DOI: 10.5061/dryad.573n5tbm5
title: Plant production decreases more than litter decomposition with rising aridity in drylands

description: Climate change increases aridity in many drylands worldwide, which has
 significant consequences for ecosystem functioning and may reduce carbon
 sequestration. However, responses of major carbon cycle processes in
 drylands, including primary production and decomposition, to increasing
 aridity remain poorly understood. In this study, we assessed the
 quantitative effects of precipitation and the underlying impacts of
 functional traits on aboveground net primary production (ANPP) and plant
 litter decomposition in herbaceous Mediterranean plant communities. A
 dataset encompassing a wide range of precipitation (~50-1000 mm) was
 generated by selecting four field sites along a natural precipitation
 gradient, applying rainfall manipulations, and conducting the experiment
 over 3-9 years. Across the entire dataset, ANPP and decomposition
 decreased non-linearly with declining precipitation, showing steeper
 reductions at low compared to high precipitation levels. Notably, above
 ~400 mm, the two processes followed a similar pattern, but below this
 threshold, ANPP dropped more rapidly, while decomposition decreased less
 and remained relatively high. Plant functional traits associated with low
 growth rates exacerbated the reduction of ANPP at the drier sites, whereas
 higher litter quality at these sites compared with the wetter sites
 enabled relatively high rates of litter decomposition. The latter findings
 were confirmed by a litter transplantation study, where litter from the
 arid site decomposed faster at all sites compared to litter from the
 wetter sites. In addition, dryland decay mechanisms, such as
 photodegradation and microbial degradation enabled by non-rainfall water
 sources might have mitigated some of the dryness-related decrease in
 decomposition. Increasing climate change-induced aridity in drylands may
 drive long-term shifts in herbaceous vegetation composition toward
 smaller, less productive species that produce more labile litter. This
 trend is expected to accelerate the decline in production more than the
 decline in decomposition, likely reducing carbon sequestration.
description: # Plant production decreases more than litter decomposition with rising
 aridity in drylands Dataset DOI:
 [10.5061/dryad.573n5tbm5](10.5061/dryad.573n5tbm5) ## **Study
 Description** The dataset was collected within a long-term field
 experiment along a precipitation gradient in Israel, covering four sites
 with mean annual rainfall between 90 and 780 mm. The study focused on
 herbaceous plant communities. At two sites, precipitation was
 experimentally manipulated (+30% and –30% rainfall), while the other two
 sites served as controls. Aboveground net primary production (ANPP) was
 assessed annually by destructive biomass harvest in permanent plots over 9
 years. Litter decomposition was measured using litterbags deployed in the
 field and in reciprocal transplantation experiments across sites. Plant
 and litter functional traits were determined for dominant species and
 representative litter samples. The data include biomass production,
 decomposition rates, plant and litter chemical and structural traits, and
 precipitation treatments. All files are provided in unformatted,
 open-access CSV format for accessibility and ease of re-analysis. --- ##
 **Files and Variables** ### **Files: Traits** **Description**:
 Community-weighted means of functional traits for dominant plant species
 and corresponding litter at each site and year. **File:
 Traits_Leaf_traits.csv** * Site – Site name (text) * Year – Year of
 sampling (YYYY) * Canopy Height (cm) – Mean plant canopy height (cm) * SLA
 (cm²/kg) – Specific leaf area (cm² per kg) * Leaf N concentration (%) –
 Leaf nitrogen concentration (%) * Leaf C/N ratio – Carbon-to-nitrogen
 ratio (unitless) **File: Traits_Litter_traits.csv** * Site – Site name
 (text) * Year – Year of sampling (YYYY) * N% – Nitrogen content of litter
 (%) * C/N – Carbon-to-nitrogen ratio in litter (unitless) * Lignin % –
 Lignin content in litter (%) * Lignin/N – Lignin to nitrogen ratio
 (unitless) * P % – Phosphorus content in litter (%). Missing values are
 blanks. --- ### **Files: Local decomposition** **Description**: Litter
 decomposition data for both local and reciprocal litter decomposition
 experiments across sites, treatments, and years. **File:
 Decomposition_Local_litter.csv** * Site – Site name (text) * Treatment –
 Rainfall manipulation treatment: Control, Dry, or Wet * Year – Year of
 decomposition period (YYYY) * Plot – Plot identifier (numeric label) *
 Annual precipitation (mm) – Rainfall during decomposition (mm) * Mass loss
 (%) – Percentage of initial litter mass lost (%) **File:
 Decomposition_Litter_transplantation.csv** * Period – Year(s) of
 decomposition experiment (e.g., 2002–2003) * Decomposition site – Site
 where litter was incubated * Litter source – Origin site of the litter
 material * Replicated litterbag – Litterbag replicate number (numeric) *
 Mass loss % – Percentage mass loss of each litterbag (%) --- ### **File:
 ANPP\_ANPP.csv** **Description**: Aboveground net primary production
 (ANPP) data collected across sites, treatments, plots, and years.
 **Variables** * Site – Site name (text) * Treatment – Rainfall
 manipulation treatment: Control, Wet, or Dry * Plot – Plot identifier
 (numeric) * Year – Year of sampling (YYYY) * Rain to sampling (mm) –
 Cumulative rainfall from previous fall until peak biomass sampling date
 (mm; rounded to integer) * ANPP (g/m²/yr) – Aboveground net primary
 production (grams per square meter per year) --- ## **Site Abbreviations**
 The following site abbreviations are used consistently across all
 datasets: | Abbreviation | Full Site Name | | :----------- |
 :----------------- | | Y | Ein Ya'akov | | M | Matta | | L | Lahav |
 | B | Be'er Sheva region | | Code | Description | | :--- |
 :---------------------------------- | | C | Control | | C-D | Control in
 2002, then dry treatment | | C-W | Control in 2002, then wet treatment | |
 D | Dry treatment | | W | Wet treatment | ## **Code and Software** All
 data files are provided in .csv (comma-separated values) format and are
 compatible with any text editor or statistical software such as R, Python
 (pandas), Excel, or SPSS.