Research needs for predictive multispecies tests in aquatic toxicology

Aquatic multispecies tests are increasingly used to assess the fate and effects of pesticides in Europe. The rationale for their use, although originally based upon ecological arguments, is now more likely to be based upon uncertainties surrounding the true exposure of organisms in natural ecosystems. This shift in rationale promotes the design of more focused studies, but does not overcome difficulties associated with the extrapolation of mesocosm and microcosm results to natural systems. Priorities for further research into these systems should be the extent to which results can be repeated and reproduced, and the level of precision and accuracy of predictions from microcosms and mesocosms to natural ecosystems.