title: Evaluation of hydropeaking impacts on the food web in alpine streams based on modelling of fish- and macroinvertebrate habitats.
abstract: Hydropeaking as a result of peak-load electricity production has been identified as one of the most significant pressures in alpine streams. Scouring of macroinvertebrates leads to downstream transport of aquatic organisms (catastrophic drift). Additionally, invertebrates are affected by periodic drying of wetted area during the dewatering of gravel bars and exposed areas along the banks. Even though fish are physiologically better adapted to switch to suitable habitats, artificial flow fluctuations may be followed by lethal stranding and quick alteration in habitat quantity and quality. Nevertheless, the interactions between pressures on fish and macroinvertebrates in terms of hydropeaking have not been investigated so far. The aim of this paper is to evaluate effects of flow fluctuations on potential epibenthic feeding grounds. Therefore, we evaluated changes in habitat distribution resulting from rapid flow fluctuations in river reaches with different river morphological characteristics, for five different macroinvertebrate taxa. Additionally, microhabitats for brown trout at two different life stages were calculated using representative peaking events (seasonal analysis) based on mid- to long term times series. Moreover, GIS-analysis allowed the evaluation of hydropeaking impacts (interaction) on both, macroinvertebrates and fish. In this study, it could be documented that feeding from the benthos for juvenile and subadult brown trout is inhibited during peak flow and is therefore reduced to times of base flow. Moreover, potential benthic feeding areas occurring at base flow have been found to increase with the level of morphological heterogeneity within analyzed river reaches. Likewise, hydrological sensitivity testing in terms of reducing ∆Q at different levels was performed and revealed that possible positive effects required heterogeneous river morphology as a precondition. However, this approach might be applied for estimating the impacts of hydrological mitigation measures in hydropeaked rivers concerning physical condition and/or growth rate of salmonids considering the river morphology of the investigated stream.
authors: Christian Doppler Laboratory for Advanced Methods in River Monitoring, Modelling and Engineering, Institute for Water Management, Hydrology and Hydraulic Engineering, Department for Water - Atmosphere - Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 107, 1190 Vienna, Austria. Electronic address: patrick.holzapfel@boku.ac.at.
authors: P
authors: P
authors: Holzapfel
authors: Institute of Hydrobiology and Aquatic Ecosystem Management, Department for Water - Atmosphere - Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Max-Emanuelstrasse 17, 1180, Vienna, Austria.
authors: P
authors: P
authors: Leitner
authors: Christian Doppler Laboratory for Advanced Methods in River Monitoring, Modelling and Engineering, Institute for Water Management, Hydrology and Hydraulic Engineering, Department for Water - Atmosphere - Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 107, 1190 Vienna, Austria.
authors: H
authors: H
authors: Habersack
authors: Institute of Hydrobiology and Aquatic Ecosystem Management, Department for Water - Atmosphere - Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Max-Emanuelstrasse 17, 1180, Vienna, Austria.
authors: W
authors: W
authors: Graf
authors: Christian Doppler Laboratory for Advanced Methods in River Monitoring, Modelling and Engineering, Institute for Water Management, Hydrology and Hydraulic Engineering, Department for Water - Atmosphere - Environment, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 107, 1190 Vienna, Austria.
authors: C
authors: C
authors: Hauer
mesh_terms: D000818:Animals; D001317:Austria; D004784:Environmental Monitoring; D005399:Fishes; D020387:Food Chain; D062070:Hydrology; D007448:Invertebrates; D008962:Models, Theoretical; D011210:Power Plants; D059205:Renewable Energy; D045483:Rivers; D014872:Water Movements
keywords: Brown trout; Epi-benthic feeding; Habitat modelling; River regulation