ELECTRONIC SUPPLEMENTAL INFORMATION

Fig. S1 Effect sizes of nitrogen addition on aboveground plant nitrogen, leaf nitrogen, soil inorganic nitrogen, soil moisture and soil temperature. Error bars indicate effect sizes and 95% bootstrap confidence intervals. The dash lines are drawn at effect size = 0. The sample size for each variable is shown next to the bar.

Fig. S2 Effect sizes of nitrogen addition on species richness (SR), species diversity (SD), plant height (PH), graminoid height (PHgraminoid), sedge height (PHsedge), legume height (PHlegume) and forb height (PHforb) with standardization by nitrogen addition rate (that is, , where is nitrogen addition rate, g N m-2 y-1). Error bars indicate effect sizes and 95% bootstrap confidence intervals. The dash lines are drawn at effect size = 0. The sample size for each variable is shown next to the bar.

Fig. S3 Effect sizes of nitrogen addition on plant biomass (PB), aboveground biomass (AGB), belowground biomass (BGB), root/shoot ratio (R/S ratio), graminoid AGB (AGBgraminoid), sedge AGB (AGBsedge), legume AGB (AGBlegume) and forb AGB (AGBforb) with standardization by nitrogen addition rate (that is, , where is nitrogen addition rate, g N m-2 y-1). Error bars indicate effect sizes and 95% bootstrap confidence intervals. The dash lines are drawn at effect size = 0. The sample size for each variable is shown next to the bar.

Table S1 List of all the references in the meta-analysis

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