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Flood-pulse and riverscape dynamics in a braided glacial river
Florian Malard1, Urs Uehlinger, Rainer Zah
1UMR CNRS 5023, Ecologie des Hydrosystèmes Fluviaux, Université Claude Bernard Lyon, 43 Bd 11 Novembre 1918, 69622 Villeurbanne, France. malard@univ-lyon1.fr
Ecology
|April 11, 2006
Summary
Braided river dynamics significantly alter aquatic habitats, impacting biodiversity. Understanding these riverscapes is key to managing river ecosystems and their inhabitants.
Area of Science:
- River ecology
- Geomorphology
- Hydrology
Background:
- River ecosystems are increasingly recognized as dynamic riverscapes.
- Braided rivers exhibit complex changes in extent, composition, and configuration due to discharge variations.
- Quantifying these riverscape dynamics is crucial for understanding ecosystem processes and biodiversity.
Purpose of the Study:
- To quantify the monthly changes in the riverscape dynamics of a braided glacial river.
- To assess the effects of seasonal riverscape changes on zoobenthic density, epilithic algae, and hyporheos.
- To link hydrological processes to riverscape composition and configuration.
Main Methods:
- Monthly measurements of channel length, spatial arrangement, and age distribution over two annual cycles.
- Analysis of clear (groundwater-fed) and turbid (glacial-fed) channels.
- Integration of biological data on zoobenthos, algae, and hyporheos.
Main Results:
- Riverscape composition and configuration changed predictably with discharge, with ~30% renewal monthly.
- Turbid channel length increased with discharge; clear channel length increased up to a threshold.
- Habitat availability and spatial arrangement influenced invertebrate density and algal standing crop.
Conclusions:
- Hydrological pulsing drives predictable, yet complex, changes in braided riverscape structure.
- Riverscape dynamics directly impact aquatic biodiversity and bioproduction.
- Quantifying riverscape dynamics is essential for effective river ecosystem management.
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