Fig. 1

Schematic illustration of the experimental design. a We created nine invasive communities differing in composition and diversity (species richness) by inoculating diluted soil suspensions (A: 10⁻¹, B: 10⁻³, and C: 10⁻⁶) extracted from three soils (E, M, and L, collected from salt marsh locations showing a significant difference in composition) in sterile soils obtained from an agricultural field. These were incubated for 28 days to allow for soil colonization and similar cell densities. At the end of this period, we generated nine soil communities that differed in species richness and composition but had similar cell densities. b Invasion experiments were performed by introducing nine invasive communities that had been adjusted to the same bacterial density into the soil collected from late-stage salt marsh and containing a natural, original resident community, soil L). The experiment was designed to consist of five destructive samplings on days 0, 5, 15, 30, and 60 after the invasion, using three replicates for each invasion treatment at each date. c Summary of the main analyses and respective measurements performed in this study