Extended Data Fig. 2: Effects of experimental treatments on soil and plant variables by linear mixed-effects models (LMMs).
From: Reduction of microbial diversity in grassland soil is driven by long-term climate warming
a, Soil temperature; b, Soil moisture; c, Soil pH; d, Soil NO3−N; e, Soil NH4-N; f, Total plant biomass; and g, Plant richness. Data are presented as mean values ± standard errors of the estimated effect sizes. Statistical significance is based on Wald type II χ² tests (n = 360 independent soil samples). Significant effects are denoted by asterisks: *** P < 0.001, ** P < 0.01, * P < 0.05. W: Warming; P: Precipitation level; C: Clipping. Since the precipitation level is considered as a continuous variable in the LMM (0.5 for half precipitation, 1 for normal and 2 for double precipitation), only one regression coefficient of precipitation treatment would be derived by the LMM. The effect size of half precipitation (as compared to ambient precipitation) can be derived by multiplying the regression coefficient by −0.5, while the effect size of double precipitation (as compared to ambient precipitation) can be derived by multiplying the regression coefficient by 1.
