Carbon balance of tropical peat ecosystems in Borneo

Tropical peat swamp forest (PSF) is a unique ecosystem rich in carbon and water, which is widely distributed in Southeast Asia’s coastal lowlands, mainly in Borneo, Sumatra and Malay Peninsular. The ecosystem has accumulated a huge amount of organic carbon in peat soil over millennia under the condition of high groundwater level. However, PSF has been reduced and degraded by logging, drainage and burning mainly because of land conversion to oil palm and pulp wood plantations during the last two decades. Such human disturbances potentially increase carbon dioxide (CO₂) emissions to the atmosphere through enhanced oxidative peat decomposition and the increased risk of peat fires. Thus, it is essentail to assess the current carbon status of tropical peatlands and quantify the effects of disturbance on the carbon balance to understand the role of tropical peatlands in the regional and global carbon balances. We have continuously measured ecosystem-scale eddy fluxes and soil fluxes of CO₂ and methane (CH₄) in different tropical peat ecosystems, including a little drained PSF, a drained PSF, a burned ex-PSF and an oil palm plantation, in Central Kalimantan, Indonesia, and Sarawak, Malaysia, in Borneo. Based on the monitoring data, I’ll talk about the carbon balance of tropical peat ecosystems, such as its seasonal variation and its relationship with groundwwater level, and the effect of disturbance due to human activities and ENSO drought on the carbon flux and balance.