[A-CG39] Biogeochemical cycles in Land Ecosystem

[ACG39-02] Carbon dioxide balance of tropical peat swamp forests in Central Kalimantan, Indonesia

*Takashi Hirano¹, Shinjiro Ohkubo¹, Masayuki Itoh², Hayato Tsuzuki³, Ayaka Sakabe⁴, Hidenori Takahashi⁵, Kitso Kusin⁶, Mitsuru Osaki¹ (1.Hokkaido University, 2.University of Hyogo, 3.Ehime University, 4.Kyoto University, 5.Hokkaido Institute of Hydro-climate, 6.University of Palangkaraya)

Keywords:eddy covariance technique, drainage, fire, drought, ENSO

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 Peninsula. This 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 during the last two decades. Such human disturbances change its carbon dioxide (CO₂). Drainage potentially increases CO₂ emissions through enhanced oxidative peat decomposition because of groundwater level lowering. Thus, it is essential to assess the CO₂ balances of PSFs in different disturbance conditions to understand the role of PSF in the regional and global environments. We had continuously measured eddy CO₂ and energy fluxes above three peat ecosystems of a little drained PSF, a drained PSF, and a degraded PSF by burning and drainage in Central Kalimantan, Indonesia for more than 12 years. Based on the long-term monitoring data, I’ll talk about the effects of human and natural disturbances due to drainage, burning, and ENSO drought.