Specific leaf area predicts dryland litter decomposition via two mechanisms

Guofang Liu, Lei Wang, Li Jiang, Xu Pan, Zhenying Huang*, Ming Dong, Johannes H.C. Cornelissen

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review

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    Abstract

    Litter decomposition plays important roles in carbon and nutrient cycling. In dryland, both microbial decomposition and abiotic degradation (by UV light or other forces) drive variation in decomposition rates, but whether and how litter traits and position determine the balance between these processes is poorly understood. We investigated relationships between litter quality and their decomposition rates among diverse plant species in a desert ecosystem in vertically contrasting positions representing distinct decomposition environments driven by different relative contributions of abiotic and microbial degradation. Thereto, leaf litter samples from 17 desert species were sealed into litterbags and placed on the soil surface under strong solar exposure vs. shade conditions, or buried in the soil at 10 cm depth, for a whole year. Litter decomposition rates were 21% and 17% higher in burial and light-exposed treatments, respectively, than those in shade. Leaf traits, i.e. specific leaf area (SLA), litter C:N ratio and lignin concentration could predict litter decomposition to some degree, but their predictive power was dependent on litter position. However, multiple linear regressions showed that SLA, litter C and P significantly affected k values for leaf litter decomposition besides litter position, with SLA standing out as a strong determinant of litter decomposition rate as related either to solar radiation or the environment below the soil surface. Furthermore, the interspecific differences in litter decomposition rates decreased over time, implying that afterlife effects of leaf traits on decomposition were attenuated. Synthesis. These findings suggest that abiotic photodegradation and soil burial mediated microbial decomposition could be responsible for higher than expected litter turnover in dryland. They point to a dual role of specific leaf area (SLA) as a promotor of decomposition rates: via relative exposure of the leaf surface to abiotic factors such as UV light vs. to soil moisture and microbes under soil burial.

    Original languageEnglish
    Pages (from-to)218-229
    Number of pages12
    JournalJournal of Ecology
    Volume106
    Issue number1
    Early online date15 Sept 2017
    DOIs
    Publication statusPublished - Jan 2018

    Funding

    We thank L.L. Fan and Y.L. Li in Xinjiang Institute of Ecology and Geography, CAS for their assistance in litter collection, sample preparation and E. Erdenebileg for her chemical analyses. This work was supported by State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences (G2014-02-02), the National Key Research and Development Program of China (2016YFC0500501) and the National Natural Science Foundation of China (NSFC, 31470712). We thank Fukang Station of Desert Ecology, CAS for providing solar radiation and UV radiation data during our experimental period. We are particularly grateful to the two editors, David Wardle and Amy T. Austin, and two anonymous referees for their highly relevant comments to improve the quality and clarity of the manuscript. We also declare that all coauthors have no conflict of interest.

    FundersFunder number
    National Natural Science Foundation of China31470712
    Chinese Academy of Sciences
    Xinjiang Institute of Ecology and Geography, Chinese Academy of SciencesG2014-02-02
    State Key Laboratory of Desert and Oasis Ecology
    National Basic Research Program of China (973 Program)2016YFC0500501

      Keywords

      • desert
      • functional traits
      • litter decomposition rate
      • photodegradation
      • plant–soil (below-ground) interactions
      • soil burial
      • specific leaf area

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