The malacofauna of 24 localities in the lower mountain zone of the Tatra Mts. includes 61 species. The richest communities have a high species diversity H’ and a moderate equitability J’. Communities of a lower species diversity H’ and of their equitability J’ similar as that of the former ones inhabit biotopes with limited food and habitat resources. A very low species diversity H’, along with extremely varied values of equitability J’, is characteristic for communi­ties inhabiting biotopes whose conditions are unfavourable for snails.
In the discussion on the structural parameters of the snail communi­ties in the Tatra Mts. and their qualitative similarity, connections between communities of the same kind appear several times. Qualitatively similar communities show similar structural parameters. A clear structural similarity is marked also when extreme qualitative differences occur. A strong pressure of natural and/or anthropogenous conditions results in the formation of communities of extremely distinct species composition.