Abstract
Leaf litter decomposition is a key process in stream ecosystems, the rates of which can vary with changes in litter quality or its colonization by microorganisms. Decomposition in streams is increasingly used to compare ecosystem functioning globally, often requiring the distribution of litter across countries. It is important to understand whether litter sterilization, which is required by some countries, can alter the rates of decomposition and associated processes. We examined whether litter sterilization with gamma irradiation (25 kGy) influenced decomposition rates, litter stoichiometry, and colonization by invertebrates after weeks of instream incubation within coarse-mesh and fine-mesh litterbags. We used nine plant species from three families that varied widely in litter chemistry but found mostly consistent responses, with no differences in decomposition rates or numbers of invertebrates found at the end of the incubation period. However, litter stoichiometry differed between irradiated and control litter, with greater nutrient losses (mostly phosphorus) in the former. Therefore, the effects of irradiation on litter chemistry should be taken into account in studies focused on stoichiometry but not necessarily in those focused on decomposition rates, at least within the experimental timescale considered here.
Highlights
The process of leaf litter decomposition is considered a good indicator of stream ecosystem functioning and integrity (Gessner & Chauvet, 2002; von Schiller et al, 2017) and is increasingly a focus of continental and global studies assessing the ecological consequences of climate change (Boyero et al, 2011), organic pollution (Woodward et al, 2012), land-use change (Ferreira et al, 2018), and biodiversity loss (Handa et al, 2014)
We examined the effect of litter irradiation on the following variables for litter incubated in coarse-mesh and fine-mesh litterbags: (1) decomposition, measured as proportional litter mass loss (LML), calculated as the difference between initial and final ash-free dry mass (AFDM) divided by initial AFDM; (2) nutrient stoichiometry, measured through carbon (C):N, C:P, and N:P molar ratios at the end of the experiment; and (3) invertebrate colonization, measured through the abundance and taxonomic richness of all invertebrates and of litterconsuming detritivores found at the end of the experiment
We found no effects of irradiation on decomposition for any plant family in coarse-mesh and fine-mesh litterbags (Table 1)
Summary
The process of leaf litter decomposition is considered a good indicator of stream ecosystem functioning and integrity (Gessner & Chauvet, 2002; von Schiller et al, 2017) and is increasingly a focus of continental and global studies assessing the ecological consequences of climate change (Boyero et al, 2011), organic pollution (Woodward et al, 2012), land-use change (Ferreira et al, 2018), and biodiversity loss (Handa et al, 2014) These studies have been conducted through the coordinated work of multiple researchers and have generally involved incubating particular selected combinations of leaf litter in streams distributed worldwide, providing answers to globally relevant questions that are otherwise difficult to address (Boyero & Pearson, 2017). While an alternative to the collection and distribution of litter is the use of standard, non-natural substrates such as cotton strips (Tiegs et al, 2019), this is only possible when the focus is on microbial decomposition because these substrates are not processed by invertebrates, which are major agents of litter decomposition (Boyero et al, 2021c)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
