Abiotic and biological aspects of spring biotopcs in the Paleozoic Rhenish shield und the Hessian sandstone plate (Hesse, Germany) were compnred. Springs in the Rhenish shield have fluctuating discharges with a risk of drying out in summer, and high ranges of water temperature. In contrast, springs in the sandstone area have well-balanced discharge and temperature regimes. The bioiogical aspect of this study investigates general questions of community structure and examples of autecological adaptation of life cycles. The spring community composition is characterized in tems of environmental factors and trophic relationships in the water column und in the adjacent limnic-terrestrial interface. Lifecycle adaptations of Synagapetus are typical for inhabitants of springs with unstable discharge regimes. Its eggs are resistant to drought and the larvae possess ventilation mechanisms which are efficient even in periods of low discharge. As an example, the life-cycles of several Apataniinae are discussed in the context of adaptation to cold springs, and their embryonic development is compared to those of eurytopic Trichoptera. Finally, synecological aspects of the spatial and temporal distributions of several Trichoptera species, as recorded in emergence traps, are described. Closely related species show more or less strong niche separation.