Managing Structural Rehabilitation: Ecological Monitoring and Factors Driving Community Structure in a Restored Stream

Decades of anthropogenic pressure has devastated lotic ecosystems across the riverscapes of North America, resulting in the degradation of critical habitat and contributing to sharp declines in biotic integrity. In response, local stream restoration practices continue to increase in frequency, yet comparably little effort has been put forth to monitor these mitigation tactics, resulting in ambiguous results and limited project success. Lessons from the long-term rehabilitation and ecological monitoring of Kickapoo Creek in East-Central Illinois highlight some of the complex dynamics driving reach-scale restoration projects. Following implementation of artificial riffles, scouring keys, and riparian revegetation, we observed distinct temporal and spatial shifts in community structure in the six years following rehabilitation. While biotic integrity of reference assemblages remained in moderately low condition, monitoring in restored reaches depicted a delayed temporal response to rehabilitation, with biotic integrity being positively linked to additional instream habitat and development of a more beneficial channel morphology. Larger substrate sizes, submerged terrestrial vegetation, and newly-formed scour pools reduced siltation and provided necessary refuge to facilitate long-term recovery of degraded fish communities. We demonstrate the ability to use structural rehabilitation as an effective management tool to mitigate loss of biotic integrity through long-term alteration of critical habitat.