Taxa are classified according to whether they are native or alien to the Czech Republic. Following the definitions used in invasion ecology, native taxa are those that have evolved in the area of the Czech Republic or immigrated there without human assistance from the area where they had evolved. Alien taxa are those whose presence is a result of intentional or unintentional introduction by human activity and can be divided based on their residence time. The alien taxa are divided based on their residence time into archaeophytes and neophytes. Archaeophytes are taxa occurring in the wild that were introduced between the beginning of Neolithic agriculture and the year 1500, i.e. the beginning of intercontinental overseas trade after the discovery of the Americas. Neophytes are taxa occurring in the wild that were introduced after 1500 (see Richardson et al. 2000 for detailed definitions). Some taxa introduced in the Late Middle Ages or Early Modern Period, but with no exact information on the introduction date, were assigned to a joint category of Archaeophyte/neophyte. Additionally, some frequently cultivated taxa that are not known to have escaped from cultivation are listed as a separate category Cultivated. Category Lack of evidence of occurrence in the wild includes taxa for which spontaneous occurrence in the wild is doubtful. Taxa assigned to the category Absent in Czechia are not sufficiently supported by reliable records or occurred just once and disappeared.
The data included in the database follow the third edition of the Catalogue of alien plants of the Czech Republic (Pyšek et al. 2022 and references related to individual taxa therein).
Pyšek P., Sádlo J., Chrtek J. Jr., Chytrý M., Kaplan Z., Pergl J., Pokorná A., Axmanová I., Čuda J., Doležal J., Dřevojan P., Hejda M., Kočár P., Kortz A., Lososová Z., Lustyk P., Skálová H., Štajerová K., Večeřa M., Vítková M., Wild J. & Danihelka J. (2022) Catalogue of alien plants of the Czech Republic (3rd edition): species richness, status, distributions, habitats, regional invasion levels, introduction pathways and impacts. – Preslia 94: 447–577.
Richardson D. M., Pyšek P., Rejmánek M., Barbour M. G., Panetta F. D. & West C. J. (2000) Naturalization and invasion of alien plants: concepts and definitions. – Diversity and Distributions 6: 93–107.