Assessing chemical stress in aquatic ecosystems: remarks on the need of an integrative approach

This paper that serves as a prelude to a series of papers on the theme 'Pesticide stress in freshwater ecosystems', has three main objectives. First it outlines the importance of ecological expertise assessing the risks of discharge of pesticides into aquatic environments; second, it discusses possible contributions of ecotoxicological experiments to ecological theory; and third, it advocates the need for an integrative approach in stress-ecology. This approach is based on descriptive ecology, experimentation in the laboratory and in model ecosystems, and on the development of computer simulation models