History of the penetration of anthropochorous mollusc species to western Ukraine

Abstract

Analysis of literary sources and materials of the malacological collection of the State Museum of Natural History of the National Academy of Sciences of Ukraine in Lviv revealed that at the end of the 19th century in western Ukraine could be present only some anthropochorous species of slugs, especially Limax maximus. Instead, mentions of a number of species not belonging to the indigenous malacofauna of Ukraine and its western region, made from the second half of the 19th to the middle of the 20th century, could most likely be based on the erroneous identification of other, native species. The process of intensive penetration into western Ukraine of alien species of land molluscs began, apparently, not earlier than the middle – second half of the 20th century and significantly accelerated at the turn of the 20th and 21st centuries. The latter could be due to both climate change, which facilitated adaptation to local climatic conditions for more thermophilic species, and the active import of seedlings of ornamental plants from other European countries. In particular, a dangerous pest from the complex Arion lusitanicus s.l. could enter the territory of Ukraine in this way. No less indicative are the relatively young colonies of Cepaea nemoralis, which are increasingly found in western Ukraine. Since the end of the 20th century, species of Caucasian origin and those that were previously observed only for the southern part of the country are increasingly registered in western Ukraine. Compared to the great taxonomic diversity of land anthropochorous molluscs and the widespread distribution of some of them, a relatively small number of freshwater species (up to 8), alien to this area, are still known in western Ukraine. For most of them, only a few finds are still known, made in the early 21st century. The exception is only one species (Physella acuta), which began to be mentioned for various areas in western Ukraine in the second half of the 20th century. Among the alien freshwater molluscs are a group of small species imported to Europe from other continents: New Zealand Potamopyrgus antipodarum, North American Menetus dilatatus, Physella heterostropha and possibly also Physa skinneri and Physella acuta. Representatives of the Dreissena genus came here from the Black Sea territories in the south of Ukraine.