Combining biomarker and community approaches using benthic macroinvertebrates can improve the assessment of the ecological status of rivers

Indices based on community structure provide a global ecological status of the biological communities but they are of limited value as early-warning indicators of contamination. Almost two decades after the Water Framework Directive (2000/60/EC) was adopted, we reviewed publications that measured biomarkers in benthic macroinvertebrates in biomonitoring programmes of fluvial systems. The focus was on studies that attempted to incorporate both biomarkers and community-based approaches in the evaluation of the ecological status of rivers and streams. Overall, the data showed that biomarker measurements in benthic macroinvertebrate species can offer complementary information on the factors threatening these communities. This information is particularly useful for water authorities, in order to take actions before a system collapses into a state from which recovery is difficult or impossible. Gaps in need to be addressed for rapid and efficient implementation of biomarkers in benthic macroinvertebrates in routine wide-scale monitoring are discussed. In particular, site-specific baselines have to be defined, taking into account the influence of biotic and abiotic factors on these biochemical responses. Further studies, including different biomarkers, environmental stressors, macroinvertebrate taxa and river types, will provide crucial information on how to establish adequate biomarker strategies to indicate future ecological damage.