the main controls for N 2 O release under warming combined with the removal of all vascular plants. Our results indicate that boreal peatlands have a negligible effect on N 2 O fluxes in the short-term under climate change, and environmental controls on N 2 O fluxes become increasingly important under the condition of warming and vegetation composition change.
