Fig. 4: Forest plots of effect sizes for different trait types under four species provenance scenarios.

a Trait means, expressed as log-response ratios (lnRR) between competition and control groups. b Trait variation, expressed as log-coefficients of variation ratio (lnCVR). The nonnative on nonnative scenario for chemical/physiological traits was excluded due to insufficient observations (K = 3). Effect sizes are shown as mean values ± 95% confidence intervals (CIs). K denotes the number of effect-size estimates derived from N = 346 studies (see Supplementary Data 1) and two-sided Tukey post hoc comparisons. Statistical details are provided in Supplementary Data 2. * P < 0.05, ** P < 0.01, *** P < 0.001.