Litter diversity accelerates labile carbon but slows recalcitrant carbon decomposition



Wang L, Zhou Y, Chen Y, Xu Z, Zhang J, Liu Y & Joly F (2022) Litter diversity accelerates labile carbon but slows recalcitrant carbon decomposition. Soil Biology and Biochemistry, 168, Art. No.: 108632.

In biodiverse ecosystems, leaf litter of different plant species decomposes in mixtures, for which decomposition rates notoriously deviate from that expected from monospecific treatments. Despite important research efforts in past decades, these litter diversity effects remain difficult to predict. We hypothesized that this is due to a focus on bulk litter decomposition, while different carbon fractions constituting the litter may respond differently to litter diversity, thereby blurring the overall response. To test this hypothesis, we determined how the decomposition of (i) soluble compounds, (ii) cellulose, and (iii) lignin responded to litter mixing in a 3.5-year field experiment in an alpine forest. We found that the decomposition of soluble compounds and cellulose in mixtures was faster than expected from monospecific treatments, while that of lignin was slower. These deviations from expected decomposition rates of each litter carbon fraction were driven by different aspects of the litter functional diversity. This suggests that different mechanisms operating on distinct litter fractions lead to synergistic and antagonistic interactions that simultaneously affect bulk litter decomposition. Furthermore, the magnitude of these fraction-specific deviations from expected decomposition rates consistently decreased throughout decomposition. Considering the response of litter fractions and their temporality, rather than focusing on bulk litter thus seems critical to evaluate the response of decomposition to plant diversity and identify underlying mechanisms.

Biodiversity–ecosystem functioning; Carbon fractions; Functional diversity; Litter diversity; Litter quality; Litter mixture

Soil Biology and Biochemistry: Volume 168

FundersNational Natural Science Foundation of China and China West Normal University
Publication date31/05/2022
Publication date online12/03/2022
Date accepted by journal09/03/2022
PublisherElsevier BV

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Dr Francois-Xavier Joly

Dr Francois-Xavier Joly

Lecturer in Soil, Biological and Environmental Sciences