Data from: Herbivore species and patch heterogeneity modulate grazing-induced shifts in soil nematode trophic structure and energy flux
Data files
Oct 12, 2025 version files 52.05 KB
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Data_FE_FE-2025-00968.R1.xlsx
45.92 KB
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README.md
6.13 KB
Oct 31, 2025 version files 49.70 KB
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Data_FE_FE-2025-00968.R1.xlsx
43.57 KB
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README.md
6.13 KB
Abstract
Grazing by large herbivores is a critical factor in shaping grassland biodiversity and ecosystem functioning worldwide; however, its consequences for soil communities remain poorly understood. This gap is important because soil food webs underpin ecosystem processes and may respond differently to grazing depending on herbivore identity and local heterogeneity (i.e., patchiness). Here, a four-year field experiment was conducted to investigate the influence of cattle and sheep grazing on soil nematode communities in a grassland featuring a mosaic of degraded high-salinity and undegraded low-salinity patches. We focus on nematode communities because nematode-based indices offer key insights into the structure of the soil food web and overall soil health. In the absence of grazing, degraded patches exhibited a more simplified soil food web structure, indicated by reduced nematode diversity, maturity index, and structure index, but higher nematode biomass and energy flux compared to undegraded patches. However, sheep grazing reduced total nematode biomass and energy flux in degraded patches, while cattle grazing decreased the biomass of higher trophic levels (i.e., omnivores and predators), the energy flux from lower to higher trophic levels, and flow uniformity in undegraded patches. These effects resulted from declines in the abundance of large-bodied nematodes, primarily limited by soil pore space and soil microbial biomass. Collectively, our findings demonstrate that livestock grazing can exacerbate soil degradation by inhibiting soil fauna communities, but the outcomes are patch- and herbivore-specific. By combining nematode structural and functional indices, our study advances understanding of how herbivore identity interacts with fine-scale grassland heterogeneity to regulate soil food webs. This framework provides a new pathway for linking grazing management to soil health, offering a scientific basis for adaptive policies that balance production goals with sustainable grassland restoration under environmental change.
Dataset DOI: 10.5061/dryad.7pvmcvf6q
Description of the data and file structure
Soil samples were collected at the end of the 2020 growing season from grazed grassland paddocks comprising high- and low-salinity patches, with two replicates in high-salinity patches and four in low-salinity patches, reflecting their proportional area coverage. Composite soil cores (0–10 cm depth) were obtained and divided for different analyses. Fresh subsamples were used to extract nematodes via modified Baermann funnels and to determine soil water content. Other subsamples were analyzed for microbial biomass carbon and nitrogen, available nitrogen, and soil physicochemical properties, including pH, electrical conductivity, total organic carbon, total nitrogen, and total phosphorus. Nematodes were identified to genus or family level under a compound microscope, and their body sizes were measured to estimate biomass. Multiple abundance-based and size-based indices were then calculated to characterize soil food-web structure, ecosystem functioning, and nematode energy fluxes across trophic groups.
Files and variables
File: Data_FE_FE-2025-00968.R1.xlsx
Description: Data columns include blocks, grazing treatments, patch types, and plot information, as well as the abundance, community-weighted mean body weight, and biomass of total nematodes and each trophic group. The data also contains nematode abundance-based structural indices, size-based energy flux metrics, and associated soil physicochemical properties.
