Exotic Species Occurrence in Remnant and Restored Eastern Prairie Ecosystems and their Relation to Native Species Richness, Evenness, and Functional Group Abundance

Abstract

Eight eastern U.S. prairie sites were sampled for exotic species abundance in relation to levels of native diversity; including species and functional richness, species evenness, and functional group similarity for the alpha (quadrat; 1m2; n = 508) and gamma (site; n = 8) scales. Spearman's rank co- efficient analyses found only a weak negative correlation (P < 0.001; rs =–0.14) with species richness and exotic abundance; and was nonsignificant for the other measures of diversity. Principal Components Analysis (PCA) indicated instead that exotic abundance was more correlated with higher soil parameter values among the sites. Both Lonicera japonica and Lespedeza cuneata represented 90% of the exotic cover from among the study sites.