Effects of large-scale environmental disturbances through land-use change and fires on the CO2 balance of tropical peat swamp forest

土地利用变化和火灾造成的大规模环境干扰对热带泥炭沼泽森林二氧化碳平衡的影响

基本信息

批准号：
15255001
负责人：
HIRANO Takashi
金额：
$ 22.88万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Tropical peatlands, which coexist with swamp forests, have accumulated vast amounts of carbon as soil organic matter. Since the 1970s, however, deforestation and drainage have progressed on an enormous scale. In addition, El Nino and Southern Oscillation (ENSO) drought and large-scale fires, which grow larger under the drought condition, are accelerating peatland devastation. That devastation enhances decomposition of soil organic matter and increases the carbon release to the atmosphere as CO_2. This phenomenon suggests that tropical peatlands have already become a large CO_2 source, but related quantitative information is limited. Therefore, we evaluated the CO_2 balance of a tropical peat swamp forest in Central Kalimantan, Indonesia, using three years of CO_2 fluxes measured using the eddy covariance technique from 2002 through 2004. The forest was disturbed by drainage; consequently, groundwater level (GL) was reduced. The net ecosystem CO_2 production (NEP) measurements showed se … More asonal variation, which was slightly positive or almost zero in the early dry season, and most-negative late in the dry season or early the rainy season. This seasonality is attributable to the seasonal pattern of climate, tree phenology and fires. Slightly positive NEP resulted from smaller ecosystem respiration (RE) and larger gross primary production (GPP) under conditions of high photosynthetic photon flux density (PPFD) and large leaf area index (LAI). The most-negative NEP resulted from smaller GPP and larger RE. The smaller GPP was related to high vapor pressure deficit (VPD), small LAI and low PPFD because of smoke from fires. The larger RE was related to low GL. Annual NEP values were estimated respectively as-602,-382 and-313 gC m^<-2> y^<-1> for 2002, 2003 and 2004. These negative NEP values show that the tropical peat swamp forest, disturbed by drainage, functioned as a CO_2 source. That source intensity was highest in 2002, an ENSO year, mainly because of low PPFD caused by dense smoke emitted from large fires. Less

与沼泽森林共处的热带泥炭地已经积累了大量的碳作为土壤有机物。然而，自1970年代以来，森林砍伐和排水量已经增强。此外，在干旱条件下，El Nino和Southern振荡（ENSO）干旱和大规模火灾正在加速梨园的破坏。这种破坏增强了土壤有机物的分解，并将碳释放增加到大气中，如CO_2。这种现象表明，热带峰值已经成为大型CO_2来源，但是相关的定量信息受到限制。因此，我们使用2002年至2004年使用涡流协方差技术测量的三年的CO_2通量评估了印度尼西亚卡利门坦中部热带峰值沼泽森林的CO_2平衡。森林受到排水的干扰。因此，地下水水平（GL）降低。净生态系统CO_2生产（NEP）测量显示了SE…更多的垂直变化，在旱季初期略有正或几乎为零，并且在干旱季节或雨季初期最有效。这种季节性归因于气候，树地和火的季节性模式。在高光合光子通量密度（PPFD）和大叶面积指数（LAI）的条件下，NEP略有阳性NEP是由较小的生态系统呼吸（RE）和较大的总生产（GPP）产生的。最低的NEP是由较小的GPP和较大的RE产生的。较小的GPP与高蒸气压力防御（VPD），小LAI和低PPFD有关。较大的RE与低GL有关。年度NEP值分别估计为AS-602，-382和-313 GC M^<-2> Y^<-1>在2002、2003和2004中。这些负NEP值表明，受到排水影响的热带峰值沼泽森林，起源于CO_2源。该来源强度在2002年，这是ENSO的一年，这主要是由于PPFD较低是由于大火散发出的浓烟而引起的。较少的