beta diversity; cereals; root crops; Moravia

Comparison of weed vegetation of root crops and cereals in root-crop and cereal fields from Moravia (eastern Czech Republic) shows a distinct dichotomy between these two types of weed vegetation. There is no significant difference in total species richness and native species richness; however, cereal fields are richer in archaeophytes and root-crop fields are richer in neophytes. Beta-diversity of weed vegetation is higher in root-crop fields. Environmental factors explain significant part of variability in richness of both natives and aliens. While with increasing precipitation richness of native species increases, betadiversity of these species decreases. The opposite relationship between richness and beta diversity was found for archaeophytes, in both cereal and root-crop fields.