Risk of misinterpreting the Tea Bag Index: Field observations and a random simulation
Risk of misinterpreting the Tea Bag Index: Field observations and a random simulation
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DOI：
10.1111/1440-1703.12304
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发表时间：
2022-03-10
影响因子：
2
通讯作者：
Aoyagi, Ryota
中科院分区：
文献类型：
--
作者：
Mori, Taiki;Nakamura, Ryosuke;Aoyagi, Ryota
为了了解人类活动对凋落物分解的全球影响，有必要使用标准化方法获得大型分解数据集。茶袋指数（TBI）方法使用绿色和路易波士茶的质量损失比的单一测量来确定凋落物分解的渐近线模型的分解常数（k）和可水解部分的稳定比（稳定因子S）。这种方法需要假设路易波士茶和绿色茶的S相等。在这里，我们进行了实地实验，在四个温带森林的立场，证明了这一假设并不总是正确的。在石灰岩土壤上的森林中，超过一半的质量损失率的路易波士茶超过了假设和绿色茶数据预测的可分解部分，这意味着S为绿色茶高于路易波士茶。这表明，主要的假设并不总是正确的。我们还进行了随机模拟研究，证明了基于此假设的k的推导导致k和S之间的有偏正关系，无论假设是否正确。因此，我们认为，在同一分析中使用k和S会导致有偏差的结果，因为这些变量在假设下不是相互独立的。应根据使用TBI方法的研究目的考虑这些风险。
To understand the global impact of anthropogenic activities on litter decomposition, it is necessary to obtain large decomposition datasets using a standardized method. The Tea Bag Index (TBI) approach determines the decomposition constant (k) of an asymptote model of litter decomposition and a stabilized ratio of the hydrolyzable fraction (stabilization factor S) using a single measurement of the mass loss ratios of green and rooibos teas. This approach requires the assumption that S is equal for rooibos and green tea. Here, we performed a field experiment in four temperate forest stands that demonstrated that this assumption is not always true. In a forest on limestone soils, more than half of the mass loss ratios of rooibos tea exceeded the decomposable fraction predicted by the assumption and the green tea data, which implies that the S was higher for green tea than rooibos tea. This indicated that the main assumption is not always true. We also performed a random simulation study that demonstrated that the derivation of k based on this assumption leads to a biased positive relationship between k and S, regardless of whether the assumption is correct. Thus, we suggest that the use of k and S in an identical analysis causes biased results because these variables are not independent of each other under the assumption. These risks should be considered depending on the purpose of studies that use the TBI approach.