Peatland-VU-NUCOM (PVN 1.0): Using dynamic PFTs to model peatland vegetation, CH ₄ and CO ₂ emissions

Abstract. 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 intro- duction 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.