DOI: 10.5061/dryad.p2ngf1w33
title: Data from: Modest experimental warming reduces species diversity and biomass of arthropods in a Tibetan alpine meadow

description: Climate warming is expected to contribute to the decline of arthropod
 species diversity and biomass around the world. However, direct
 experimental evidence is lacking. Here, we report on a field experiment
 documenting arthropod species diversity and biomass responses to passive
 simulated warming for six consecutive years in an alpine meadow on the
 Tibetan Plateau. The field warming experiment consisted of six large
 open-top chambers (15 m × 15 m × 2.5 m), with three chambers warmed and
 three non-warmed, resulting in mean temperature differences of 0.18°C and
 0.57°C in the growing season and the non-growing season, respectively.
 Warming decreased arthropod species diversity by 39% and arthropod biomass
 by 18% during the experiment. Specifically, the richness of large-bodied
 species decreased, while small-bodied species were not significantly
 affected. Moreover, the abundance of small-bodied species increased, but
 that of large-bodied ones decreased, resulting in decreases in community
 size spectrum and community-weighted mean body size under warming. Results
 of the structural equation model suggest that the decreases in arthropod
 species diversity (represented by species richness and community size
 spectrum) and biomass were primarily caused by a warming-induced shift
 from forb- to graminoid-dominated plant communities, which could be
 attributed to a warming-induced decrease in soil moisture. Moreover, the
 warming effect on arthropod species diversity and biomass was more
 pronounced in the late years of the experiment, which could be partly
 related to the increase in mean annual temperature over the course of the
 experiment and the progressing shift in plant community species
 composition over time. Our study provides unique experimental evidence
 that even very modest warming may result in declines in both species
 diversity and biomass of arthropods through cascades of indirect effects,
 and identifies important mechanisms underlying biodiversity loss.
description: # Modest experimental warming reduces species diversity and biomass of
 arthropods in a Tibetan alpine meadow Dataset DOI:
 [10.5061/dryad.p2ngf1w33](10.5061/dryad.p2ngf1w33) ## Description of the
 data and file structure **Dataset Overview:** This dataset contains the
 data used to generate figures in Hu et al. (2025), testing the hypothesis
 that experimental warming would decrease the species diversity and biomass
 of arthropods. Sweep nets (standard equipment with 38 cm diameter) were
 used to survey arthropod communities in all six chambers from June to
 August each year from 2017 to 2022 (seven surveys annually). All captured
 arthropods were manually sorted and identified based on morphological
 traits, recorded, and then released back into the chambers they were taken
 from. Samples of unidentified species were collected and identified using
 DNA barcoding. To assess the warming effect on arthropod biomass, a
 minimum of three individuals (at least one individual from each chamber;
 except for very rare species such as Ceraeochrysa sp. and Tetanocera sp.,
 for which two individuals were collected) were collected for each
 arthropod species in 2020, dried, and weighed to determine dry body mass.
 In addition, sixteen of the herbivorous species experienced significant
 changes in abundance due to warming were recorded. The feeding preference
 for graminoids for each herbivore species and for each chamber as the sum
 of the relative frequency of the graminoid species in its diet. We
 investigated whether the impact of warming on species abundance was
 influenced by species body size. Initially, we developed generalized
 linear mixed models with warming as a fixed effect and year and chamber
 identity as random effects to assess the warming effect on the abundance
 for each species. Subsequently, we used the slope of GLMMs (*ß*) for
 species that exhibited significant changes in abundance in response to
 warming to indicate the direction and extent of warming effects on species
 abundance. Plant species composition was investigated using a quadrat
 sampling method. twenty sampling quadrats were randomly selected in each
 chamber each year from 2017 to 2022. plants were clipped at the ground
 level and classified into graminoids (i.e. Poaceae and Cyperaceae species)
 and non-graminoids (all the remaining species, including forbs and legume
 species). The air temperature, vapor pressure deficit, soil moisture at 5
 cm depth, daily precipitation were measured. **Description of the data and
 file structure** This repository contains all data used in Hu et al.
