Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Invertebrate drift and benthic exhaustion during disturbance: Response of mayflies (Ephemeroptera) to increasing shear stress and river‐bed instability
AbstractWe manipulated hydraulic conditions over patches of sands and fine gravels in an upland, gravel‐bed river using a portable flume and assessed changes in the drift rates of three mayflies (Baetis, EcdyonurusandCaenis). On average, manipulations doubled water velocity in experimental locations and resulted in shear stresses that exceeded the critical threshold for entrainment of patch sediments. Bedload transport rates were used as an indicator of bed disturbance during the manipulations. Partial Least Squares Regression (PLSR) indicated that between 59 and 81% of the variation in the drift rates of the three taxa could be accounted for by the combined effects of shear stress and bed disturbance. Shear stress was more important than bed disturbance as a cause of drift inEcdyonurusandBaetis, while forCaenisthe two variables were equally important. Drift rates fell markedly (10‐fold) after only 5 mins of increased shear stress and bed disturbance. The experiments indicate that (a) dramatic loss of mayflies can occur rapidly from patches of fine and relatively unstable sediment during periods of increased discharge and (b) for some taxa, losses may cause a depletion of the benthic source‐pool and hence result in the exhaustion of supply. Copyright © 2009 John Wiley & Sons, Ltd.
Invertebrate drift and benthic exhaustion during disturbance: Response of mayflies (Ephemeroptera) to increasing shear stress and river‐bed instability
AbstractWe manipulated hydraulic conditions over patches of sands and fine gravels in an upland, gravel‐bed river using a portable flume and assessed changes in the drift rates of three mayflies (Baetis, EcdyonurusandCaenis). On average, manipulations doubled water velocity in experimental locations and resulted in shear stresses that exceeded the critical threshold for entrainment of patch sediments. Bedload transport rates were used as an indicator of bed disturbance during the manipulations. Partial Least Squares Regression (PLSR) indicated that between 59 and 81% of the variation in the drift rates of the three taxa could be accounted for by the combined effects of shear stress and bed disturbance. Shear stress was more important than bed disturbance as a cause of drift inEcdyonurusandBaetis, while forCaenisthe two variables were equally important. Drift rates fell markedly (10‐fold) after only 5 mins of increased shear stress and bed disturbance. The experiments indicate that (a) dramatic loss of mayflies can occur rapidly from patches of fine and relatively unstable sediment during periods of increased discharge and (b) for some taxa, losses may cause a depletion of the benthic source‐pool and hence result in the exhaustion of supply. Copyright © 2009 John Wiley & Sons, Ltd.
Invertebrate drift and benthic exhaustion during disturbance: Response of mayflies (Ephemeroptera) to increasing shear stress and river‐bed instability
River Research & Apps
Gibbins, Chris (Autor:in) / Batalla, Ramon J. (Autor:in) / Vericat, Damià (Autor:in)
River Research and Applications ; 26 ; 499-511
01.05.2010
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Invertebrate Drift in Natural Versus Modified River Channels: Implications for Salmonid Fish
| British Library Conference Proceedings | 2001