title: Water quality variables and pollution sources shaping stream macroinvertebrate communities.
abstract: In 2015, over 90 percent of German rivers failed to reach a good ecological status as demanded by the EU Water Framework Directive (WFD). Deficits in water quality, mainly from diffuse pollution such as agricultural run-off, but also from wastewater treatment plants (WWTPs), have been suggested as important drivers of this decline in ecological quality. We modelled six macroinvertebrate based metrics indicating ecological quality for 184 streams in response to a) PCA-derived water quality gradients, b) individual water quality variables and c) catchment land use and wastewater exposure indices as pollution drivers. The aim was to evaluate the relative importance of key water quality variables and their sources. Indicator substances (i.e. carbamazepine and caffeine indicating wastewater exposure; herbicides indicating agricultural run-off) represented micropollutants in the analyses and successfully related water quality variables to pollution sources. Arable and urban catchment land covers were strongly associated with reduced ecological quality. Electric conductivity, oxygen concentration, caffeine, silicate and toxic units with respect to pesticides were identified as the most significant in-stream predictors in this order. Our results underline the importance to manage diffuse pollution, if ecological quality is to be improved. However, we also found a clear impact of wastewater on ecological quality through caffeine. Thus, improvement of WWTPs, especially preventing the release of poorly treated wastewater, will benefit freshwater communities.
authors.affiliation: Senckenberg Research Institute and Natural History Museum Frankfurt, Department of River Ecology and Conservation, Clamecystrasse 12, 63571 Gelnhausen, Germany; Goethe University Frankfurt am Main, Faculty of Biology, Department Aquatic Ecotoxicology, Frankfurt am Main, Germany. Electronic address: elisabeth.berger@senckenberg.de.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Berger
authors.affiliation: Senckenberg Research Institute and Natural History Museum Frankfurt, Department of River Ecology and Conservation, Clamecystrasse 12, 63571 Gelnhausen, Germany; University of Duisburg-Essen, Faculty of Biology, Department of River and Floodplain Ecology, Essen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Haase
authors.affiliation: Senckenberg Research Institute and Natural History Museum Frankfurt, Department of River Ecology and Conservation, Clamecystrasse 12, 63571 Gelnhausen, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Kuemmerlen
authors.affiliation: Senckenberg Research Institute and Natural History Museum Frankfurt, Department of River Ecology and Conservation, Clamecystrasse 12, 63571 Gelnhausen, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Leps
authors.affiliation: Quantitative Landscape Ecology, Institute for Environmental Sciences, University Koblenz-Landau, Landau, Germany.
authors.forename: Ralf Bernhard
authors.initials: RB
authors.lastname: Schäfer
authors.affiliation: Senckenberg Research Institute and Natural History Museum Frankfurt, Department of River Ecology and Conservation, Clamecystrasse 12, 63571 Gelnhausen, Germany; Goethe University Frankfurt am Main, Faculty of Biology, Department Aquatic Ecotoxicology, Frankfurt am Main, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sundermann
mesh_terms: D000383:Agriculture; D000818:Animals; D004784:Environmental Monitoring; D007448:Invertebrates / Q000502:physiology*; D045483:Rivers / Q000737:chemistry; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality
chemical_list: D014874:Water Pollutants, Chemical
keywords: Benthic invertebrates; Ecological quality; Micropollutants; Multiple stressor analysis; Point source pollution; Wastewater