Differences in nutrients, organic components and decomposition pattern of Phillyrea angustifolia leaf litter across a low maquis

Abstract

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. 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. 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. 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.