From peat swamp forest to oil palm plantations: The stability of tropical peatland carbon
From peat swamp forest to oil palm plantations: The stability of tropical peatland carbon
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DOI：
10.1016/j.geoderma.2019.02.021
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发表时间：
2019-05-15
期刊：
影响因子：
6.1
通讯作者：
Sjogersten, Sofie
中科院分区：
文献类型：
--
作者：
Cooper, Hannah V.;Vane, Christopher H.;Sjogersten, Sofie
准确评估热带泥炭地碳动态对于以下方面很重要：(A)确定活性碳池的规模；(B)估计土地利用变化导致的泥炭温室气体向大气转移的规模；以及(C)支持碳减排政策。迄今为止，关于热带泥炭地有机质的质量及其对全球气温上升的敏感性的信息有限，特别是在土地转用的背景下。因此，这项工作的目的是确定泥炭质量和潜在温室气体排放在热带泥炭地淹没条件下的温度响应。同时反映了从森林到油棕榈种植园的转变过程。选择了代表泥炭沼泽林向油棕榈林转变阶段的四种土地利用类型：(I)次生‘森林’，(Ii)最近‘排水’但未清理的森林(Iii)清理和最近种植的‘幼龄油棕榈林’和(Iv)‘成熟油棕榈林’人工林。总体而言，表层泥炭碳比深层泥炭更不稳定。最大的不稳定水池是在森林地点测量的。在退耕后期，活性碳流失，顽固性有机物相对丰度增加。与深层泥炭相比，表层泥炭中潜在的温室气体通量最大，随着土地转换后活性碳的耗尽，潜在的温室气体通量下降。在转化的所有阶段，温度升高导致潜在温室气体排放量增加，但温度响应的大小取决于有机质的稳定性。对于CO2通量，林地的温度响应最为明显。这反映了这种土地利用的更大的泥炭不稳定性。相比之下，在CH4排放方面，温度较高的森林和耕地类型的排放量都有所增加。这表明，随着气候变暖而升高的温度可能会导致以降解有机物为主的地点产生更高的CH4排放。总而言之，这项研究表明，在从泥炭沼泽林向油棕榈林转变的过程中，腐解率的增强和凋落物投入的减少最终反映在泥炭潜在的总二氧化碳排放量的减少上。尽管如此，气候变暖导致的较高温度可能会使种植园地点的温室气体排放量居高不下。
Accurate assessment of tropical peatland carbon dynamics is important to (a) determine the size of the active carbon pool, (b) estimate the scale of transfers of peat-derived greenhouse gases (GHGs) to the atmosphere resulting from land use change, and (c) support carbon emissions reduction policies. To date, information on the quality of tropical peatland organic matter and its sensitivity to increases in global temperatures is limited, particularly in the context of land conversion. The aim of this work is therefore to determine peat quality and temperature response of potential GHG emissions under flooded conditions from tropical peatland sites. Whilst reflecting the process of conversion from forest to oil palm plantation. Four land use types that represent the stages of conversion from peat swamp forest to oil palm were chosen: (i) secondary 'forest', (ii) recently 'drained' but not cleared forest (iii) cleared and recently planted 'young oil palm' plantation and (iv) 'mature oil palm' plantation. Overall, surface peat carbon was more labile than deeper peats. The largest labile pool was measured at forest sites. In the later stages of land conversion, the labile carbon had been lost and the relative abundance of recalcitrant organic material increased. Potential GHG fluxes were greatest in surface peas compared to deeper peats and declined as labile carbon was depleted following land conversion. Higher temperatures resulted in higher potential GHG emissions at all stages of conversion, but the magnitude of the temperature response depended on organic matter lability. For CO2 fluxes, the temperature response was most pronounced at forest sites. This reflects the greater peat lability at this land use. In contrast, for CH4 emissions, there were increased emissions both at forest and converted land types with higher temperatures. This suggests that increasing temperatures in response to climate warming may drive higher CH4 emissions from sites dominated by degraded organic matter. Collectively, this study demonstrates that during conversion from peat swamp forest to oil palm plantation, the enhanced decomposition and reduced litter input rates is reflected eventually in reduced potential gross CO2 emissions from peat. Nonetheless higher temperature resulting from climate warming may maintain high GHG emissions at plantation sites.