Blocks: 1, 2, 3
- Grazing: Ungrazing, Cattle grazing, Sheep grazing
- Patch: Low salinity patches, High salinity patches
- Replicates: 1–2 replicates in low salinity patches, 1–4 replicates in high salinity patches
- Total nematode abundance (indiv. / 100g dry soil): Abundance of total nematodes
- Abundance_He (indiv. / 100g dry soil): Abundance of herbivores
- Abundance_Ba (indiv. / 100g dry soil): Abundance of bacterivores
- Abundance_Fu (indiv./100g dry soil): Abundance of fungivores
- Abundance_OP (indiv./100g dry soil): Abundance of omnivores-predators
- Total nematode cwmW (μg): Community weighted mean weight of total nematodes
- cwmW_He (μg): Community weighted mean weight of herbivores
- cwmW_Ba (μg): Community weighted mean weight of bacterivores
- cwmW_Fu (μg): Community weighted mean weight of fungivores
- cwmW_OP (μg): Community weighted mean weight of omnivores-predators
- Total nematode biomass (μg/100g dry soil): Biomass of total nematodes
- Biomass_He (μg/100g dry soil): Biomass of herbivores
- Biomass_Ba (μg/100g dry soil): Biomass of bacterivores
- Biomass_Fu (μg/100g dry soil): Biomass of fungivores
- Biomass_OP (μg/100g dry soil): Biomass of omnivores-predators
- Nematode Shannon-Wiener index
- Nematode trophic diversity
- Plant parasite index
- Maturity index
- Maturity index 2–5
- Sigma maturity index
- Basal index
- Enrichment index
- Structure index
- Nematode channel ratio
- Relative abundance_He (%): Relative abundance of herbivores
- Relative_abundance_Ba (%): Relative abundance of bacterivores
- Relative_abundance_Fu (%): Relative abundance of fungivores
- Relative_abundance_OP (%): Relative abundance of omnivores-predators
- Flux_Resource_He (μg C / 100g dry soil / day): Energy flux from resource to herbivores
- Flux_Resource_Ba (μg C / 100g dry soil / day): Energy flux from resource to bacterivores
- Flux_Resource_Fu (μg C / 100g dry soil / day): Energy flux from resource to fungivores
- Flux_He_OP (μg C / 100g dry soil / day): Energy flux from herbivores to omnivores-predators
- Flux_Ba_OP (μg C / 100g dry soil / day): Energy flux from bacterivores to omnivores-predators
- Flux_Fu_OP (μg C / 100g dry soil / day): Energy flux from fungivores to omnivores-predators
- Total energy flux (μg C / 100g dry soil / day)
- Flow uniformity
- Microbial biomass carbon (mg/kg)
- Microbial biomass nitrogen (mg/kg)
- Soil water content (%)
- pH
- Electrical conductivity (μS/cm)
- Soil bulk density (g/cm³)
- Soil total organic carbon (g/kg)
- Soil total nitrogen (g/kg)
- Soil total phosphorus (g/kg)
- Soil carbon_nitrogen ratio
- Soil carbon_phosphorus ratio
- Soil nitrogen_phosphorus ratio
- Soil NH4-N (mg/kg): Soil NH₄⁺-N content
- Soil NO3-N (mg/kg): Soil NO₃⁻-N content
Code/software
All data analyses were conducted using R software (version 4.4.0; R Core Team, 2024), which is freely available under an open-source license (https://www.r-project.org/). The workflow involved fitting mixed-effect linear models to evaluate the effects of grazing treatments, patch types, and their interaction on nematode community metrics and soil properties. Fixed effects included grazing treatment, patch type, and their interaction, while nested random effects accounted for sample replication within blocks. Tukey’s post hoc tests were applied to determine pairwise differences. Community composition was analyzed using nonmetric multidimensional scaling (NMDS) based on Bray–Curtis distances and PERMANOVA (adonis2) with PERMDISP2 to test for multivariate homogeneity of dispersions. Redundancy analysis (RDA) with forward selection and permutation tests (999 runs) identified key environmental drivers. Linear regression analyses were further used to assess relationships between nematode energy flux, flow uniformity, and environmental factors. The main R packages used include vegan, lme4, multcomp, ggplot2, and car.
Access information
Other publicly accessible locations of the data:
- The dataset described here is original and not deposited elsewhere. No other publicly accessible locations exist.
Data was derived from the following sources:
- All data were generated from field experiments and laboratory analyses conducted by the authors. No data were derived from previously published or publicly available datasets.
Changes after Oct 12, 2025:
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The first row (header line) of the data file has been corrected.
Specifically:Biomass_He was changed to Biomass_Ba
Biomass_Ba was changed to Biomass_Fu
Biomass_Fu was changed to Biomass_He
No other data or variable values were modified.
