2026 Volume 36 Issue 2 Pages 161-172
To assess the effects of trial impounding on biota at a flood mitigation dam, we surveyed vegetation, fish, and amphibians from before trial impounding through three years after trial impounding, using environmental DNA (eDNA) to complement animal surveys. During construction, the clearing footprint was minimized and a pond was created to provide a waterside environment, considering environmental conservation and labor efficient maintenance. After trial impounding, vegetation succession progressed and amphibian spawning was observed, while no significant changes were detected in plant communities or in animal species detected by eDNA. Around the pond, flow action and sediment deposition during trial impounding formed diverse habitats, and germination of important species from upstream seed sources was confirmed. These results support the effectiveness of nature based measures that leverage natural recovery processes.
