DOI: 10.5061/dryad.1vhhmgr7f
title: Data and code from: Inverse effects of soil moisture and litter quality on litter decomposition along a gradient from hyper-arid to temperate climate

description: Litter decomposition, a key component of the global carbon cycle, is
 greatly affected by climate. Our current understanding of climate-change
 effects on decomposition stems from 1) spatial observational studies along
 climate gradients, where direct and indirect effects of climate on litter
 decomposition are confounded; 2) reciprocal litter translocations and
 common garden experiments, where biotic interactions are disrupted or 3)
 manipulation experiments, which can be less realistic than observational
 studies. Experimental studies combining all of the above-mentioned methods
 can separate indirect from direct climate effects on decomposition, as the
 confounding effects of one method can be explained with another method.
 Additionally, this setup can directly test if observations along a spatial
 gradient can predict responses to climate change, i.e. the validity of the
 space-for-time approach. However, studies combining the different methods
 are still scarce. We combined a pronounced climate gradient, large- and
 small-scale reciprocal litter translocations (local litter and standard
 litter, i.e. tea), and in situ precipitation manipulation for studying
 soil moisture effects on litter decomposition. All our experiments
 (translocation of litter and tea across the gradient, slope comparisons
 within sites, and rainfall exclusions) indicated positive direct effects
 of climate on litter decomposition. However, as local litter quality
 decreased with increasing precipitation, litter from species of the drier
 sites decomposed quicker than litter from species of the wetter sites
 across the gradient. In other words, while the direct effects of climate
 favoured litter decomposition in wetter sites, its indirect effect (i.e.
 litter quality) favoured the decomposition of litter from species of the
 drier sites within each site. Synthesis: Our results highlight the need
 for experimental evidence from reciprocal translocations and climate
 manipulations in litter decomposition studies as they indicate that space
 cannot always substitute for time. Such evidence would improve predictions
 of models of the global carbon cycle that include interactions between
 climate and vegetation.
description: At each site, we selected five abundant and representative native
 species, making sure the species provided a considerable fraction of the
 litter input. (arid: <em>Heliotropium pycnophyllum</em> Phil.,
 <em>Nolana crassulifolia</em> Poepp., <em>Nolana
 mollis</em> I.M. Johnst., <em>Ophryosporus
 triangularis</em> Meyen, <em>Tetragonia maritima</em>
 Barnéoud; semi-arid: <em>Cordia decandra</em> Hook. &
 Arn., <em>Flourensia thurifera</em> (Molina) DC,
 <em>Lobelia polyphylla</em> Hook. & Arn.,
 <em>Maytenus boaria</em> Molina, <em>Senna
 cumingii</em> (Hook. & Arn.) H.S. Irwin; Mediterranean:
 <em>Aristeguietia salvia</em> (Colla) R.M. King & H.
 Rob., <em>Cestrum parqui</em> (Lam.) L`Hér., <em>Jubaea
 chilensis</em> (Molina) Baill., <em>Podanthus
 mitiqui</em> Lind., <em>Quillaja saponaria</em> Molina;
 temperate: <em>Araucaria araucana</em> (Molina) K. Koch,
 <em>Chusquea culeou</em> É. Desv., <em>Festuca sp.,
 Nothofagus antarctica</em> (G. Forst.) Oerst., <em>Usnea
 sp.</em>). In addition, Lipton® green tea (<em>Camellia
 sinensis</em>, EAN Nr.: 8 722700 055525, from here on “tea”) was
 used as a standard litter (Keuskamp, Dingemans, Lehtinen, Sarneel,
 & Hefting, 2013) to separate the influence of the decomposition
 environment from the climate effects, and make the study comparable to
 other decomposition studies. Litterbags of all species
 were fully reciprocally distributed along the climate gradient and placed
 in the independent plots on dry and wet exposures together with two tea
 bags per plot. Litter and tea bags were collected at three points in time
 to account for the temporal dynamics of decomposition: after 3, 6, and 12
 months. Only local species (species occurring at the
 manipulated sites) and tea were used in the drought in-situ climate
 manipulation experiment. All retrieved bags were dried
 at 40 °C for at least 72 hours until stable weight, after which the
 remaining litter was weighed. Mass loss was calculated as a proportion of
 the initial weight: (dry weight<sub>initial</sub> - dry
 weight<sub>end</sub>) / dry
 weight<sub>initial</sub>. Carbon to
 nitrogen ratio (C/N) were used as a proxy for litter quality.
