Under CopyrightSchäfers, ChristophChristophSchäfers2022-03-0701.10.201412.2.20152013https://publica.fraunhofer.de/handle/publica/27978610.24406/publica-fhg-279786The presented work was performed by Christoph Schäfers and his staff at the Fraunhofer Institute for Molecular Biology and Applied Ecology IME in Schmallenberg, Germany. This summarizing report serves as a habilitation thesis in ecotoxicology at the University Koblenz-Landau. We developed and improved experimental approaches to identify the ecological effects of chemical exposure, aiming to minimize uncertainties of regulatory assessments. For hazard assessment of substances, projects on invertebrate species sensitivity distributions in ground and surface water, (endocrine) effects on sensitive fish life stages and performances, and effects on aquatic communities in large-scale microcosms are presented. For water quality evaluation, habitat-specific approaches and multivariate methods to aquatic invertebrate community monitoring are shown. General conclusions are followed by an outlook to current and future research issues, especially with respect to a landscape-level risk assessment.enhabilitation thesis