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Abstract:
Abiotic and biological aspects of spring biotopes in the Paleozoic Rhenish Shield and the Hessian sandstone plate (Hesse, Germany) were compared. 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 biological aspect of this study investigates general questions on community structures and examples of autecological adaptation of life cycles. The spring community composition is characterized in terms of environmental factors and trophic relationships in the water column and in the adjacend limnic-terrestial interface. Life cycle adaptations of Synagapetus are typical for inhabitants of springs with unstable discharge regimes. Its eggs are resistant to drought and the larvae possess ventilation mechanismns which are efficient even in areas of low water velocity. As an example, the life-cycles of several Apataniinae are discussed in the context of adaption to cold springs, and their embryonic development is compared with 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.
