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Despite covering only 3 % of the planet's land surface, peatlands store 30 % of the planet's terrestrial carbon. The net greenhouse gas (GHG) emissions from peatlands depend on many factors but primarily soil temperature, vegetation composition, water level and drainage, and land management. However, many peatland models rely on water levels to estimate CH 4 exchange, neglecting to consider the role of CH 4 transported to the atmosphere by vegetation. To assess the impact of vegetation on the GHG fluxes of peatlands, we have developed a new model, Peatland-VU-NUCOM (PVN). The PVN model is a site-specific peatland CH 4 and CO 2 emissions model, able to reproduce vegetation dynamics. To represent dynamic vegetation, we have introduced plant functional types and competition, adapted from the NUCOM-BOG model, into the framework of the Peatland-VU model, a peatland GHG emissions model. The new PVN model includes plant competition, CH 4 diffusion, ebullition, root, shoot, litter, exudate production, belowground decomposition, and aboveground moss development under changing water levels and climatic conditions. Here, we present the PVN model structure and explore the model's sensitivity to environmental input data and the introduction of the new vegetation competition schemes. We evaluate the model against observed chamber data collected at two peatland sites in the Netherlands to show that the model is able to reproduce realistic plant biomass fractions and daily CH 4 and CO 2 fluxes. We find that daily air temperature, water level, harvest frequency and height, and vegetation composition drive CH 4 and CO 2 emissions. We find that this process-based model is suitable to be used to simulate peatland vegetation dynamics and CH 4 and CO 2 emissions. [ABSTRACT FROM AUTHOR]

Despite covering only 3% of the planet's land surface, peatlands store 30% of the planet's terrestrial carbon. The potential to both emit and drawdown CO2 and CH4, means that peatlands have a complex and multifaceted relationship with the global climate system. The net GHG emissions from peatlands depends on many factors but primarily vegetation composition, ground water level and drainage, land management, and soil temperature. Many peatland models use surface water levels to estimate CH4 exchange, neglecting to consider the efficiency of CH4 transported to the atmosphere by vegetation. To assess the impact of vegetation on the GHG fluxes of peatlands, we have developed a new model, Peatland-VU-NUCOM PVN). The new PVN model has been built from two parent models, the Peatland-VU and NUCOM-BOG models. To represent dynamic vegetation, we have introduced plant functional types and competition, adapted from the NUCOM-BOG model, into the Peatland-VU model. The PVN model includes plant competition, CH4 diffusion, ebullition, root, shoot, litter, exudate production, below-ground decomposition, and above-ground moss development, under changing water levels and climatic conditions. PVN is a site-specific peatland CH4 and CO2 emissions model, able to reproduce vegetation dynamics. Here, we present the PVN model structure and explore the model's sensitivity to environmental input data and the introduction of the new vegetation-competition schemes. We evaluate the model against observed chamber data collected at two peatland sites in the Netherlands to show that the model is able to reproduce realistic plant biomass fractions, and daily CH4 and CO2 fluxes. We find that this plot-scale model is flexible and robust and suitable to be used to simulate vegetation dynamics and emissions of other peatland sites. [ABSTRACT FROM AUTHOR]

Peatlands are the world's largest terrestrial carbon store. Despite covering only 3% of the planet's land surface, peatlands store 30% of the planet's terrestrially available carbon. The Dutch government's 2019 National Climate Agreement committed to reduce the contribution of peatlands to total national Dutch GHG emissions, by 1 MtonCO2 per year (or 20%) until 2030. Countries with similarly degraded peatlands are likely to face similar commitments in the coming years. Restoration (or rewetting) is a proposed solution to reduce land subsidence and increase carbon sequestration in agricultural peatlands but is often accompanied by large CH4 emissions. Whilst, previous studies have investigated whether singular plant types impact the greenhouse gas (GHG) emissions of peatlands, few (or no) studies have investigated the impact of plant composition on GHG emissions in peatlands. To assess the impact of dynamic vegetation on subsequent GHG fluxes in peatlands, we developed a new model, Peatland-VU-NUCOM (PVN). This is the second process-based model to date, capable of simulating dynamic vegetation, CO2, and CH4 emissions in peatlands. The new PVN model simulates CH4 and CO2 fluxes in relation to the plant community composition. The PVN model includes plant competition, CH4 diffusion, ebullition, root, shoot, litter exudate production, belowground decomposition, and aboveground moss development, under changing water table and climatic conditions. The model was compared against obser15 vational data collected at two sites in the Netherlands. These results showed that plant communities impact net GHG emissions. This is the first time that a peatland emissions model is able to investigate the role of re-introducing peat forming vegetation on subsequent GHG emissions. We also found that the initial plant community influenced the potential for harvest events to reduce GHG emissions. These results indicated that plant community restoration is a critical component of peatland restoration. [ABSTRACT FROM AUTHOR]