Blanket bog CO2flux driven by plant functional type during summer drought

Recent climate predictions for the United Kingdom expect a nation-wide shift towards drier and warmer summers, increasing the risk of more frequent and severe drought events. Such shifts in weather patterns impede functioning of global peatlands, especially rare intact blanket bogs abundant in Scotland and representing nearly a quarter of the UK’s soil carbon. In this in situ studycarbon dioxide (CO2) fluxes from dominant peatland plant functional types(PFTs) such as Sphagnumspp., graminoids, ericoids,and other key covertypes (i.e., pools and bare peat) were measured and compared across upland and low-lying blanket bog margins and centres, immediately before and during a summer drought in 2018, and over the subsequent year. During that period, most sites acted as net sources of CO2to the atmosphere. Our results showedthat Net Ecosystem Exchange (NEE) was limited by water availabilityduring the drought, with ericoid shrubs showing the highest drought resilience, followed by graminoids This article is protected by copyright. All rights reserved.(which were stilllimited in GPP in 2019) and Sphagnummosses.Diverging NEE estimates were observed across centre and margin areas of the blanket bogs, with highest variability across the upland site where signs of active erosion were visible. Overall, this our study suggests that estimating growing season carbon fluxes from in situpeatland PFT and cover types can help us better understand global climate change impacts on the dynamics and trajectories of peatland C cycles.