Abstract: Session E 1:30 pm (Back to Session E)
Challenges of Evaluating Success of Stream Restoration through Improvement in Macroinvertebrate Assemblages
Authors: Jeniffer Lynch, Ashley Ficke, and Chris Craft
Information on efficacy of stream restoration techniques to improve macroinvertebrate assemblages is limited due to a lack of monitoring activities pre and post-restoration. In addition, the recovery trajectories of such assemblages are often complex and nonlinear. Naturally high variability in many macroinvertebrate community health metrics can hinder interpretation of the extent to which assemblages are or are not recovering. The presence of water quality or nutrient supply issues are typically not addressed by channel restoration projects and can also limit improvements in macroinvertebrate assemblages following these projects. These factors make the development of objective criteria to evaluate macroinvertebrate community response to restoration difficult. The Stream Quantification Tools (SQTs) currently in use in North Carolina and Wyoming are designed to apply the principles of the Stream Functions Pyramid Framework to evaluate functional recovery of streams. These SQTs quantify “functional uplift” within a stream reach and provide a standardized and consistent approach to measuring changes in macroinvertebrate assemblages and other function-based parameters. They also provide guidance on how to measure and interpret such uplift in the context of stream restoration. In the existing SQTs, the metrics evaluated for assessment of uplift in macroinvertebrate communities are a combination of multi-metric indices developed specifically for each state, comparison of observed over expected indices, and the number of Ephemeroptera, Plecoptera, and Trichoptera taxa. A SQT for Colorado is currently in development and expected to be similar to the Wyoming SQT. Use of the SQT in Colorado is a promising development that will allow quantification of the beneficial effects of restoration projects. In anticipation of its use, we present this synthesis of studies on macroinvertebrate responses to restoration that may be useful for SQT development in Colorado.