Rates and spatial variability of peat subsidence in Acacia plantation and forest landscapes in Sumatra, Indonesia
Rates and spatial variability of peat subsidence in Acacia plantation and forest landscapes in Sumatra, Indonesia
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DOI：
10.1016/j.geoderma.2018.12.028
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发表时间：
2019-03-15
期刊：
影响因子：
6.1
通讯作者：
Page, Susan E.
中科院分区：
文献类型：
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作者：
Evans, Chris D.;Williamson, Jennifer M.;Page, Susan E.
欧洲和北美的许多泥炭地已经开发了一个多世纪用于农业，而东南亚的开发主要是自1990年以来进行的。排干的泥炭地的种植现在支持着大量人口的生计，以及印度尼西亚和马来西亚等国正在进行的经济发展。然而，与人工林排水相关的泥炭沉降，与二氧化碳排放增加、对邻近森林栖息地的影响以及人工林排水能力的长期变化有关，既构成了环境挑战，也构成了社会经济挑战。虽然泥炭沉降带来的根本挑战已得到广泛认识，但长期速率和减缓或避免沉降的潜力仍然不确定。我们分析了来自印度尼西亚苏门答腊岛312个地点的2000年沉降测量数据，这些数据来自金合欢纸浆种植园和邻近的原生森林，代表了迄今为止公布的最大的泥炭沉降数据集。金合欢人工林的平均沉降量为每年4.3厘米（-1），并向邻近森林延伸至少300米。平均地下水位（WTD）是人工林和林区沉降速率的最佳预测因子。我们没有发现确凿的证据表明，在相同的排水水平下，金合欢人工林的下沉本质上比原生森林或（与先前的研究相比）油棕人工林更快。我们的研究结果表明，如果能够开发出实际和经济上可行的实现这一目标的方法，将平均wtd提高到印尼政府40厘米的目标可以将目前的种植园下沉率降低25-30%。虽然在任何形式的人工林管理下，泥炭的一定程度的下沉可能是不可避免的，但这些减少-如果大规模实现-将增加人工林的经济寿命，同时减少具有国家和全球意义的二氧化碳排放。
Many peatlands in Europe and North America have been developed for agriculture for over a century, whilst in Southeast Asia development has largely occurred since 1990. Cultivation of drained peatlands now supports the livelihoods of large numbers of people, and the ongoing economic development of countries such as Indonesia and Malaysia. However, peat subsidence linked to plantation drainage represents both an environmental and a socio-economic challenge, associated with elevated CO2 emissions, impacts on adjacent forest habitat, and long-term changes in plantation drainability. Whilst the fundamental challenges presented by peat subsidence are broadly recognised, the long-term rates and the potential for mitigation or avoidance of subsidence remain uncertain. We analysed over 2000 site-years of subsidence measurements from 312 sites in Sumatra, Indonesia, collected under Acacia pulpwood plantation and adjacent native forest, representing the largest peat subsidence dataset published to date. Subsidence averaged 4.3 cm yr(-1) in the Acacia plantations, and extended at least 300 m into adjacent forest. Mean water table depth (WTD) was the best predictor of subsidence rate in both plantation and forest areas. We did not find conclusive evidence that subsidence was intrinsically faster under Acacia plantation than under native forest or (by comparison with previous studies) oil palm plantations for the same level of drainage. Our results suggest that raising average WTDs to the Indonesian Government's 40 cm target could - if practically and economically viable means of achieving this can be developed - reduce current plantation subsidence rates by 25-30%. Whilst some degree of peat subsidence under any form of plantation management may be unavoidable, these reductions would - if achieved at scale - both increase the economic lifetime of the plantations, and simultaneously deliver reductions in CO2 emissions of national and global significance.