This article reports changes in the segetal vegetation in the Borská nížina Lowland (Western Slovakia) over 50 years. The study was based on phytosociological relevés obtained by Krippelová in the years 1949-1955, as well as our own recent data from the years [2002][2003][2004][2005][2006]. Using ordination and statistical methods, structural and floristic changes to four associations recorded in the area in both time periods were evaluated: Veronicetum trilobae-triphyllidi, ConsolidoAnthemidetum austriacae, Echinochloo-Setarietum pumilae and Setario viridis-Erigeronetum canadensis. These plant communities are found in arable fields or young fallows. In some of these communities the proportion of invasive species, as well as archaeophytes and native species, has increased. Some agricultural practices (like fertilization and liming) support the spread of nitrophilous and calcareous species. Several ruderal species and herbicide-resistant species have expanded in the fields. In all studied associations the proportion of nutrient-demanding species has increased. Some rare and threatened species have declined or disappeared, but some threatened species that are missing from historical material are now present. However, the changes detected are not as substantial as expected based on data from other countries.

The paper presents data on the occurrence and secondary spreading of rare and threatened vascular plant species in railway habitats of Slovakia. We recorded 17 threatened vascular plant species and other 9 species that we considered to be rare in Slovakia. They grew at railway stations, mainly directly in the rail yard and also at the platforms or other similar facilities. Records of further 39 species were excerpted from literature sources. More native thermophilous species were represented among the recorded species as railway substrates provide suitable conditions for their growth. Also some archaeophytic segetal species were found quite frequent in the studied biotopes due to spreading of their seeds together with cereals transported by trains. Various habitats of railway transport facilities often provide suitable conditions for the secondary occurrence and further spreading not only of synanthropic or adventive, but also of rare and threatened plant species.

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