Carbon Dynamics in Rewetted Tropical Peat Swamp Forests

Taryono Darusman,Impron Impron,Daniel Murdiyarso,Iswandi Anas Chaniago,Dwi Puji Lestari

doi:10.3390/cli10030035

Taryono Darusman, Impron Impron + Show 3 more

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https://doi.org/10.3390/cli10030035

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Abstract

Degraded and drained peat swamp forests (PSFs) are major sources of carbon emissions in the forestry sector. Rewetting interventions aim to reduce carbon loss and to enhance the carbon stock. However, studies of rewetting interventions in tropical PSFs are still limited. This study examined the effect of rewetting interventions on carbon dynamics at a rewetted site and an undrained site. We measured aboveground carbon (AGC), belowground carbon (BGC), litterfall, heterotrophic components of soil respiration (Rh), methane emissions (CH4), and dissolved organic carbon (DOC) concentration at both sites. We found that the total carbon stock at the rewetted site was slightly lower than at the undrained site (1886.73 ± 87.69 and 2106.23 ± 214.33 Mg C ha−1, respectively). The soil organic carbon (SOC) was 1685 ± 61 Mg C ha−1 and 1912 ± 190 Mg C ha−1 at the rewetted and undrained sites, respectively, and the carbon from litterfall was 4.68 ± 0.30 and 3.92 ± 0.34 Mg C ha−1 year−1, respectively. The annual average Rh was 4.06 ± 0.02 Mg C ha−1 year−1 at the rewetted site and was 3.96 ± 0.16 Mg C ha−1 year−1 at the undrained site. In contrast, the annual average CH4 emissions were −0.0015 ± 0.00 Mg C ha−1 year−1 at the rewetted site and 0.056 ± 0.000 Mg C ha−1 year−1 at the undrained site. In the rewetted condition, carbon from litter may become stable over a longer period. Consequently, carbon loss and gain mainly depend on the magnitude of peat decomposition (Rh) and CH4 emissions.

Highlights

Received: 26 January 2022Under global climate warming and drier conditions, many pristine tropical peatland ecosystems have been projected to be carbon sources rather than carbon sinks [1,2]
We encountered dominant tree species from the Anacardiaceace, Dipterocarpaceae, Ebenaceae, Fabaceae, Lauraceae, Myrtaceae, Sapotaceae, and Rutaceae families at the rewetted and undrained sites. These dominant tree species were found at both sites, the rewetted site was dominated by Ebenaceae, while Anacardiaceae dominated the undrained site
Based on the dominant tree composition encountered at both sites, the forest type at the study site could be classified as a mixed swamp forest [53]

Summary

Introduction

Under global climate warming and drier conditions, many pristine tropical peatland ecosystems have been projected to be carbon sources rather than carbon sinks [1,2]. Without immediate forest management interventions, such as peatland rewetting, degraded and drained tropical peat swamp forests (PSFs) will continue to be carbon sources [6]. Unlike the drained PSFs, the field study of carbon dynamics from rewetted PSFs is limited, especially in the tropical climate zone. The availability of primary data from rewetted tropical PSFs is scarce [8–10]. Primary data, such as CO2 emissions from soil respiration (Rs ), CH4 emissions, dissolved organic carbon (DOC), litter productions, soil organic carbon (SOC), and other biophysical properties of peat soil, are needed in order to model the future carbon dynamics under rewetted conditions in tropical PSFs [11].

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