An updated checklist of spiders of Czech republic

Milan Řezáč and Vlastimil Růžička

Czechia is one of the arachnologically best researched regions in Europe. So far, 906 spider species have been identified in this country (Buchar and Růžička 2002, Růžička and Buchar 2008, Kůrka et al. 2015, Řezáč et al. 2021). The Czech spider fauna lacks endemic species due to the glacial periods that have occurred. The oldest components of Czech spider fauna are glacial relics that survived in alpine and peat bog habitats and boreal relics that survived in steppe habitats. The Czech spider fauna is thus mainly composed of species with a Palaearctic distribution. Only a very small proportion of the species are endemic to Central Europe; in particular, few Carpathian endemics occur in the mountains in eastern Moravia, and few Pannonian endemics occur in the lowlands in southern Moravia. Many species of natural habitats are disappearing, and 58% of the Czech spider fauna are red listed (Řezáč et al. 2015).

To date, approximately fifty species found in Czechia are considered allochthonous. The majority of them are restricted to buildings. Moreover, some species have colonized the surroundings of buildings. Only a small fraction of spider species introduced to Czechia have invaded natural habitats. In addition to these species introduced by humans, there are also several cases of species that recently expanded their distribution from the south to Czechia, perhaps due to climate warming. According to these criteria we classify the Czech non-native spider species into the following five cathegories. Species identity is based on Nentwig et al. (2023). The nomenclature follows the World Spider Catalog (2023).

References

Původnost druhů

Thermophilic expanding species (E)

History: Absent from the region in the past – new records even from arachnologically well researched sites in the past.
Habitat: Often newly created habitats such as mining areas.
Distribution: Known to occur south of Central Europe, usually absent north of Central Europe.

Species introduced to buildings – expanding (I-B-E)

History: Newly introduced by humans and expanding their range.
Habitat: All kinds of heated buildings, absent in nature.
Distribution: Mainly subtropical regions.

Species introduced to buildings – non-expanding (I-B-N)

History: Newly introduced by humans.
Habitat: Large heated buildings with complex synanthropic habitats, such as large greenhouses with high air humidity and rich prey resources, absent in nature.
Distribution: Mainly tropical regions.

Species introduced to natural habitats – invasive (I-N-I)

History: Introduced by humans and expanding their range.
Habitat: Variety of natural habitats, often disturbed.
Distribution: Native on other continents, often North America.

Species introduced to natural habitats – non-invasive (I-N-N)

History: Newly introduced by humans.
Habitat: Disturbed habitats in nature.
Distribution: Sites of introduction isolated from the continuous distribution area of the species.

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Species introduced to buildings – expanding

History: Newly introduced by humans and expanding their range.
Habitat: All kinds of heated buildings, absent in nature.
Distribution: Mainly subtropical regions.