Communities of terrestrial mollusks on chalky slopes in the forest-steppe zone (the Middle Volga river region)

This work presents the results of a study on communities of terrestrial mollusks on the calcareous substrates in forest-steppe zone in the Middle Volga region. On the calcareous substrates, we observed a decrease in the proportion of steppe species in the open habitats from the south to the north and in the forest phytocenoses. Three rare species were encountered: Laciniaria plicata, Truncatellina costulata и Pupilla bigranata. The first species was found in the Primokshinsky forest (Penza region), the second in open and forest biotopes and the third in calcareous outcropes. Taking into account the ancient habitats of the last two species in the Zhiguly Mountains, we can assume that the observed biotopes would be relict.