The list has been compared with the family catalogues available on this website. The names of families and taxa in the list have been updated according to these catalogues. The names were taken as of 24 February 2026.

The origin status was taken from the DAISIE database. Taxa displayed that were not listed in the DAISIE database at the time the list was prepared were added from other sources, if the information was known.

Year of first occurrence of the taxon in the Czech Republic, if known.

The field value can take one of the following values:

• Information about the documented first occurrence of the taxon (e.g. 2000). If the information is not known, but similar information is known for Europe, i.e. the first occurrence of the taxon in Europe, the value entered in this field is, for example, > 1980 (= the first occurrence of the taxon in Europe is listed in 1980) or < 1885 (= the first occurrence of the taxon in Europe is recorded before 1885).
• If an asterisk (*) is placed before the year, it means that the year refers to the first observation (which is usually not the first occurrence) or to the first publication on the occurrence of the species.
• A question mark (?) means that it was not possible to determine the date of the first occurrence of the species in the Czech Republic from the available sources.

The place from which the species was introduced to the Czech Republic.

In addition to the basic regions listed above, abbreviations are added to further specify the region:

The manner in which a non-native species entered a new area of distribution.

Depending on the duration and nature of their occurrence, alien species are divided into the following categories:

• Eusynanthropic species – S, which survive only for a short time after introduction and reproduce only inside buildings, greenhouses and other heated structures, gradually disappearing or being destroyed (as indicated by the letter in brackets), or forming long-term populations in such places and possibly being dispersed by humans (partly spontaneously during the warm season); exceptionally, some of these species may form short-term populations in open spaces – SC.

• Accidentally non-native species – C, which, after escaping or being released into the open, form only short-term populations and then disappear again (this group does not include individuals that have escaped from captivity or individual captures of introduced animals that did not reproduce further).

• Naturalised, non-invasive species – N, which form long-term populations in the external environment, colonise suitable habitats at the site of introduction, do not spread, or if they do, only in the immediate vicinity of this site.

• Naturalised, post-invasive species (Pyšek et al., 2002) colonised this area in the past and have been known since the beginning of their study as fully naturalised, with more or less no changes in their distribution – *N, e.g. Aceria tristriata, A. erinea, Caloptilia roscipennella, Chromaphis juglandicola and Panaphis juglandis (all trophically linked to Juglans regia). These species evidently invaded Central Europe before 1900, and there is no way to determine whether they were dispersed with the host plant, followed it immediately, or invaded the area with a certain time lag. It appears that the invasions of many species occurred long after their host species had been introduced, which also suggests that in several cases, the dispersal of the host may not have been the only factor that initiated the invasion. For example, the invasion of the moth of the genus Gracillariidae, Phyllonorycter platani, did not occur until the 20th century (Šefrová, 2001), and the invasion of the bug Lygaeidae, Arocatus longiceps, did not occur until the end of the century (Stehlík & Hradil, 2000), although plane trees (Platanus spp.), their host species, had been planted in Central Europe for about 200 years. These species are considered invasive and are classified in another group. A somewhat special group consists of several species of fish and birds that do not reproduce naturally but are often kept in open spaces, sometimes in large numbers, and can thus significantly influence processes in semi-natural and natural ecosystems, as well as their biodiversity – M.

• Invasive species – I, representing that part of naturalised species that does not remain in the place of introduction but disperses from it and colonises areas of varying sizes. The speed of such animal invasions is sometimes significantly higher than that of plant species (see Richardson et al., 2000) and usually reaches kilometres or even hundreds of kilometres per year. For example, the current invasion of Cameraria ohridella in Europe is spreading at a rate of approximately 50 km per year (Šefrová, 2003).

The status of non-native species and their occurrence is clearly shown in the overview table:

The occurrence of naturalised species is limited to urban habitats (U) to which they are bound in terms of climate, environmental structure or food (e.g. they feed on ornamental plants, domestic animals and other synanthropic species), or spread across the landscape by occupying man-made habitats (agricultural crops, purpose-built vegetation, artificial water habitats, ruderal areas) (R), or penetrate semi-natural and natural communities (A). Animal and some plant parasites are closely linked to their hosts; their occurrence depends more on the occurrence of the host than on the nature of the habitat (H).

The second letter added to the code specifies the habitat:

The main entry in this field characterises the main type of nutrition (trophic strategy) of the species in question.

The second letter in brackets specifies the potential impact, i.e. the possible economic or ecological significance of the species: