Data for: Environmental filtering drives biodiversity‒spatial stability relationships in a large temperate forest region

The assumption that greater biodiversity enhances ecosystem stability,
commonly known as "portfolio effect", has attracted considerable
research attention. However, the potential portfolio effects on spatial
stability (the similarity of ecosystem functioning among forest
communities) are still poorly examined especially at different spatial
scales and under varying environmental stress conditions. Accordingly,
this study investigates the biodiversity-spatial stability relationship
among regional communities across different spatial scales and
environmental conditions in a temperate forest region. We define spatial
stability as the invariability of the productivity of woody plants among
plots within a regional community. To test spatial stability, the N
closest plots to a given plot were aggregated to form regional communities
representing different spatial scales. Structural equation modeling was
used to evaluate how biodiversity (including taxonomic (TD) and
phylogenetic diversity (PD)) increases spatial stability via species
asynchrony and/or population stability across spatial scales. Hierarchical
Bayesian modeling was used to evaluate the environmental dependence of the
portfolio effects on spatial stability. TD and PD both increased spatial
stability by increasing asynchrony, but decreased population stability.
The portfolio effect of TD on spatial stability became stronger and
reached saturation at the intermediate scale and then decreased as
regional communities became larger. The portfolio effects of TD were
weaker under the stressful conditions of drought, high precipitation
seasonality and high elevation but unchanged across temperature
seasonality and human disturbance. PD showed no discernable effect on
spatial stability and did not change across spatial scale and
environmental condition. Our results suggest that the positive effect of
biodiversity on species asynchrony overcomes the negative biodiversity
effect on population stability to buffer the spatial change in
productivity in diverse communities. Future research on the
biodiversity–spatial stability relationship may thus benefit from
incorporating different spatial scales and environmental conditions into
the analysis.