High population differentiation in the rock-dwelling land snail (Trochulus caelatus) endemic to the Swiss Jura Mountains

Abstract

Understanding patterns of genetic structure is fundamental for developing successful management programmes for isolated populations of threatened species. Trochulus caelatus is a small terrestrial snail endemic to calcareous rock cliffs in the Northwestern Swiss Jura Mountains. Eight microsatellite loci were used to assess the effect of habitat isolation on genetic population structure and gene flow among nine populations occurring on distinct cliffs. We found a high genetic differentiation among populations (mean F ST = 0.254) indicating that the populations are strongly isolated. Both allelic richness and effective population size were positively correlated with the size of the cliffs. Our findings support the hypothesis that T. caelatus survived on ice-free cliffs during the Pleistocene glacier advancements from the Alps. Due to the establishment of beech and pine forest under recent, temperate climate conditions, dispersal between cliffs is no longer possible for rock-dwelling snails such as T. caelatus. Our results provide basic data for developing a conservation action plan for this endangered gastropod species.

Strong genetic structure and signs of population bottlenecks in the land snailHumboldtiana durangoensisin the Sierra Madre Occidental of Western Mexico

“…The seven genetic groups of H. durangoensis analyzed here showed low levels of heterozygosity. These low values of genetic diversity have been reported in other groups of land snails and are associated with demographic and evolutionary factors such as population fragmentation, inbreeding, population bottlenecks, genetic drift, area effect, and the Wahlund effect (Armbruster, Koller, & Baur, ; Arnaud et al, ; Arnaud, Madec, Bellido, & Guiller, ; Buckley et al., ; Davison & Clarke, ; Emery et al., ; Erickson and Hadfield, ; Fiorentino et al., ; Guiller et al., ; Locher & Baur, ; Ozgo, ; Parent, Wu, Keays, & Crespi, ; Schilthuizen, ; Ursenbacher, Alvarez, Armbruster, & Baur, ).…”

Ongoing Speciation and Gene Flow between Taxonomically Challenging Trochulus Species Complex (Gastropoda: Hygromiidae)

“…caelatus [38] and T . oreinos [26,72], regional speciation with local persistence seems to be common within the genus Trochulus [13,16,27,71]. In general, the poor dispersal power of snails give rise to rather clear patterns of genetic differentiation related to distance; gene flow is limited [73].…”

“…The only study available to date on the delimitation of the Trochulus sericeus/hispidus complex is based on microsatellites [9]. Other studies were focused on the population genetic structure within species [10–13]. Moreover, recent investigations have demonstrated the limitations of DNA data, including barcoding attempts in highly diverse land snail species [14–16].…”

Reconstructing the evolutionary history of the radiation of the land snail genus Xerocrassa on Crete based on mitochondrial sequences and AFLP markers

“…It can be considered a paradigm for one of the causes of the high mitochondrial sequence diversity within land snail species discussed by Thomaz et al [36], namely long-term persistence of ancient polymorphisms resulting from the strongly subdivided population structure of land snails. The population structure of land snail species often consisting of many more or less isolated populations [37-40] that sometimes can reach high densities in favourable patches of habitat in conducive to the persistence of ancestral polymorphisms, because such a population structure increases the effective population size [41]. A more detailed analysis of the phylogeographic structure within X. mesostena is in preparation.…”