DOI: 10.5061/dryad.s458b5n
title: Data from: Intraspecific variation in litter palatability to macroarthropods in response to grazing and soil fertility

description: 1. Clarifying the functional consequences of intraspecific trait
 variability in response to interacting trophic levels would provide a
 significant improvement in our understanding of aboveground-belowground
 linkages. In particular, the effects of grazing on plant traits may
 translate into altered litter quality, with potentially important
 consequences for litter-feeding decomposers. Plant and litter variability
 in response to grazing is expected to depend on soil fertility levels,
 with tolerance and defensive strategies more commonly expressed on fertile
 and poorer soils, respectively. However, how grazing and fertility
 interactively alter litter quality and palatability to detritivores has
 not been explored yet. 2. We conducted a cafeteria experiment with three
 common millipede (Diplopoda) species feeding on leaf litter from two plant
 species, the grass Bromopsis erecta and the forb Potentilla verna. Each
 millipede was offered a binary choice between litter types produced by the
 same plant species, but sampled in plots with distinct herbivory and
 fertilization status: litter originating from grazed areas or from
 one-year sheep exclosures, both in native areas and in adjacent paddocks
 that received chemical N and P fertilization, as well as litter from a
 25-year sheep exclusion in the native area. 3. We found that fertilization
 and herbivore exclusion interactively affected Bromopsis litter quality
 and palatability, whereas Potentilla was much less affected. Bromopsis
 litter palatability was not affected by grazing when litter was collected
 in native plots, except for the long-term exclosure which led to a very
 low palatability. In contrast, and in line with our expectations,
 herbivory was associated with much higher palatability in fertilized
 plots. The changes in palatability were associated with important
 alterations of litter quality. 4. Overall, our study demonstrates that
 intraspecific variation in litter can have profound consequences for soil
 functioning. It emphasizes the role of grazing as a key, but plant
 species-specific factor controlling litter intraspecific variability, and
 its complex interaction with soil fertility level. Moreover, our results
 advocate for a better understanding of the response of the different
 organisms involved in the decomposition process, in particular
 litter-feeding macro-detritivores. We encourage future studies aiming at
 disentangling the various and complex relationships between aboveground
 processes such as herbivory and soil functioning.
description: Litter quality -
 chemistryThis file provides the
 chemical quality data for the litter of Potentilla verna and Bromopsis
 erecta, sampled in the various land use treatments used in the study. Data
 presented are CN, CP, NP, polyphenols (%) and condensed tannins (%). For
 each litter species in each land use treatments, 3 replicates were
 measured, except for polyphenols (only one replicate).Litter quality -
 physical propertiesThis file provides the
 chemical quality data for the litter of Potentilla verna and Bromopsis
 erecta, sampled in the various land use treatments used in the study. Data
 presented are litter thickness (µm) and litter structural resistance
 (J.m-1). For each litter species and each land use treatments, eight
 replcates were measured.Mass loss and
 consumption dataThis file provides the
 mass loss (including control microcosms without detritivores) and the
 litter consumption (logically with NAs for control microcosms without
 detritivores), as well as the individual body mass of the detritivores.
 Mass loss unit = mg.day-1) and consumption unit = mg.g.day-1). Since the
 experiment was made with binary choices, each microcosm is constituted of
 2 litter types(called A and B for clarity). A litter type is a litter
 species collected in a given land use treatment (fertilization - grazing).
 Mass loss was recorded for three millipede species (GM = Glomeris
 marginata, OR = Ommatoiulus rutilans, CC = Cylindroiulus caerulocinctus)
 and two litter species (Bromopsis erecta ex Bromus erectus and Potentilla
 verna). The land use treatments are exposed in detail in the
 article.