EFFECTS OF STREAM SIMULATION DESIGN ROAD-STREAM CROSSINGS ON THE INVERTEBRATE COMMUNITY IN A NORTHERN FORESTED STREAM
Increasing storm magnitudes and undersized culverts are resulting in more failed road-stream crossings, economic losses, and impaired aquatic communities. Stream simulation design (SSD) is a geomorphic and ecologically-based approach to designing road-stream crossings that mimic natural channel structure, sediment, velocity, and depths. Previous research in Hawkins Creek, a headwater stream, demonstrated improvements in basal food resources and substrate diversity within the SSD culvert following restoration. We also compared invertebrate abundance and biomass in stream reaches above, within, and below the culvert, before and after SSD restoration. Improved habitat and food resources within the restored culvert resulted in increased total invertebrate abundance (6-17x) and biomass (9-12x) within 4-12 months and the colonization of 25 taxa that had not previously been found within the culvert. Proportionately, shredders (Tipula, Taeniopteryx), gatherers (Amphinemura, Paraleptophlebia), and filterers (Hydropsyche, Dolophilodes) responded most strongly to SSD culvert restoration with smaller increases in abundance and biomass of the scraper and predator functional feeding groups. Although aquatic organism passage and flood resiliency has been the primary design priorities of stream simulation design, our work in a northern forested stream demonstrated improved food web function within the restored SSD culvert.
Sue Eggert (Primary Presenter/Author), USDA Forest Service, Northern Research Station, firstname.lastname@example.org;
Coleson Wrege (Co-Presenter/Co-Author), University of Minnesota, email@example.com;