Warming enhances the negative impact of shrubs on community stability via reducing species asynchrony
Abstract
Numerous studies have demonstrated that climate warming and the presence of shrubs affect herbaceous plant community composition and function. However, how the temporal stability of herbaceous plant community biomass responds to combinations of warming and the presence of shrubs remains largely unexplored.
The effects and mechanisms of simulated warming and shrubs on the community stability were investigated in a 5-year field experiment in alpine grasslands.
Our results showed that warming alone or shrubs alone reduced community stability by decreasing species richness and temporal asynchrony. Additionally, warming alone or shrubs alone reduced community stability by decreasing community-weighted means of leaf dry matter content of species. We also found that the interaction of warming and shrubs had a cumulative negative effect on plant community stability by increasing species synchrony.
Synthesis: Our study suggests that continued global warming and shrub expansion may negatively affect the stability of natural grassland functions and services, and highlights the importance of temporal asynchrony and traits among species in moderating the effects of global change on ecosystem stability.
Dataset DOI: 10.5061/dryad.69p8cz9fp
Description of the data and file structure
Harvests were sorted by species, dried at 65°C for 72 hours, and then weighed for dry biomass. We describe biodiversity in terms of taxonomic, functional, and phylogenetic diversity. However, we did not predetermine which indicators were important; we analyzed them based on their correlation with community stability. Community weighted mean trait values (CWM) are based on plant height (CWMH), leaf area (CWM LA), specific leaf area (CWM SLA), and leaf dry matter content (CWM LDMC). Functional diversity was based on functional richness (FRic), functional evenness (FEve), functional divergence (FDiv), and functional dispersion (FDis), and phylogenetic diversity was determined based on mean nearest taxon distance (MNTD).
Files and variables
File: DATA.xlsx
Description:
Variables
sh: shrubs (P: shrubs present and R: shrubs removed)
wa: warming (N: no warming (ambient temperature) and W: warming)
C: Community stability (dimensionless)
Y: species asynchrony (dimensionless)
pr: species richness (dimensionless)
Community weighted mean trait values (CWM) are based on plant height (CWMH), leaf area (CWM LA), specific leaf area (CWM SLA), and leaf dry matter content (CWM LDMC).
CWM:Community weighted mean trait values (dimensionless)
H: plant height（cm）
LA: leaf area（cm2）
SLA: specific leaf area（cm2/g）
LDMC: leaf dry matter content (g/g)
FRic：functional richness (dimensionless)
FEve：functional evenness (dimensionless)
FDiv： functional divergence (dimensionless)
FDis：functional dispersion (dimensionless)
MNTD：mean nearest taxon distance (dimensionless)
Code/software
Statistical analysis was performed in R (version 4.0.5, R Development Core Team). All linear mixed-effects models were built using the lmer function from the ‘lme4’ package and the ‘piecewiseSEM’ package for constructing SEMs (Lefcheck, 2016). The figures were plotted using the ‘ggplot2’ package.