Modellierung der Habitatsdynamik in Schwallstrecken unterschiedlicher Morphologie unter Berücksichtigung der Habitatsgräferenzen von Fischen

• Forschungsstelle: BFE
• Projektnummer: SI/500959
• Projekttitel Englisch: Modelling fish habitat dynamics in hydropeaking rivers considering different morphology and habitat preference – current state, needs for improvement, and guidelines for application

Schlüsselwörter (Englisch)

hydropeaking, physical habitat modelling, mitigation, river morphology, habitat preference

Kurzbeschreibung (Deutsch)

Habitateignungsmodellierung ist zurzeit die einzige Methode, um die ökologische Wirkung einer Schwallsanierung quantitativ abzuschätzen. Die Modellierung setzt verlässliche Angaben zur Habitatspräferenz sowie zum Einfluss der Morphologie voraus. Wir modellieren die Habitatsdynamik in morphologisch verschiedenartigen Schwallstrecken und identifizieren Strukturen mit schwallmindernder Wirkung, unter Verwendung unterschiedlicher Habitatspräferenzen.

Kurzbeschreibung (Englisch)

Habitat suitability modelling is currently the only methodology capable of providing quantitative estimates of the ecological effects of hydropeaking mitigation. The model prescribes reliable information with regard to habitat preferences in combination with morphological characteristics. Habitat dynamics in hydropeaking reaches with different morphologies are modelled in order to identify structures which can reduce the impact of hydropeaking, considering a spectrum of indicator organisms and their habitat preferences.

Schlussbericht (Englisch)

Habitat suitability modelling is currently the only methodology capable of providing quantitative esti-mates of the ecological effects of hydropeaking mitigation. Two aspects have remained understudied in research on the effects of hydropeaking and respective mitigation measures: the impact of the river morphology on habitat availability and persistence, and the effect of natural variability in the biological input data on model outcomes. The present interdisciplinary study aimed at i) analysing the availability and variability of habitat suita-bility data determined across different study systems for two fish species, ii) quantifying the impact of variability in fish habitat suitability data on the outcome of habitat suitability modelling for three differ-ent morphologies under three different flows, and iii) determining the hydraulic and ecological effects of instream structures. The available habitat suitability data was inconsistent. We observed a pronounced variability in the suitability curves across studies, also within an age class of the same species. Our results highlight the importance of the interaction between morphology and flow: The near-natural reach provided the largest amount of suitable area (SA) for both species and the channelized reach the smallest. This pattern was consistent across the three different flows. Datasets from the same study tended to agree in which river cells had the highest suitability. It was shown that habitat quality and availability is much higher in a morphologically heterogeneous near-natural reach compared to a moderately and heavily modified one. Furthermore, the area of habi-tats with a low sensitivity against flow fluctuations was significantly higher in the heterogeneous reach. No general relationship between certain types of gravel bars and impact on habitats could be found. However, a permanently wetted side channel was identified as most advantageous morphological feature to mitigate hydropeaking impacts.

Auftragnehmer/Contractant/Contraente/Contractor:
EAWAG
SJE - Ecological Engineering GmbH (subcontractor)

Autorschaft/Auteurs/Autori/Authors:
Weber,Christine
Schneider,Matthias
Junker,Julian
Kopecki,Iana
Alexander,Timothy

Zugehörige Dokumente

• Modelling fish habitat dynamics in hydropeaking rivers considering different morphology and habitat requirements | Current state, needs for improvement, and guidelines for application - Final report [PDF] 3'171 kB