Decade of natural regeneration increases carbon accumulation in a drained peatland pasture

Abstract

Drained peatlands represent significant carbon sources, having emitted ∼80 petagrams (Pg) of carbon dioxide. Natural regeneration of these peatlands holds potential to enhance carbon uptake and mitigate climate change; however, this potential has not been adequately incorporated into global carbon budgets. Here, we investigated the carbon accumulation rates and chemical composition in a natural bog and an adjacent drained peatland pasture undergoing decades of regeneration. In addition, we conducted a meta-analysis to investigate long-term changes in carbon sink function of drained peatlands utilized for peat extraction, agriculture, forestry, and grassland. Compared to the natural bog, decades of regeneration significantly increased carbon accumulation to 231 g C m⁻² yr⁻¹, attributable to elevated plant biomass and carbon uptake. However, this increase was confined to the top 30 cm depth. Regeneration did not affect deep carbon storage but altered carbon composition, shifting from recalcitrant carbon (alkyl) to labile carbon (O-alkyl). Globally, drained peatlands under various land uses have been shown to enhance their carbon sink capacity. However, after approximately 100 years following land use change, the strength of this increased carbon sink function showed a declining trend. These findings underscore that drained peatlands with regenerative potential can ultimately reach a new stable state conducive to carbon accumulation, considering their high initial carbon accumulation rates and the cessation of human interference. This study highlights the critical role of drained peatlands play in climate change mitigation, emphasizing the need to integrate this potential into global carbon budgets and carbon models.