 For more details on the methodology, please refer to the
 associated article and supplementary material associated to this
 dataset.
description: # Inverse effects of soil moisture and litter quality on litter
 decomposition along a gradient from hyper-arid to temperate climate van
 den Brink, Liesbeth*^1,2, 3^; Canessa, Rafaella^4,5,6^; Bader, Maaike
 Y.^4^; Neidhardt, Harald^7^; Oelmann, Yvonne^7^: Cavieres, Lohengrin
 A.^2,8^; Tielbrger, Katja ^1^ ^1^Plant Ecology Group, Department of
 Biology, University Tbingen, Germany. ^2^ECOBIOSIS, Department of Botany,
 University of Concepcin, Concepcin, Chile. ^3^Institute of Botany,
 Department of Ecosystem Management, Climate and Biodiversity, BOKU
 University, Austria. ^4^Ecological Plant Geography, Faculty of Geography,
 University of Marburg, Germany. ^5^German Centre for Integrative
 Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
 ^6^Institute of Biology/Geobotany and Botanical Garden, Martin Luther
 University Halle-Wittenberg, Halle (Saale), Germany ^7^Geoecology,
 Department of Geosciences, University Tbingen, Germany. 8Institute of
 Ecology and Biodiversity (IEB), Santiago, Chile.
 *[LiesbethvandenBrink78@gmail.com](mailto:LiesbethvandenBrink78@gmail.com)
 [rcaness1@uc.cl](mailto:rcaness1@uc.cl);
 [maaike.bader@gmail.com](mailto:maaike.bader@gmail.com);
 [harald.neidhardt@uni-tuebingen.de](mailto:harald.neidhardt@uni-tuebingen.de); [yvonne.oelmann@uni-tuebingen.de](mailto:yvonne.oelmann@uni-tuebingen.de); [lcaviere@udec.cl](mailto:lcaviere@udec.cl); [katja.tielboerger@uni-tuebingen.de](mailto:katja.tielboerger@uni-tuebingen.de). Corresponding author: Liesbeth van den Brink Journal Name: Journal of Ecology ## Description of the data and file structure: ### General description The datasets are related to the publication Inverse effects of soil moisture and litter quality on litter decomposition along a gradient from hyper-arid to temperate climate, by van den Brink et al. 2025 in Journal of Ecology. The study aimed at testing the applicability of the space-for-time substitution 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) and green tea, where each species was set to decompose in each of the study sites. In addition, the dataset comprises litter mass loss data from an in-situ climate manipulation experiment in the two central sites (semi-arid and mediterranean) where 5 local litter of these sites and green tea were set to decompose under rainout shelters. The rainout shelters simulated the precipitation of the adjacent drier site: mediterranean drought simulated semi-arid precipitation; semi-arid drought simulated arid precipitation. This data helps to understand if short term climate change has similar effects as long tern climate change. There are 2 Excel files. File 1 contains microclimate data and has three sheets, the first one with the important metadata, the second one contains the full data, and the third contains the soil moisture formulas used to calculate the volumetric soil moisture. File 2 contains the decomposition data and has eight sheets. The first one with important metadata, the second contains the data of litterbag material comparison, the third and fourth contain the datasets of the decomposition of tea (sheet 3) and litter (sheet 4) along the gradient, the fifth and sixth contain the datasets of the decomposition of tea (sheet 5) and litter (sheet 6) in the drought experiments, the seventh contains the data of the decomposition of local species at their home site, and the eight contains the data of the C/N ratios of the species used in this study. ### General methods At each site, we selected five abundant and representative native species, making sure the species provided a considerable fraction of the litter input. (arid: *Heliotropium pycnophyllum* Phil., *Nolana crassulifolia* Poepp., *Nolana mollis* I.M. Johnst., *Ophryosporus triangularis* Meyen, *Tetragonia maritima* Barnoud; semi-arid: *Cordia decandra* Hook. & Arn., *Flourensia