A simple fish-based approach to assess the ecological quality of freshwater reservoirs in Central Europe
The assessment of ecological quality in freshwater ecosystems is a key issue in many countries, but conditions for the development of assessment methodologies are often country-specific. This study proposes a simple methodology for the assessment of the ecological potential of reservoirs based on fish communities using a dataset covering major environmental and pressure gradients in reservoirs in the Czech Republic. Fish data obtained by gillnet sampling were correlated with a proxy of eutrophication as a key indicator of anthropogenic pressure for selecting appropriate fish-based indicators, establishing scoring criteria and developing the index of ecological quality. Expert judgement was also used to select potential fish indicators. Nine indicators were selected for the final fish-based index, fulfilling the criteria required by the Water Framework Directive. Two steps were used to validate the fish-based index quantification of its inter annual stability and sensitivity analysis of individual indicators. Finally, the index was compared to a previously developed general index for Central and Western Europe. Our study demonstrates that a combination of expert judgement and strict validation methods can result in an informative assessment of the ecological conditions, which can help identify conservation and restoration priorities.
Auteurs du document :
Petr Blabolil, Milan Říha, Daniel Ricard, Jiří Peterka, Marie Prchalová, Mojmír Vašek, Martin Čech, Jaroslava Frouzová, Tomáš Jůza, Milan Muška, Michal Tušer, Vladislav Draštík, Zuzana Sajdlová, Marek Šmejkal, Lukáš Vejřík, Josef Matěna, David S. Boukal, David Ritterbusch, Jan Kubečka
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Mots clés :
Artificial lakes, eutrophication, fish indicators, gillnets, index sensitivity, WFD, Lac artificiel, eutrophisation, indicateur de poisson, filets maillants, directive cadre sur l'eau