The research group “Ecosystem Pollution Dynamics“ is engaged in the analysis and evaluation of the chemical pollution of small stream ecosystems. A particular emphasis is placed on the exposure, effect, and risk assessment for pesticides in small agricultural streams. The pollution scenarios are thereby evaluated in the context of pollution gradients, i.e., unpolluted, slightly polluted and heavily polluted stream sites are investigated comparatively. The study areas encompass stream catchments exhibiting contrasting land-use patterns (e.g., nature protection areas, urban regions, agricultural areas), thereby offering a range of diverse contamination scenarios. The Eußerthal Ecosystem Research Station (EERES), situated in the Pfälzerwald-Nordvogesen Biosphere Reserve (southwestern Germany), serves as an unpolluted reference site for small lotic ecosystems. Methods and field surveys employed within our research group entail the quantification of pesticides and other chemical stressors in surface waters, hydromorphological surveys, assessments of the aquatic biodiversity and ecosystem functions, as well as land use analyses employing Geographic Information Systems (GIS).