Vertigo lilljeborgi

Coufal, Radovan, Horsáková, Veronika, Peterka, Tomáš, Ryelandt, Julien, Skujienė, Grita & Horsák, Michal, 2024, Fig. 1 in Positive association between PTN polymorphisms and schizophrenia in Northeast Chinese Han population., Zoological Studies 63 (19), pp. 141-149 : 8-11

Vertigo lilljeborgi

Distribution

The main distribution area of Vertigo lilljeborgi spans over the boreal and arctic zones (see von Proschwitz 1993 2003; von Proschwitz et al. 2023). It has the most continuous occurrence in Fennoscandia when compared to the other two species and is also frequent in the northwestern parts of Great Britain and Ireland. Regarding these regions, the new records confirm the distribution documented by Kerney et al. (1983), with the exception of the southern half of Great Britain, where new sites have been discovered. The new personal records presented here show relatively rare and scattered occurrence in Lithuania, Latvia and Belarus as expected by Schenková and Horsák (2013a). Only one site is known from Estonia (data presented here); however, this region is underexplored and the species is likely to be more widespread there, as the records from adjacent countries suggest. The Baltic States region represents a transition zone between the frequent occurrence in Fennoscandia and the rare occurrence southwards, i.e., south of the area where the Scandinavian ice sheet occurred during the Last Glacial Maximum (LGM; Hughes et al. 2013). Poland and the Western Carpathians represent malacologically well explored regions with many ecologically suitable sites (e.g., Horsák and Hájek 2003; Schenková et al. 2012). Nevertheless, the species seems to be absent there, probably due to dispersal limitations ( Horsák et al. 2017). The main area of distribution in temperate Europe appears to be in the Bohemian Massif in Czechia and adjacent locations in Germany (data presented here; Schenková and Horsák 2013a; Horsák et al. 2017; Gabriel 2020; Čejka et al. 2020). In Czechia, most of the sites are severely damaged by human impact and the species occurs there in low abundances, likely living on extinction debt (pers. obs.; see Discussion in Horsák et al. 2017). Despite the extensive sampling and numerous ecologically suitable sites, V. lilljeborgi is very rare in the Alps. In Austria, only one site is known (data presented here) while there are five sites in the Swiss and French Alps ( Turner et al. 1998; Schenková and Horsák 2013a; Combrisson and Vuinée 2017). This supports its relictual status, as the species was likely influenced more by extinction than colonisation events ( Horsák et al. 2017). The known occurrence in France includes sites in the Massif Central and Western Alps ( Vrignaud 2012; Lecaplain 2013; Horsák et al. 2017), while older records from the French and Spanish Pyrenees mark the known southern edge of distribution ( van Regteren Altena 1934; von Proschwitz 2004). However, the minerotrophic fens of the Pyrenees and the Cantabrian Mountains are malacologically very poorly explored; therefore, the species may be more common there due to the presence of ecologically suitable sites ( Jiménez-Alfaro et al. 2014).

Ecology

According to the literature, the species inhabits mires, marshy lake margins with Carex vegetation and marshes with slightly acidic to neutral pH, low to intermediate alkalinity and a high water table ( Kerney et al. 1983; von Proschwitz 1993 2003; Schenková and Horsák 2013a; Nekola et al. 2018). Correspondingly, Horsák et al. (2017) showed data from relict sites of temperate Europe and southern Scandinavia indicating that the species inhabits predominantly strongly waterlogged slightly acidic to neutral sites with higher vegetation productivity. This is consistent with our results which showed that the species prefers the most waterlogged and base-poor sites of all analysed species. Accordingly, von Proschwitz (1993) showed that the species optimum in Sweden is at neutral sites with a pH value around 6.1. The response of abundance to summer temperature is unimodal; however, while Horsák et al. (2017) showed the peak around 14°C, our data show a peak around 17°C. This is surprising considering that our dataset contains more sites from colder Fennoscandia. In addition, in our extended dataset the species appears to tolerate a relatively wide range of winter temperature although it preferred rather colder sites. Together with similar results from Sweden ( von Proschwitz 2003), this suggests that the species is adapted for harsher conditions of continental climate. The ecological demands of northern and temperate populations were compared, but no significant differences were found (data not shown). On the contrary, Horsák et al. (2017), analysing the differences between the boreal and temperate occurrences in terms of vegetation composition, found the boreal sites to be wetter with less productive vegetation, while temperate European sites were more acidic and productive. As we did not have vegetation composition data for all sites, we could not perform similar analyses.