From forest to open bog : A status report from a forest-to-open bog-restoration, 8 years later

Peatlands are associated with a range of ecosystem services such as long-term carbon storage and sequestration, biodiversity, and potential water reservoirs, mitigating floods and droughts. However, in the 20th century, large peatland areas in the northern temperate and boreal regions were drained by ditching, primarily to enhance forest and agricultural production and peat harvesting. Drainage of peatland is associated with a reduction in wet tolerant peatland species, reduced long term carbon sequestration and increased carbon emissions, conflicting with the goals of the Convention on Biological Diversity (CBD) and the Paris Agreement. Today, there is a big ongoing effort from society to rewet and restore drained peatlands in Sweden, but post- restoration monitoring to evaluate success are often scarce. Here, I examine the recovery of a restored drained and afforested bog in Southern Sweden, using a pristine area of the bog as the reference target. The aim was to ascertain to what extend the restoration had succeed and its potential to fully recover. During one year pore water quality, water level and peat surface level were monitored. In the fall peat cores were collected to investigate differences in peat physical and elemental and the microbial biomass and composition. I found that there are still considerable differences between restored and reference area, most marked by the deeper water level in the restored area, but this was not due to a reduced capacity of peat oscillation (i.e. the peats ability to expand and shrink to follow the water table. However, the restoration had raised the water table closer to the surface when compared to other drained areas in Sweden. The study also found considerable higher quantities and higher aromaticity of dissolved organic matter (e.g. DOC) in the porewater of the restored area and an overall lower total amount of microbial biomass with altered community composition, with higher relative amounts’ of fungi and G- negative bacteria’s in the restored area. The nutrient profile in the porewater (inorganic N,P,K) were similar to what was found in the reference area. In conclusion, both the hydrological and porewater chemistry status are currently most likely sufficient for wet-dwelling peat mosses to establish. Here, I argue that the restoration effect is noticeable but complete recovery is yet far away and there is a risk of recession towards afforestation if peat mosses fails to re-establish