Land snail faunas along an environmental gradient in the Altai Mountains (Russia)

Abstract

Many land snail species of the European Pleistocene have recently been reported from Central Asia. The ecological conditions in which they live, however, are little known. We studied vascular plants and land snails along a climatic gradient in the Russian Altai Mountains. We recorded 566 plant and 40 mollusc species. In the most continental part of the Altai we discovered living Pupilla loessica, a land snail now extinct in Europe and which is an important indicator of palaeoenvironments of the European Pleistocene. We inferred thermal ranges of the snail species in the Altai and observed considerable differentiation among the species. Moisture requirements of the species were indirectly estimated by using moisture indicator values of plant species co-occurring with the snails. They reveal local moisture requirement patterns that cannot be inferred from climate data. Snails are sorted along our transect; only a few species occur throughout the Altai. Many snails are able to occupy various plant communities. A few species may be indicators of vegetation types. For palaeoreconstructions, mollusc species are apparently good indicators for climate but less so for vegetation types.