Beta-diversity, Czech Republic, cereals, root crop

Changes in weed species richness and beta-diversity are partly attributable to different types and intensity of disturbance and partly to broad-scale variation in environmental conditions. We compiled a data set of 434 vegetation plots of weed vegetation in root crop and cereal fields in Moravia (eastern Czech Republic) to compare the effects of environmental conditions and different disturbance regimes on species richness and beta-diversity in these two arable field habitats. To detect changes in species richness we related the variation in species richness to individual environmental conditions. To assess differences in beta-diversity between the vegetation of cereal and root crop fields we used Whittaker?s measure of beta-diversity. The relative importance of each environmental variable for the variation in species composition was evaluated using canonical correspondence analysis. All analyses were done for all vascular plant species and separately for native species, archaeophytes, and neophytes.