1. Litter decomposition rates are determined by the interplay of climate, decomposer organisms and litter quality. It has been suggested that the decomposer community may be locally adapted to litter quality, providing a home-field advantage (HFA) resulting in accelerated decomposition of local compared to non-local litter, after accounting for decomposition differences due to litter quality and the functional capacity of microorganisms. Although widely tested in forests, this hypothesis remains controversial and lacks a general support of its generality across climates.

2. We therefore tested the HFA hypothesis for litter decomposition in four contrasting ecosystems along an extensive climatic gradient in Chile, using a translocation experiment involving litter from 20 species. In addition to comparing mass loss, we adopted a novel way to disentangle decomposer effects from climate effects, based on loss rates of elements that are actively released from the litter by decomposers during its breakdown vs. elements that are simply leached by precipitation. We used the ratios of nitrogen and potassium losses (N/K loss) and phosphorus and potassium losses (P/K loss) to unravel the relative role of microbial breakdown (N and P loss) vs. physical leaching (K loss) along the climate gradient. Thus, at each site, we tested whether litter mass loss, N/K loss and P/K loss presented an additional loss due to a HFA for local compared to non-local litter.

3. Across a wide range of environments and 20 different litter types, our findings unequivocally contradicted the HFA hypothesis. We observed no significantly positive HFA along the gradient, however litter quality and the general ability of the decomposer community influenced litter decomposition much more strongly than origin or location of the litter.

4. Our study questions the applicability of the HFA for litter decomposition and calls for more studies that include a large range of climatic conditions to understand the context-dependency of HFA.

General description

The dataset is related to the publication “No home-field advantage in litter decomposition from the desert to temperate forest”, by van den Brink et al. 2023 in Functional Ecology. The study aimed at testing the home-field advantage hypothesis in litter decomposition along a climate gradient in Chile. Thus, the dataset comprises litter mass loss data from a translocation experiment with 20 litter species from four study sites (arid, semi-arid, Mediterranean and temperate), where each species was set to decompose in each of the study sites. In addition, the study used the ratios nitrogen to potassium loss (N/K loss) and phosphorus to potassium loss (P/K loss) to account for microbial breakdown (N and P loss) vs. physical leaching (K loss). Therefore, the dataset also contains the nutrient ratios for each mass loss data.

The data of mass loss, N/K and P/K loss were used to calculate the litter ability, soil community ability and home-field effect according to the model presented by Keiser et al. (2014). The information used to run the mentioned model is also included in the dataset.

The Excel file contains two sheets, the first one with the important metadata, and the second one contains the full data.

General methods

Five abundant and representative plant species per site were selected for the experiment. From those species, freshly senesced leaves were handpicked, while still attached to the plants during the dry season preceding the experiment (December 2016-January 2017). Litter was oven-dried at only 45°C for 48h. Five subsamples per litter species were separated from this initial litter and analyzed to determine initial element contents (C, N, P, K) per species. The initial element concentration was averaged at the species level.

1, 2 or 2.5 (±0.005) g of litter of each litter species were bagged in a 2-mm polyester mesh of 10x10cm. Litter bags from all species were then fully reciprocally translocated across the four study sites (20 species * 6 replicate plots * 4 sites) in early May 2017 (late autumn in the southern hemisphere). Bags were placed on top of the mineral soil or the organic layer (if present). The experiment was protected against animals with a poultry-wire mesh cage. All litterbags were retrieved after 12 months, placed in individual paper bags and the remaining litter was weighed after drying at 45°C for 48 h or until constant dry weight. For each sample, the percentage of litter mass loss was calculated as 100*(M0-Mt)/M0, where M0 is the initial dry mass of a sample and Mt is the remaining dry mass after 12 months of decomposition. The remaining litter from each litter bag was stored in individual paper bags and used for further elemental analyses.

The litter was carefully cleaned and mineral soil particles were removed before analysis. Each litter sample was homogenized with a planet ball mill (Pulverisette 5, Fritsch Idar-Oberstein, Germany). The samples were not washed prior to the analysis to avoid loss of leachable elements such as K. Total C and N concentrations were measured by a CNS elemental analyser (Vario EL III, Elementar Analysensysteme GmbH, Langenselbold, Germany), and were used to calculate C/N mass ratios. For details regarding detection limits and quality controls please refer to the Supplementary Data of the publication.

To determine the concentrations of potassium (K) and phosphorus (P), litter samples were dissolved by an acid pressure digestion system (Loftfield PDS-6, Loftfield Analytical Solutions, Neu Eichenberg, Germany). All vessels used were soaked in 10% HCl overnight and rinsed with Millipore water prior to use. Homogenized sample material (target weight: 0.05g) was transferred into Teflon pressure beakers before adding 4mL HNO3 conc. (65%, Merck KGaA, p.a. ≥ 98%). After heating for seven hours at 180°C, digestion solutions were filtered (MN 619 G¼ Ø185 mm, Macherey-Nagel, Düren, Germany) and diluted with Millipore water (Synergy UV ultrapure, Millipore) to a final volume of 50 ml. Digestions were analyzed by an inductively coupled plasma optical emission spectrometer (ICP-OES Optima 5300 DV, PerkinElmer, Wellesley USA) according to EN ISO 11885. Concentrations of P and K (mg kg-1) were calculated and corrected for recovery rates of the certified reference material BCR®-129 (hay powder, Institute for Reference Materials and Measurements). Similarly, the final element mass (mg) of a sample was calculated from the respective element concentration and the sample weight.

The percentage of relative change in element content (K loss (%), N loss (%) and P loss (%)) for a sample was calculated as 100*(averaged initial element mass - final element mass) / averaged initial element mass. Later, the ratios N/K loss and P/K loss were calculated. K loss represents pure leaching effects, typically occurring at the very beginning of the decomposition process (Laskowski et al. 1995). N and P losses representing partially leaching, partially microbial breakdown. The ratios N/K loss and P/K loss, therefore, give an estimate of microbial breakdown, as they standardize N and P losses for leaching effects. Across sites (i.e., across the precipitation gradient), an increase in the ratios represents higher microbial breakdown, as the ratios are standardized for precipitation influence by the precipitation-dependent element (K).

For more details on the methodology, please refer to the main manuscript and supplementary material associated to this dataset.