Aims

In Mediterranean ecosystems fire and drought are two natural disturbances that affect plant traits and generate a highly heterogeneous landscape. The objective of this research was to analyze leaf chemistry, one important driver of carbon and nutrients cycles, and decomposition of Phillyrea angustifolia L. in a landscape affected by recurrent fire disturbance.

Methods

We investigated leaf litter collected in a low-maquis at sites burned by a wildfire 10 years before the current study, at sites burned by an experimental fire 1 year before and at sites located at the edge low-maquis/gaps.

Results

The three litters differed in chemical composition, mass loss and dynamics of lignin/AUR (Acid-Unhydrolizable-Residue), nitrogen and manganese. During the early decomposition phase lignin/AUR increased in litters from sites burned 1 year before and from sites located at the edge low-maquis/gaps and decreased in litter from sites burned 10 years before. Nitrogen and manganese were immobilized in litter during the early and the middle phase of decomposition. ¹³ C NMR spectroscopy revealed that all the litters were rich in Alkyl-C, the fraction including waxes and cutin that are effective barriers to water loss from the leaves. Litter from sites burned 1 year before had the highest hydrophobicity and aromaticity indexes and the highest alkyl ratio, and decomposed at the lowest rate.

Conclusions

Differences of leaf chemical composition within the same plant species across an uneven landscape affect decomposition. The traditional approach and ¹³ C NMR spectroscopy complementarily explain decomposition pattern and give a comprehensive view of the individual drivers of litter decomposition.

中文翻译：

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低地鼠尾草费叶叶片凋落物养分，有机成分和分解模式的差异

目的

在地中海生态系统中，火灾和干旱是影响植物性状并产生高度异质景观的两种自然干扰。这项研究的目的是分析叶片化学，碳和养分循环的重要驱动因素，以及在反复受火干扰影响的景观中费城番荔枝的分解。

方法

我们调查了在本研究之前10年的一场野火烧毁的低垃圾场，在1年之前的一次实验性大火焚烧的站点以及边缘低火候/间隙的站点收集的凋落物。

结果

这三个垃圾的化学成分，质量损失和木质素/ AUR（酸不可水解残基），氮和锰的动力学不同。在分解的早期阶段，木质素/ AUR在1年以前燃烧的场地和边缘低矮动物/空白处的凋落物增加，而在10年以前燃烧的场地的凋落物减少。在分解的早期和中期，将氮和锰固定在垫料中。¹³  C NMR光谱显示，所有的凋落物都富含烷基-C，其中包括蜡和角质的部分是阻止叶片水分流失的有效屏障。在一年前燃烧的场地中，凋落物的疏水性和芳香性指数最高，烷基比率最高，分解率最低。

结论

同一植物物种在不平坦的景观中叶片化学成分的差异会影响分解。传统方法和¹³  C NMR光谱互补地解释了分解模式，并提供了凋落物分解的各个驱动因素的全面视图。