Nonmetric multidimensional plot of species abundance for (a) low-impacted sites and (b) urbanized sites.

Species labels match the codes provided in Table 2. Native species are shown in plain black font, and nonnative species are shown in gray italicized font. Sites sampled in the 1990s are denoted with black triangles and sites sampled in 2009 are denoted with gray circles. Sites located close together in plot space represent sites with more similar species assemblages. The convex hulls enclose sites sampled in each time period (1990s, 2009).