Helix albescens Rossmässler, 1839

Gural-Sverlova, N. V. & Gural, R. I., 2024, Alien Mollusks Of Crimean Origin In Other Parts Of Ukraine: Present Distribution And Chronology Of Its Discovery, Zoodiversity 58 (5), pp. 369-380 : 376-378

Helix albescens Rossmässler, 1839

H. albescens is now widespread in southern Ukraine, including Crimea, and occurs also in some areas of the Caucasian region. Results from a recent genetic study indicate that this species is most likely of Crimean origin ( Korábek et al., 2023), similar to the four land snail species described above. However, unlike them, the Caucasus may also be part of the natural range of H. albescens . According to Korábek et al. (2023), “it is possible that H. albescens was present in the Caucasus already before the Last Glacial”. At the same time, “the extent of the native distribution of H. albescens on the East European Plain is unclear… Thus, H. albescens is now spreading northwards and it is possible that much of its distribution in the East European Plain is the result of recent expansion, possibly largely human-assisted”.

Similar to B. cylindrica (see above), the first known records of H. albescens in Ukraine outside Crimea were described at the beginning of the 20th century ( table 1). Lindholm (1908) mentions several specimens of Helicogena obtusata (Rossmässler, 1837) , now a synonym for H. albescens , collected in Odesa and on the Dnipro River bank near Havrylivka village in the present Beryslav District of the Kherson Region. In the middle of the 20th century, this species was also mentioned for the administrative centres of the Mykolaiv and Kherson Regions, as well as for Melitopol in the south of the Zaporizhzhia Region ( Likharev & Rammelmeyer, 1952). The same set of settlements (Odesa, Mykolaiv, Kherson, Melitopol) is repeated several decades later by Schileyko (1978). At the end of the 20th century, H. albescens was recorded both in anthropogenic biotopes of Mykolaiv and its environs, and in shrub thickets, sometimes in open meadow sites of the coastal areas of the Mykolaiv Region ( Kramarenko & Sverlova, 2001).

The earliest sample of H. albescens from eastern Ukraine, stored at SMNHL ( Gural-Sverlova & Gural, 2020 a), was collected in 1987 in one of the city parks of Donetsk. We did not find any literary references to earlier records of H. albescens in this part of Ukraine, however, focused study of land mollusks began here also relatively recently ( Gural-Sverlova et al., 2012). Apparently, the most interesting finds of H. albescens were made at the beginning of the 21st century in floodplain forests in the south of the Lugansk Region (Balashov, 2013). H. albescens was recorded there twice together with a relict species of Caucasian origin, Elia novorossica (Retowski, 1888) . In addition to land mollusks, the Donetsk Upland could be a refugium for a number of invertebrate and plant species ( Gural-Sverlova & Martynov, 2009).

While the nature of the range of H. albescens (native or recently expanded as a result of human activity) in southern Ukraine is difficult to determine, the lately noted movement of this species to the north ( table 1), up to the Kyiv, Poltava and Kharkiv Regions ( fig. 3 ) is clearly caused by relativelly recent introductions, intentional or accidental. In administrative regions not bordering the Black or Azov Seas, H. albescens is more often observed in regional centres (Dnipro, Kyiv, Poltava, Kropyvnytskyi) and other large settlements (for example, Kryvyi Rih in the Dnipropetrovsk Region). One of the northernmost known records, made in Kyiv in 2006, was described in a separate publication ( Balashov & Vasyliuk, 2007).

In general, at least single species of land mollusks of Crimean origin, analysed in this paper, have now been reliably registered in more than half of the administrative regions of Ukraine ( fig. 4 , table 2). Predictable, a larger number of such species were recorded in the south of Ukraine, especially in the Odesa, Kherson and Zaporizhzhia Regions ( fig. 4 ). Outside the steppe zone of Ukraine, the Kyiv Region is in the lead, which is caused by the large capital city as well as the intensity of malacological research and a larger number of amateur naturalists posting their observations in citizen science databases .

Despite the fact that three of the analysed species of land mollusks ( B. cylindrica , M. fruticola , H. albescens ) are currently quite widespread in Ukraine, their penetration into many administrative regions happened relatively recently. This may be indirectly evidenced by the dates of their first records ( tables 1, 2). The only exceptions are such southern regions, close to the Crimean peninsula, as Odesa, Kherson and Zaporizhzhia ones (table 2), where single records of B. cylindrica and H. albescens were known already at the beginning of the 20th century. It is significant that these finds were made in a port city (Odesa) or along the Dnipro River, which was also an important transport route. The colonization the coastal areas of southern Ukraine by some species of Crimean origin (as a result of natural expansion of species ranges or introductions) then increased the likelihood of their further transportation by people to more distant territories.

Сonclusions

Two of the five analysed species of land mollusks of Crimean origin ( B. cylindrica , M. fruticola ) are now also known in all parts of Ukraine outside Crimea, at least from single records in recent years. B. cylindrica occurs in some settlements not only in the north of Ukraine, but also much further north, in Minsk, Belarus. A third species, H. albescens , is also gradually expanding its range in Ukraine, although it has not yet been discovered in the west of the country. B. bidens has so far been registered in four localities of Odesa, Kherson and Zaporizhzhia Regions, one of which is mentioned for the first time in this article. For M. gracilicosta , endemic to the mountainous Crimea, a single introduction into Odesa has been described.

The data systematised in the article can become the basis for monitoring the further spread of the analysed species of land mollusks in different parts of Ukraine. In addition to mollusks of Crimean origin, Crimea could be a source of introduction of some other species, autochthonous or alien to the Crimean peninsula itself, to other administrative regions of Ukraine. These will be reviewed in a separate publication.

Acknowledgments

The authors are grateful to all the persons who, at different times, handed over the land mollusks they collected in different regions of Ukraine to the Malacological Collection or to the Malacological Laboratory of the SMNHL for identification. We are particularly grateful to Andrii Shklyaruk (Odesa), Serhii Kramarenko (Mykolaiv National Agrarian University ), Volodymyr Martynov (Donetsk National University ), Viktor Busel ( Velykyi Luh National Nature Park , Zaporizhzhya Region), and Maxim Gensytskyi ( Melitopol State Pedagogical University ) for the valuable data they provided for our publication .

Figures

Fig. 3. Known records of Helix albescens in Ukraine outside Crimea; symbols are similar to fig. 1.

Fig. 4. Number of analysed species recorded in different administrative regions of Ukraine outside Crimea.