Plant abundance (a) and species richness (b) as a function of invasion and plant group. Monocot species richness and plant abundance were significantly higher in soil from uninvaded sites than invaded sites (species richness: Kruskal-Wallis X12 = 13.4, p = 0.0002; plant abundance: Kruskal-Wallis X12 = 18.1, p < 0.0001), whereas species richness and abundance of dicots showed no difference. All data shown here are non-transformed.