Leaf litter decomposition plays an important role in nutrient and carbon cycling in terrestrial ecosystems. However, at a global scale, the effects of climate, initial litter chemistry, and different plant functional types on litter decomposition are not fully understood. Additionally, it remains unclear whether the effects of litter chemistry on leaf litter decomposition are consistent with responses observed at local scales. Here, 1585 observations of leaf litter decomposition encompassing 861 species from 298 field studies were synthesized to investigate the effects of climate, litter initial chemistry, and various plant groups on decomposition rates. The results demonstrate that at a global scale, leaf litter decomposition rates increased with mean annual temperature (MAT), mean annual precipitation (MAP), initial litter concentrations of nitrogen (N), phosphorus (P), and magnesium (Mg), but decreased with initial lignin concentrations. Moreover, except for initial leaf litter Mg concentrations, the influence of initial leaf litter chemistry characteristics on decomposition rates were consistent at global and local scales. In woody plants, leaf litters from deciduous, broadleaf, and arbuscular mycorrhizal (AM) species exhibited faster decomposition rates than from evergreen, coniferous, and ectomycorrhizal (ECM) species leaf litters, respectively. In herbaceous plants, the leaf litter of forbs had faster decomposition rates than graminoid and leguminous plants. For all plants, leaf litter decomposition is primarily controlled by MAP and MAT globally, while for woody and herbaceous plants, leaf litter decomposition is primarily controlled by initial leaf N and P concentrations, respectively. These results indicated that various functional groups of plants play a crucial role in understanding the decomposition of leaf litter. Moreover, when investigating the effect of leaf litter initial chemistry on its decomposition, it is almost unnecessary to consider effects at different scales.

中文翻译：

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陆生凋落叶分解的全球格局：气候、凋落物化学、生命形式、生长形式和菌根关联的影响


凋落叶分解在陆地生态系统的养分和碳循环中起着重要作用。然而，在全球范围内，气候、初始凋落物化学和不同植物功能类型对凋落物分解的影响尚不完全清楚。此外，目前尚不清楚凋落物化学对凋落叶分解的影响是否与在局部尺度上观察到的反应一致。在这里，综合了 1585 次凋落叶分解观察，包括来自 298 个田间研究的 861 个物种，以研究气候、凋落物初始化学和各种植物群对分解速率的影响。结果表明，在全球范围内，凋落叶分解速率随年平均温度 （MAT）、平均年降水量 （MAP）、氮 （N）、磷 （P） 和镁 （Mg） 的初始凋落物浓度的增加而增加，但随着木质素的初始浓度而降低。此外，除初始凋落叶 Mg 浓度外，初始凋落叶化学特性对分解速率的影响在全球和局部尺度上是一致的。在木本植物中，落叶、阔叶和丛枝菌根 （AM） 物种的凋落叶分别比常绿、针叶和外生菌根 （ECM） 物种的凋落叶表现出更快的分解速率。在草本植物中，杂草的凋落叶比禾本科植物和豆科植物具有更快的分解速率。对于所有植物，凋落叶分解主要受 MAP 和 MAT 在全球范围内控制，而对于木本和草本植物，凋落叶分解主要分别受初始叶片 N 和 P 浓度控制。 这些结果表明，植物的各种功能群在理解凋落叶的分解中起着至关重要的作用。此外，在研究凋落叶初始化学对其分解的影响时，几乎没有必要考虑不同尺度上的影响。