Spatial Variability of Annual Estimates of Methane Emissions in a Phragmites Australis (Cav.) Trin. ex Steud. Dominated Restored Coastal Brackish Fen
Spatial Variability of Annual Estimates of Methane Emissions in a Phragmites Australis (Cav.) Trin. ex Steud. Dominated Restored Coastal Brackish Fen
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DOI：
10.1007/s13157-014-0528-z
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发表时间：
2014-03
期刊：
影响因子：
2
通讯作者：
S. Koch;G. Jurasinski;F. Koebsch;M. Koch;S. Glatzel
中科院分区：
文献类型：
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作者：
S. Koch;G. Jurasinski;F. Koebsch;M. Koch;S. Glatzel
甲烷是一种主要的温室气体，在100年的时间范围内，其全球变暖潜力比二氧化碳高25倍。确定年度排放量估计数，通常是为特定土地使用下的不同植被类型规定的，需要使用室内测量。由于生态系统中测量点的空间安排，这些排放量估计数可能会严重偏向低端或高端。在这里，我们分析的空间变异性的基础上，非稳态封闭室测量纯和混合林芦苇（Cav.）崔恩·前斯特德。在一个恢复的沿海半咸水沼泽中。每个测量点的年甲烷排放量估计值在46和1，329 kg ha−1a− 1CH4之间变化很大，但在纯林和混交林之间没有显著差异。澳大利亚。Mantel检验表明，点间距离与甲烷排放量估计值的变化存在显著相关性（p< 0.05）。水位和年甲烷排放量估计的空间相关性不显着。经验变差函数表明，每年的甲烷排放量估计的方差不随空间距离的增加而增加。然而，距离较远的地点的年度甲烷排放量估计可能会有很大差异。与此同时，共享较小距离的地点尽管这些地点超过了许多封闭室测量装置的共同距离，但它们的年度甲烷排放量估计值差异较小。因此，当在封闭室研究中使用典型的测量位置集群布置时，可能会错过特定生态系统或植被类型中年度甲烷排放量的大部分自然变化。因此，我们建议，测量位置应涵盖广泛的空间范围，以提高每年的排放量估计的可靠性，每种植被类型和生态系统，测量位置的数量应尽可能通过预先研究确定。
Methane is a major greenhouse gas with a global warming potential 25 times higher than carbon dioxide over a 100 year time horizon. Determining annual emission estimates, usually specified for different vegetation types under particular land use, requires the use of chamber measurements. These emission estimates may be strongly biased towards the lower or upper end by the spatial arrangement of measurement spots in the ecosystem. Here, we analyze the spatial variability of annual methane emission estimates based on non-steady state closed chamber measurements in pure and mixed stands ofPhragmites australis(Cav.) Trin ex Steud. in a restored coastal brackish fen. Annual methane emission estimates per measurement location vary largely between 46 and 1,329 kg ha−1a−1CH4but they do not differ significantly between pure and mixed stands ofP. australis. Mantel tests show a significant correlation of distances between spots and the variation in methane emission estimates (p< 0.05). Spatial correlation of water levels and annual methane emission estimates is not significant. Empirical variograms suggest that variance in annual methane emission estimates is not increasing with increasing spatial distance. However, spots that share larger distances may differ considerably in their annual methane emission estimates. At the same time, spots that share smaller distances–though these exceed the distances common to many closed chamber measurement setups–may differ less in their annual methane emission estimates. Thus, a huge part of the natural variation in annual methane emissions in a particular ecosystem or vegetation type may be missed when using the typical clustered arrangement of measurement locations in closed chamber studies. Therefore, we suggest that measurement locations should cover a wide spatial extent to improve the reliability of annual emission estimates per vegetation type and ecosystem, and that the number of measurement locations appropriate should be determined by pre-studies whenever possible.