Composition and species richness of fallow plant communities with predominance of adventive species (Belaya River basin, Western Caucasus)

The effect of adventive dominants ( Erigeron annuus , Solidago canadensis , Ambrosia artemisiifolia , Asclepias syriaca , etc.) on the composition and species richness of fallow plant communities (Belaya River basin, Western Caucasus) are analyzed. The results show that (1) adventive dominants have light effects on the composition of fallow communities; (2) communities with more abundant adventive dominants are characterized by lower community species richness on the plots of 0.5 and 15 m 2 as a whole, and a lesser number of native species and higher number of adventive ones; and (3) communities with more abundant adventive dominants are characterized by a lower average frequency of native and adventive species on the plots of 0.5 m 2 . However, the relations between all these characteristics are poor.