The aim of this study was to assess the effects of the factors controlling the temperature sensitivity of litter decomposition, which is essential for predicting the rate of soil carbon loss in in the context of global climate changes. It based on the translocation of forest litter in a field experiment conducted in the Western Carpathians. Litterbags were used to expose litter originating from different altitudes (i.e., 600, 900, and 1200 m a.s.l.) at the altitude where it was collected and at two other altitudes on five different mountains. Litterbags were collected after 6, 10, and 24 months of exposure. The respiration rate of litter was measured in the laboratory, and Q coefficients were evaluated for two temperature ranges: lower (QL; 5 °C–15 °C) and higher (QH; 15 °C–25 °C). We tested whether litter Q values correlated with experimental factors, as well as soil and microbial community properties. After 24 months of exposure, the litter mass decreased to half of its initial mass. The general linear model (GLM) constructed for Q (R = 77.3 %; p < 0.0001) indicated, that QL values were higher than QH values (2.19 ± 0.58 and 1.52 ± 0.31, respectively) and increased strongly with time (1.56 ± 0.36, 1.73 ± 0.45, and 2.36 ± 0.60, consecutively). There was a significant interaction between the temperature range and time, indicating that QL increased more over time than QH. Other interaction between temperature range and litter origin indicated that QL increased with the altitude of the litter origin, whereas QH did not change. The proportion of fungi in the microbial biomass correlated positively with Q. Our results were consistent with the kinetic theory of higher temperature sensitivity for more decomposed organic matter. The conclusion that litter QL is more responsive to environmental conditions than QH has important implications for estimating soil carbon emissions.

中文翻译：

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温带山区森林凋落物沿海拔梯度分解过程中温度敏感性的变化——一项相互凋落物移植研究

本研究的目的是评估控制凋落物分解温度敏感性的因素的影响，这对于预测全球气候变化背景下土壤碳流失率至关重要。它基于在西喀尔巴阡山脉进行的实地实验中森林垃圾的易位。垃圾袋用于将来自不同海拔高度（即海拔 600、900 和 1200 米）的垃圾暴露在收集地点的海拔高度以及五座不同山上的其他两个海拔高度。暴露 6、10 和 24 个月后收集垃圾袋。在实验室中测量垫料的呼吸速率，并评估两个温度范围的 Q 系数：较低温度（QL；5 °C–15 °C）和较高温度（QH；15 °C–25 °C）。我们测试了凋落物 Q 值是否与实验因素以及土壤和微生物群落特性相关。暴露 24 个月后，垫料质量减少至初始质量的一半。为 Q 构建的一般线性模型 (GLM)（R = 77.3 %；p < 0.0001）表明，QL 值高于 QH 值（分别为 2.19 ± 0.58 和 1.52 ± 0.31），并且随着时间的推移而强烈增加（1.56 ± 0.36） 、 1.73 ± 0.45 和 2.36 ± 0.60，连续）。温度范围和时间之间存在显着的交互作用，表明随着时间的推移，QL 比 QH 增加得更多。温度范围和凋落物起源之间的其他相互作用表明，QL 随着凋落物起源的海拔高度而增加，而 QH 没有变化。微生物量中真菌的比例与 Q 呈正相关。我们的结果与更多分解的有机物对温度敏感性更高的动力学理论一致。凋落物 QL 比 QH 对环境条件更敏感的结论对于估算土壤碳排放具有重要意义。