DOI: 10.5061/dryad.c59zw3rd9
title: Data from: Effects of mixing litter on decomposition under three exposure scenarios

description: The effect of mixing litter on decomposition has received considerable
 attention in terrestrial and aquatic (but rarely in both) ecosystems, with
 a striking lack of consensus in the obtained results. We studied the
 decomposition of a mixture of poplar and alder in three
 terrestrial:aquatic exposures to determine (1) if the effect of mixing
 litter on mass loss, associated decomposers (fungal biomass, sporulation
 rates, and richness) and detritivores (abundance, biomass, and richness of
 invertebrate shredders) differs between the stream (fully aquatic
 exposure) and when litter is exposed to a period of terrestrial exposure
 prior to immersion and (2) the effect of the mixture across exposure
 scenarios. The effect of the mixture was additive on mass loss and
 synergistic on decomposers and detritivores across exposure scenarios.
 Within scenarios, mass loss and decomposers showed synergistic effects
 only in the fully aquatic exposure, detritivores showed synergistic
 effects only when the period of terrestrial was shorter than the period of
 aquatic exposure, and when the period of terrestrial was equal to the
 period of aquatic exposure the effect of the mixture was additive on mass
 loss, decomposers, and detritivores. The species-specific effects also
 differed among exposure scenarios. Alder affected poplar only when there
 was a period of terrestrial exposure, with increased sporulation rates and
 fungal richness in exposure 25:75, and increased mass loss in exposure
 50:50. Poplar affected alder only under fully aquatic exposure, with
 increased mass loss. In conclusion, the synergistic effects of the mixture
 changed with a period of terrestrial exposure prior to immersion. These
 results provide a cross-boundary perspective on the effect of mixing
 litter, showing a legacy effect of exposure to terrestrial decomposition
 on the fate of plant litter in aquatic ecosystems and highlighting the
 importance of assessing the effect of mixing litter on the associated
 biota and not only on mass loss.
description: The study site and the litter decomposition
 study are described in detail in Abelho, M. & Descals, E. (2019).
 Litter movement pathways across terrestrial–aquatic ecosystem boundaries
 affect litter colonization and decomposition in streams.
 <em>Functional Ecology</em>, <em>33</em>,
 1785–1797. https://doi.org/10.1111/1365-2435.13356. Mean deviation between observed values in the mixture and the average of the single species was assessed with the relative mixture effect (RME). Mean deviation between the values of a species in the mixture and that single species was assessed with the relative individual performance (RIP).
description: Data are provided in an open access spreadsheet (ods).
description: # **Effects of mixing litter on decomposition under three exposure
 scenarios** Data are values of mass loss, ergosterol content, sporulation
 rates, fungal richness, shredder biomass, abundance, and richness,
 associated with leaves decomposing in three exposure scenarios to
 determine the effect of mixing litter (1:1 mixture of *Alnus glutinosa*
 (L.) Gaertn. and *Populus × canadensis* Moench) on decomposition
 **Exposure scenario**. The litterbags were incubated in three
 terrestrial-aquatic exposure scenarios. * **0:100** – 0 days terrestrial;
 56 days aquatic (stream) * **25:75** – 14 days terrestrial; followed by 42
 days in the stream. * **50:50** – 28 days terrestrial followed by 28 days
 in the stream. **RME.** Relative Mixture Effect: comparison of the values
 in the mixture with the average of the two single species. **RIP.**
 Relative Individual Performance: comparison of a species in the mixture
 with that species alone. **n/a.** There are no values because there was
 not enough leaf material to determine fungal colonization parameters:
 ergosterol (estimate of fungal biomass) and sporulation rates.  ####
 Description of the data and file structure There are two sheets, one with
 the data for the Relative Mixture Effect (RME) and the other with the data
 for the Relative Individual Performance (RIP). #### Usage notes Data are
 provided in an open access spreadsheet (ods).