Impacts of artificial flow fluctuations on cyprinid fishes
Abstract
Wider research context Artificial sub-daily flow fluctuations (hydropeaking) are considered one of the most significant impacts on rivers downstream of dams and have been subject to a growing number of studies in the last decades. Nevertheless, so far, cyprinid fish have hardly been considered, neither in Austria nor worldwide, and extensive knowledge gaps remain. Objectives Therefore, we will conduct quantitative population studies and experimental approaches to test the impact of hydropeaking on two cyprinid target species for conservation and hydromorphological restoration: the barbel (Barbus barbus) and the nase (Chondrostoma nasus). Our aim is (1) to study how hydropeaking affects cyprinid fish populations nation-wide, as well as (2) to assess how single and multiple hydropeaking events impact early life-stages (larvae and juveniles) of the target species. We aim to answer the research questions by integratively working on two scales: on the national scale through statistical modelling and on the local scale through experimental approaches. Methods On the large scale, we consolidate an extensive database containing existing biological, hydrological, and morphological data, as well as other pressure variables of Austrian rivers. By modelling the effects of hydropeaking on cyprinid populations, we can assess their response on a nation-wide scale as well as identify and detangle the effects of other stressors in riverine ecosystems. We expect that cyprinid fish populations show significant responses to river hydrology, whereby low-intensity hydropeaking sites will have a better population status than high-intensity ones. Furthermore, we assume that co-occurring pressures such as river morphology, connectivity, land use or fish predators will have a strong influence on the studied populations as well. On the local scale, we conduct hydropeaking experiments in outdoor flumes to detect the effect of different hydropeaking scenarios on drift and stranding rate of individual fish. We also incorporate gravel bank morphology and assess the additional role of daytime on drift and stranding of larval and juvenile nase and barbel. We expect that hydropeaking will lead to greater drift and stranding rates in comparison to control treatments, whereby increased ramping rates will exacerbate the response of fish. Furthermore, gravel bank structure and time of day will be essential co-variables, influencing drift and stranding rates. In general, juveniles should be more resistant to hydropeaking than larvae. Level of originality The outcomes will benefit the ongoing discussion on hydropeaking mitigation by providing a more profound knowledge on the effects of artificial sub-daily flow fluctuations. The combination of modelling and experimentation will ensure that conclusions are neither simplified nor generalized but allow derivation of best management recommendations.
keywords hydropeaking cyprinid fishes river hydropower experimental flumes
Publikationen
Project staff
Stefan Schmutz
Univ.Prof. Dipl.-Ing. Dr.nat.techn. Stefan Schmutz
stefan.schmutz@boku.ac.at
Tel: +43 1 47654-81202
Project Leader
01.01.2021 - 30.09.2024
Stefan Auer
Dipl.-Ing. Stefan Auer
stefan.auer@boku.ac.at
Tel: +43 1 47654-81250
Sub Projectleader
01.01.2021 - 30.09.2024
Simon Führer
Dipl.-Ing. Simon Führer B.Sc.
simon.fuehrer@boku.ac.at
Tel: +43 1 47654-81241
Sub Projectleader
01.01.2021 - 30.09.2024
Daniel S. Hayes
Dr. Daniel S. Hayes
daniel.hayes@boku.ac.at
Tel: +43 1 47654-81223
Sub Projectleader
01.01.2021 - 30.09.2024