The level of invasion varies depending on the type of the habitat. The aim of this paper is to evaluate the level of floral invasion within the basin of the Ploučnice River in Northern Bohemia.
The values of the level of invasion were quantified for vegetation plots from the Czech National Phytosociological Database. Several maps documenting the level of invasion by alien plants were developed based on a quantitative assessment of the level of invasion of particular habitat types.
The levels of invasion were measured as a proportion of the species that are aliens and as the total cover by alien species, the same was done for archeophytes and neophytes separately. Mean levels of invasion were used for the habitats.