thurifera* (Molina) DC, *Lobelia polyphylla* Hook. & Arn., *Maytenus boaria* Molina, *Senna cumingii* (Hook. & Arn.) H.S. Irwin; mediterranean: *Aristeguietia salvia* (Colla) R.M. King & H. Rob., *Cestrum parqui* (Lam.) L`Hr., *Jubaea chilensis* (Molina) Baill., *Podanthus mitiqui* Lind., *Quillaja saponaria* Molina; temperate: *Araucaria araucana* (Molina) K. Koch, *Chusquea culeou* . Desv., Festuca sp., *Nothofagus antarctica* (G. Forst.) Oerst., *Usnea sp*.; for further details, such as a family and growth-form, see Supplementary table S2). Senescent leaves, still attached to the plants to minimize contamination with on-site soil microbes, were collected from 15-30 randomly selected individuals of each species during the dry season (December 2016 - January 2017) and thoroughly mixed in one pool per species. In addition, Lipton green tea (Camellia sinensis, EAN Nr.: 8 722700 055525, from here on tea) was used as a standard litter (Keuskamp, Dingemans, Lehtinen, Sarneel, & Hefting, 2013) to separate the influence of the decomposition environment from the climate effects, and make the study comparable to other decomposition studies. The collected litter and tea bags were dried to a stable weight for 72 hours at 40C, and depending on leaf size, leaf weight and availability of dry litter 1, 2, or 2.5 g ( 0.005 g, the exact initial weight was recorded) were bagged in 2 mm polyester mesh. When leaves were very small, brittle, or had the tendency to pass through the mesh, an additional layer of 2 mm mesh was used. No significant differences in decomposition were detected when both types of bags were used (Supplementary table S3). Litterbags and teabags were randomly assigned to a site where they were placed at ground level, on top of the mineral soil (arid and semi-arid sites, where a litter layer was not present) or on top of litter layer (mediterranean and temperate sites) between 11 and 29 May 2017, just before the first rains of the season (May August). We did not control for light exposure, which varied along the gradient (bernickel et al., 2020), as a parallel study (Canessa et al., 2021) found that photodegradation was not a significant contributor to decomposition at the arid site. Litterbags of all species were fully reciprocally distributed along the climate gradient and placed in the independent plots on dry and wet exposures (20 species * 3 replicates * 3 retrievals * 3 plots * 2 exposures * 4 sites), together with two tea bags per plot (2 replicates * 3 retrievals * 3 plots * 2 exposures * 4 sites). Litter and tea bags were collected at three points in time to account for the temporal dynamics of decomposition: after 3, 6, and 12 months (931; 1954; 3665 days), respectively. Only local species (species occurring at the manipulated sites) and tea were used in the drought in-situ climate manupulation experiment. Litterbags (5 species * 3 replicates * 3 retrievals * 3 plots * 2 rainfall treatments * 2 exposures * 2 sites), as well as tea bags (2 replicates * 3 retrievals * 3 plots * 2 rainfall treatments * 2 exposures * 2 sites) were placed in drought- and control plots and collected after 3-, 6-, and 12 months (931; 1954; 3665 days), respectively. All retrieved bags were dried at 40C for at least 72 hours until stable weight, after which the remaining litter was weighed. Mass loss was calculated as a proportion of the initial weight: (dry weightinitial - dry weightend)/dry weightinitial. Carbon to nitrogen ratio (C/N) were used as a proxy for litter quality. Total carbon (Ct, detection limit 0.1 weight percent (wt %)) and nitrogen (Nt, detection limit 0.03 (wt %)) contents of homogenized (planetary ball mill, Pulverisette 5, Fritsch) initial litter samples (i.e. before decomposition) were analyzed with an Element Analyzer (Vario EL III, Elementar Analysensysteme GmbH). For more details on the methodology, please refer to the associated publication and supplementary material associated to this dataset. ### Data description There are 2 data files available. File 1 contains microclimate data (Microclimate_data.xlsx), file 2 decomposition data (Decomposition_files.xlsx). | Microclimate\_data.xlsx | 
 
