Ecosystem dynamics in boreal cutover peatlands restored and reused for photovoltaic production

In Finland there are tens of thousands of hectares of drained peat extraction sites (‘cutover peatlands’) in which the extraction has recently ceased, leaving an amount of peat still on site. Restoration and productive reuse of such cutover peatlands and related research on their impact have been ongoing for studying and mitigating greenhouse gas (GHG) emissions, sustaining wetland ecosystem services, and developing local economy. Such comprehensive restoration and paludicultural reuse often include rewetting, vegetation restoration (with fertilisation if necessary), solar or wind power production, and/or agricultural (including husbandry) use provided that the vegetation regenerates sufficiently. In the current EU-funded project ‘AurinkoSuo’, we use modelling tools to investigate the dynamics of carbon dioxide and methane emissions, vegetation regeneration, peat carbon pools, and net ecosystem production (NEP) during peat extraction, vegetation restoration, and reuse for photovoltaic production in cutover peatlands in southwestern Finland. We modified land surface model JSBACH for cutover peatlands, coupled it with peatland GHG model HIMMELI, and used the coupled model to simulate the aforementioned dynamics over 1996—2055. The model was parameterized using specific literature on cutover peatlands and information on our study sites, and the climate forcing inputs were obtained from the Coupled Model Intercomparison Project Phase 6 (CMIP6) in the scenario of Shared Socioeconomic Pathway (SSP) 1-2.6. The panels’ shading effects on the ground vegetation were modelled and implemented into our simulation. The simulation included different combinations of water table depths, shading effects, and biomass removal (mimicking crop harvesting or husbandry use). Our work is among the first attempts to model the GHG- and vegetation-related processes in WPG paludiculture spanning over the historical peat extraction to the future with changing climate.