Eutrophic status influences the impact of pesticide mixtures and predation on Daphnia pulex populations

Pesticides, nutrients, and ecological stressors such as competition or predation co-occur in freshwater ecosystems impacted by agricultural pollution. The extent to which combinations of these stressors affect aquatic populations and the role of nutrients availability in modulating these responses requires further understanding. In this study, we assessed how pesticides affecting different taxonomic groups and predation influence the response of Daphnia pulex populations under different trophic conditions. An outdoor experiment was designed following a factorial design, with the insecticide chlorpyrifos, the herbicide diuron, and predation by Notonecta sp. individuals as key stressors. The single impact of each of these stressors, and their binary and tertiary combinations were evaluated on D. pulex abundance and population structure under mesotrophic and eutrophic conditions for 21 days. Data were analysed using generalized linear mixed models estimated by means of a novel Bayesian shr...