Do in-stream restoration structures enhance salmonid abundance? A meta-analysis

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Whiteway, Sarah L., Biron, Pascale M., Zimmermann, Andre, Venter, Oscar, Grant, James W. A.
• Other Authors: Donald A. Jackson
• Format: Article in Journal/Newspaper
• Language: English
• Published: NRC Research Press 2010
• Subjects: Large woody debris; Fresh water fauna; Habitat restoration; Trout populations; Juvenile salmonids; Fish populations; Atlantic salmon; Cutthroat trout; Weir placement; Brown trout; C1; 9605 Ecosystem Assessment and Management; 050206 Environmental Monitoring; Weir
• Online Access: https://espace.library.uq.edu.au/view/UQ:205469

Despite the widespread use of stream restoration structures to improve fish habitat, few quantitative studies have evaluated their effectiveness. This study uses a meta-analysis approach to test the effectiveness of five types of in-stream restoration structures (weirs, deflectors, cover structures, boulder placement, and large woody debris) on both salmonid abundance and physical habitat characteristics. Compilation of data from 211 stream restoration projects showed a significant increase in pool area, average depth, large woody debris, and percent cover, as well as a decrease in riffle area, following the installation of in-stream structures. There was also a significant increase in salmonid density (mean effect size of 0.51, or 167%) and biomass (mean effect size of 0.48, or 162%) following the installation of structures. Large differences were observed between species, with rainbow trout (Oncorhynchus mykiss) showing the largest increases in density and biomass. This compilation highlights the potential of in-stream structures to create better habitat for and increase the abundance of salmonids, but the scarcity of long-term monitoring of the effectiveness of in-stream structures is problematic.