Detritivore conversion of litter into faeces accelerates organic matter turnover

• Published in: Communications biology 2020-11, Vol.3 (1), p.660-660, Article 660
• Main Authors: Joly, François-Xavier, Coq, Sylvain, Coulis, Mathieu, David, Jean-François, Hättenschwiler, Stephan, Mueller, Carsten W., Prater, Isabel, Subke, Jens-Arne
• Format: Article
• Language: English
• Subjects: 631/158/2445; 631/158/47/4113; Biogeochemistry; Biology; Biomedical and Life Sciences; Carbon; Carbon cycle; Decomposition; Detritivores; Feces; Lability; Leaf litter; Life Sciences; Organic matter; Organic soils; Phylogeny; Species
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-020-01392-4

Litter-feeding soil animals are notoriously neglected in conceptual and mechanistic biogeochemical models. Yet, they may be a dominant factor in decomposition by converting large amounts of plant litter into faeces. Here, we assess how the chemical and physical changes occurring when litter is converted into faeces alter their fate during further decomposition with an experimental test including 36 combinations of phylogenetically distant detritivores and leaf litter of contrasting physicochemical characteristics. We show that, across litter and detritivore species, litter conversion into detritivore faeces enhanced organic matter lability and thereby accelerated carbon cycling. Notably, the positive conversion effect on faeces quality and decomposition increased with decreasing quality and decomposition of intact litter. This general pattern was consistent across detritivores as different as snails and woodlice, and reduced differences in quality and decomposition amongst litter species. Our data show that litter conversion into detritivore faeces has far-reaching consequences for the understanding and modelling of the terrestrial carbon cycle. By performing an ecologically relevant experiment with variety in litter composition and detritivore species, Joly et al. find that litter conversion into faeces has a profound effect on organic matter lability and decomposition. These findings have implications for biogeochemical models of carbon cycling.