Das Nischenkonzept und seine Bedeutung für die Erklärung regionaler Verbreitungsmuster am Beispiel dreier Glossosomatidenarten (Trichoptera, Insecta)

The role of Hutchinson?s (1957) niche concept in explaining regional patterns of distribution is analysed using the example of three closely related glossosomatid species (Insecta, Trichoptera, Glossosomatidae). The study focuses on the species Agapetus fuscipes CURTIS, 1834, Synagapetus iridipennis MCLACHLAN, 1879 and Synagapetus moselyi (ULMER, 1938). The first part of the thesis describes the species? regional distribution throughout the study area situated in the north-western part of Hesse, Germany. In total 67 spring brooks are characterised taking into account a multitude of abiotic parameters. The relationship between colonisation events and the quality of these parameters is analysed. The ecological requirements of the species are described based on correlation analyses and multivariate statistics. The second part of the study focuses on the small-scale description of colonised microhabitats. For this purpose, a characteristic watercourse was chosen for each species. A description of habitat preferences is given for every aquatic stage of development and used for further characterisation of the species. Finally, the third part concentrates on the organism itself. The importance of the parameters flow velocity, water temperature, drought during pupal or embryonic stage, food intake and competition is analysed in field as well as laboratory experiments. The results of these three research parts are aggregated to a synoptic description of the ecological niche of each species. The characterisation of the three species obtained that way is suitable to explain their regional distribution.