Effects of pesticides on community structure and ecosystem functions in agricultural streams of three biogeographical regions in Europe

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  • Ralf B. Schäfer
  • Thierry Caquet
  • Katri Siimes
  • Ralf Mueller
  • Laurent Lagadic
  • Matthias Liess

There is a paucity of large-scale field investigations on the effects of organic toxicants on stream macroinvertebrate community structure and ecosystem functions. We investigated a total of 29 streams in two study areas of France and Finland for pesticide exposure, invertebrates and leaf-litter breakdown. To link pesticide exposure and community composition we applied the trait-based Species At Risk (SPEAR) indicator system. In the French region, pesticide stress was associated with a decrease in the relative abundance and number of sensitive species in the communities. The presence of undisturbed upstream reaches partly compensated the effects of pesticide contamination. Functional effects of pesticides were identified by a 2.5-fold reduction of the leaf-litter breakdown rate that was closely correlated with the structural changes in the contaminated streams. No effects of pesticides were observed in Finnish streams since contamination with pesticides was very low. In a follow-up analysis, the SPEAR approach successfully discriminated between reference and contaminated sites across different biogeographical regions, also including results of a previous field study in North Germany. Furthermore, change of the community structure was detectable at a concentration range as low as 1/100 to 1/1000 the acute 48 h-LC50 of Daphnia magna. Our findings demonstrate that pesticides may influence the structure and function of lotic ecosystems and that the SPEAR approach can be used as a powerful tool in biomonitoring over large spatial scales.

Original languageEnglish
JournalThe Science of The Total Environment
Issue number2-3
Pages (from-to)272-285
Number of pages14
Publication statusPublished - 01.09.2007

Bibliographical note

Funding Information:
The authors would like to thank Marc Roucaute, Martin Lodenius, Hans-Rudolf Voigt, Esa Tulosa, Peter von der Ohe, Björn Müller and all other people that contributed with work and facilities to the field study. We are indebted to Kari-Matti Vuori and Mikhail Beketov for their support in species determination. We are very grateful to Branislav Vrana and Albrecht Paschke who provided us with the passive samplers. Special thanks to Jochen Mueller and Klaus-Dieter Wenzel, who gave invaluable suggestions for the field study. We are indebted to Sophie Merle for data on pesticide measurements in Brittany. Finally, we would like to thank Bettina Egert for the chemical analyses. Carola Schriever, Peter von der Ohe, Mikhail Beketov and two anonymous reviewers provided valuable suggestions that improved the manuscript. Financial support was provided by the European Community (project SSPE-CT-2003-501997 “HArmonised environmental Indicators for pesticide Risk, HAIR”). The first author received funding through a scholarship of the “Studienstiftung des deutschen Volkes e.V.” (Bonn, Germany).

    Research areas

  • Chemistry - Macroinvertebrates, aquatic, Recovery, Leaf-litter breakdown, species traits