 | | :--------------------------- |
 :----------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Microclimate** | **Description** | | Location | Location (study site) of microclimate measurements. Arid, Semi-arid, Mediterranean, Temperate. | | Exposure | Exposure of microclimate measurements. SF = South (pole) facing, NF = North (equator) facing. | | Plot | Plot of microclimate measurements.  | | Year | Year of microclimate measurements. | | Month | Month of microclimate measurements. | | T -5 | Temperature (°C) measurements at a depth of 5cm in the soil. | | T 0 | Temperature (°C) measurements at the surface of the soil. | | T +5 | Temperature (°C) measurements at a height of 5 cm above the soil, in the air. | | Soil\_moisture\_count | Raw soil moisture count of microclimate measurements. | | Volumetric soil moisture | m3/m3. Transformed soil moisture count, calculated with the formulas indicated in the Soil moisture transformation tab. | | Treatment | Ambient vs drought conditions.  | | 
 
 | 
 
 | | Soil moisture transformation | Description | | Location | Study site
 of microclimate measurements. Arid, Semi-arid, Mediterranean, Temperate. |
 | Soil composition | The calibration curves based on soil composition used
 to transform the raw soil moisture count data into volumetric soil
 moisture with the Calibr tool from TOMST. | | Transformation formula | The
 formula indicated by the Calibr tool from TOMST according to the soil
 composition in each location. | 
 
 | Decomposition\_files.xlsx | 
 
 | | :------------------------ |
 :--------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **In all tabs** | **Description** | | Species | Plant litter species included in the litterbag (observation) | | Mass loss (%) | Percentage of mass loss of a litterbag (observation), calculated as (Final weight  - Initial weight) / Initial weight \* 100 | | Origin of litter | Study site where the litter of a plant species was collected. Arid, Semi-Arid, Mediterranean, Temperate | | Days in Field | Amount of days that the litterbags were decomposing on site. | | Months in Field | Amount of months that the litterbags were decomposing on site. | | Material Litterbag | Material used to make the litterbags. Both meshes were 2mm, the normal material was a bit tougher and less flexible, while the mosquito mesh was more flexible.  | | Layers | Layers of material used in the litterbags. 1 or 2. | | Location of decomposition | Location (study site) of decomposition for a given observation.  AR=Arid, SA=Semi-Arid, ME=Mediterranean, TE=Temperate | | Exposure | Exposure of decomposition for a given observation. SF = South (pole) facing, NF = North (equator) facing. | | Plot | Plot of decomposition for a given observation. | | Drought treatment | Treatment of decomposition for a given observation. Control = ambient conditions, Drought = precipitation reduction with passive rainout shelter. | | C:N ratio | Ratio between carbon and nitrogen content of the litter before it was deployed in the field. | **Code** JMP code is available in file JMP_code.txt Funding Information: This study was funded by the German Research Foundation (DFG) Priority Program SPP-1803 EarthShape: Earth Surface Shaping by Biota (BA 3843/6-1, NE 1852/3-2, OE 516/7-1 and -2, and TI 338/14-1 and -2) and additional support from CONICYT PIA CCTE AFB-17008 and ANID-FB210006 funding the Institute of Ecology and Biodiversity (Chile). Related work: van den Brink, L., Canessa, R., Neidhardt, H., Knver, T., Rios, R S., Saldaa, A., Cavieres, L A., Oelmann, Y., Bader, M Y., & Tielbrger, K. (2023). No home-field advantage in litter decomposition from the desert to temperate forest. Functional Ecology, 37, 13151327. [https://doi.org/10.1111/1365-2435.14285](https://doi.org/10.1111/1365-2435.14285) ##