Patterns of Land Snail Assemblages along a Fine-Scale Moisture Gradient

Abstract

ABSTRACT We studied changes of terrestrial snail assemblages over a gradient of soil moisture using 60 sampling plots in the White Carpathian Mountains of the south-eastern Czech Republic. We used within-site design to control for confounding effects of site characteristics other than humidity, and we directly measured soil moisture along nine transects at distinct locations. Each transect had from 4 to 16 plots, and it was laid down from wet calcium-rich spring fen habitats to semi-dry meadows in the fen surroundings. We observed a sharp moisture gradient along each transect, with the measured soil moisture varying from 97% in fen plots to 19% in semi-dry grassland plots. Altogether 29 land snail species and 4,213 live individuals were collected. Species richness of land snails varied from 2 to 11 species per plot. However, we did not observe any significant linear or unimodal response of species richness or total abundances to measured soil moisture. In contrast, sharp compositional changes along studie...