Plasticity indices (PI_v) for invasive and non-invasive species.

Trait abbreviations as in Table 1. Test statistics (t) and p-values (p) are from Student's t-test for unequal variances; p-values in boldface are <.05. The bottom three rows represent mean values for combined indices with several traits' plasticity indices averaged together by species (see also Figure 3). No plasticity indices for individual traits were significantly different between invasive and non-invasive groups after Benjamini-Hochberg correction for 17 trait comparisons, nor were grouped indices significantly different after correction for three comparisons. Means, standard errors, and test statistics were calculated using the PIv, which represents the absolute value of the change in trait value between N treatments, but a second index, the RTR, was used to determine the directionality of the response, which is indicated to the right of each PIv column for individual traits. “Increase” means that all species in the group increased the trait value in response to increased N; “decrease” means that all species in the group decreased the trait value; and “mixed” means that at least one increase and one decrease were observed in the species group. Table S2 in the Supplementary Information shows RTR values for all traits and all species.