Examining progressive changes in stream habitat and communities following restoration

Background/Question/Methods

Although each year a great deal of time and money is invested to restore biodiversity and habitat complexity within historically degraded streams, many resource agencies and conservation organizations are unable to dedicate sufficient resources to monitor and evaluate these restoration efforts.  Consequently, little is known about how stream restoration practices impact changes in stream habitat and communities over time.  The objective of this project was to examine how stream habitat and communities in the upper Blue River, WI responded to Trout Unlimited restoration efforts over a nine year period.  In-stream habitat, macroinvertebrates, and fish were sampled at 11 different sites along the Blue River from 2004-2012.  Pre-restoration surveys were compared to post-restoration surveys collected at regular intervals following restoration.  Data from restored sites were also compared to those from completely unrestored sites located within the same stream section and sampled at the same intervals.

Results/Conclusions

Habitat and communities in the Blue River appeared to go through a succession following restoration practices.  After just a year following restoration, sites had less width, fine substrates, macrophytes, and bank erosion, but had more invertebrates, sculpins, and trout.  Over time restored sites maintained relatively consistent fish communities, but had increased levels of fine sediments, emdeddedness, and macrophytes.  This suggests that stream habitat and communities respond rapidly to restoration and then go through continuous adjustments as time goes on.  Given limited opportunities to evaluate restoration efforts, resource agencies and conservation organizations should be aware that assessing restoration is indeed time dependent.