Data from: Modest experimental warming reduces species diversity and biomass of arthropods in a Tibetan alpine meadow

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.