 (2025). Raw data were processed using R software for statistical analyses.
 File names correspond to the plots for major figures in the manuscript,
 categorized below based on arthropod community, plant community, and
 meteorological conditions, with summary statistics provided for key
 figures. **arthropod_community.csv** This file contains the arthropods
 abundance of each chamber from 2017 to 2022. The species names were showed
 in the “species_information.csv”. Number of columns: 154 Number of rows:
 253 **arthropod_body_mass.csv** This file contains the arthropods body
 mass each chamber in 2020. The species names were showed in the
 “species_information.csv”. Number of columns: 4 Number of rows: 1762
 **abundance_significant_changes.csv** This file contains the slope of
 GLMMs (*estimate*) for species that exhibited significant changes in
 abundance in response to warming. x2 means chi-square value. P means P
 value. Number of columns: 5 Number of rows: 42
 **herbivore_feeding_preference.csv** This file contains the feeding
 preference for graminoids for each herbivore species. The species names
 were shown in the “species_information.csv”. Number of columns:6 Number of
 rows: 84 **species_information.csv** This file contains the observed
 species identity, average body mass, Latin names and COI sequences. Number
 of columns:4 Number of rows: 152 **plant_community.csv** This file
 contains the plant aboveground biomass and relative biomass of graminoids.
 The unit of plant aboveground biomass g per square meter. Number of
 columns: 7 Number of rows: 577 **air_temperature.csv** This file contains
 the air temperature at 30 cm aboveground in both non-warmed and warmed
 chambers from 2017 to 2022. The unit of temperature is degrees Celsius.
 Number of columns: 3 Number of rows: 4380 **VPD.csv** This file contains
 the vapor pressure deficit both in non-warmed and warmed chambers from
 2018 to 2022. Number of columns: 3 Number of rows: 64718
 **soil_moisture.csv** This file contains the soil volumetric water content
 at 5 cm depth both in non-warmed and warmed chambers, in August from 2017
 to 2022. Number of columns: 3 Number of rows: 7441 **precipitation.csv**
 This file contains the daily precipitation in the study site from 2017 to
 2022. Number of columns: 2 Number of rows: 2192 **glmm_sem_data.csv** This
 file contains the processing data used for (generalized) linear mixed
 models and structural equation modelling. The meaning of abbreviated
 column names: days_above_0: The days above 0°C each year
 min_soil_moisture: The minimum soil moisture at 5 cm depth in August
 cwm_size: The arthropod community weighted mean of body mass CSS:
 community size spectrum abundance_large_2: the abundance of arthropods
 with body mass greater than 2 mg abundance_less_2: the abundance of
 arthropods with body mass less than 2 mg richness_large_2: the species
 richness of arthropods whose body mass is greater than 2 mg
 richness_less_2: the species richness of arthropods whose body mass is
 less than 2 mg SR_0_25: The species richness of arthropods with body mass
 less than 0.925 mg (25% quantile) SR_25_50: The species richness of
 arthropods with body mass from 0.925 mg to 2.218 mg (50% quantile)
 SR_50_75: The species richness of arthropods with body mass 2.218 mg to
 4.635 mg (75% quantile) SR_75_100: The species richness of arthropods with
 body mass greater than 4.635 mg (100% quantile) abundance_0_25: The
 abundance of arthropods with body mass less than 0.925 mg (25% quantile)
 abundance_25_50: The abundance of arthropods with body mass from 0.925 mg
 to 2.218 mg (50% quantile) abundance_50_75: The abundance of arthropods
 with body mass 2.218 mg to 4.635 mg (75% quantile) abundance_75_100: The
 abundance of arthropods with body mass greater than 4.635 mg (100%
 quantile)
  **experimental_warming_decrease_arthropod_diversity_biomass.xlsx**: This
 Excel workbook contains all data sheets listed above combined and
 separated by tab.