Spatial variability of forest floor carbon flux in drained peatlands

Sammanfattning

Peatlands are important ecosystems for carbon storage and sequestration. Currently, these ecosystems are at risk because of climate change and anthropogenic activities such as drainage, which can shift them from being a carbon sink to a source. Understanding variation in carbon fluxes in peatlands is essential to predict whether they will continue as a carbon sink or act as a source. In this study, my aim was to quantify and understand the spatial variation of forest floor carbon flux (CO₂ and CH₄) in drained peatlands. I used chamber measurements in dark and light conditions across 10 different sites in southern Sweden. In total, 900 locations were sampled at one time point, and at each location I measured abiotic factors such as temperature, light and moisture, and biotic factors like percentage cover of sedges, dwarf shrubs, mosses, and Sphagnum, I identified how different environmental and vegetation factors influence instant carbon flux in these ecosystems. My results show that all the fluxes (NEE, ER, GPP and CH₄) have higher variability within sites than across sites. Also, CO₂ flux is mainly driven by temperature and vascular plants, while CH₄ flux varies depending on soil moisture and vegetation composition. Sphagnum and sedges were associated with higher CH₄ emissions, while the cover of non-Sphagnum moss had the opposite effect. In conclusion, this study highlights the strong spatial variability of carbon fluxes in drained peatlands and improves our understanding of carbon dynamics in these ecosystems by emphasizing on the role of temperature, soil moisture, and vegetation composition in CO₂ and CH₄ flux.