The role of biomarkers in environmental assessment (5). Invertebrate populations and communities.

Although a number of biomarkers of pollutant exposure have been identified in invertebrate species, direct linkage with changes at population and/or community levels are poorly documented and, despite the ecological importance of invertebrates, there is no conclusive evidence that individual measurements of biochemical parameters may allow the effects of pollutants on populations and communities to be predicted. Among the various biochemical parameters used as biomarkers in invertebrates exposed to pollutants in the field, only those for which changes at population or community level can be suggested are discussed in the present review. At population and community levels, the development of resistance to pesticides and changes in behaviour, reproduction and development are analysed as putative consequences of biochemical and physiological alterations. Limits to the use of biochemical parameters as biomarkers of invertebrate exposure to pollutants are discussed. Future research trends and experimental approaches to the validation of invertebrate biomarkers in environmental pollution assessment are suggested.