Effect of habitat (A) [Forest versus Steppe] and disturbance (B (Disturbed [“Dist+”] versus Undisturbed [“Dist-”]) on the average individual biomass of native (“NTV”), naturalized (“NTZ”), and invasive (“INV”) plants in each plot as of July 2012. Individual plant biomass estimates were square root-transformed prior to analysis and responses are reported as least square means estimates ± SE. Values are derived solely from seed addition (SA+) plots to insure comparisons were conducted between individuals with similar durations of residence time within each plot. Post hoc multiple pairwise comparisons were conducted with the Tukey-Kramer method; different lowercase letters indicate significant differences at a Type I error = 0.05.