This work applies advanced sampling (mark-release-recapture) and comparative approaches addressing the patterns in composition, structure and variability of larval trematode communities in three species of gastropod molluscs (Lymnaea stagnalis, Planorbarius corneus and Radix auricularia) at two nested scales of community organisation in typical Central European eutrophic environments. Hypothesis-testing with the application of null-model analyses, logistic regression modelling and multivariate randomisation techniques, revealed determinants of transmission rates, levels of infection and community structure in freshwater snail hosts in Central Europe and elucidated the mechanisms linking the spatial and temporal environmental variability with the action of complex community assembly rules in freshwater pulmonate snails.