My personal field of research is the understanding and prediction of effects from chemical stressors on different biological levels. The main focus is on the use of various modelling techniques to link and extrapolate the effects between various environmental conditions as well as different biological levels. Model techniques are selected by the data availability and the ability to match the complexity and dynamics of biological systems incl. abiotic and biotic interactions. This implies an iterative process of data analysis, modelling and experimental research, in a way that new questions are raised by the models which will be followed by new experiments as input for further models. This iterative approach is an improvement compared to current approaches in the scientific community, in which mostly one modelling technique is used for several questions. The biological levels I investigated so far include interaction of xenobiotics with proteins (estrogen receptor, heat shock proteins), individuals (daphnia, chironomids, fish) and populations (daphnia, lemna, algae) as well as the impact of land use on terrestrial ecosystems (GraS-model). I developed equilibrium models to describe the interaction of xenoestrogens at the estrogen receptor, differential equations to simulate the life cycle of algae or grass, toxicokinetic-toxicodynamic models to describe the effects of time variable exposure of pesticides on individuals, agent based population models to simulate daphnia and trees, as well as spatial explicit models to simulate succession of terrestrial ecosystems at landscape level. The developed innovative modeling framework, integrating agent-based models linked with toxicokinetic-toxicodynamic models have a great potential in ecotoxicology as well as for the use within the regulatory framework for the legislation of pesticides.Specialties: ecotoxicity, ecology, individual-based modelling, population modelling, toxicokinetic-toxicodynamic modelling