Fig. 6. (A) Emergent vascular plant (macrophyte) biomass (mean ± 1 SE) at wetlands in each of the four study sites, and (B) percentage of invasive macrophyte species (mean ± 1 SE) at wetlands in each of the four study sites. Student t-tests were performed on pooled data from sites with either small-town or suburban typologies, i.e., sites 3.1 and 3.4 together vs. sites 3.7 and 4.2 together, to test H₀ of no difference between typological means. The dark bars indicate that typological differences between watersheds with small-town typologies and those with suburban typologies were significant. Light bars indicate that the difference between typological means was not significant.