On Saturday, I gave a talk at the Midwest-Great Lakes Society for Ecological Restoration (SER) meeting in Wooster, Ohio. This meeting was my introduction to SER, and I was pleased by the mix of academics and practitioners and terrestrial and aquatic folks that the conference brought together. My favorite talks were about working on a restoration in the immediate aftermath of an oil pipeline burst and about creating a freshwater estuary at the mouth of urban Euclid Creek in Cleveland. I think this would be a great meeting to go to as a student: small, friendly, and full of interested folks and potential future employers. (There are even cash prizes for best student poster and talk…and farthest traveled.)
As the final stop of what has come to feel like a speaking tour this spring, I found myself condensing the stream restoration talk down to about 20 minutes. Here’s what the abstract said.
Jefferson, Anne J.*1, Sandra Clinton2, and Mackenzie Osypian2. Evaluating the effects of restoration on transient storage and ecosystem services in urban headwater streams
1. Kent State University, Kent, OH.
?2. University of North Carolina at Charlotte, Charlotte, NC. ?
In urban watersheds, the capacity of streams to provide essential ecosystem services is often limited as a result of channel straightening, incision and removal of geomorphic features. Stream restoration seeks to provide stream stability while reestablishing ecosystem services, but restoration alone may not mitigate the effects of watershed land-use change and urbanization. Stream restoration activities frequently impact transient storage and hyporheic exchange, the processes by which water movement is slowed down or temporarily detained at the surface or in the streambed. Transient storage and hyporheic exchange zones are important regulators of nutrient retention and stream temperature, and they harbor diverse biological communities. However, it is unknown how successful stream restoration activities are at creating ecologically effective storage and exchange zones that promote improved water quality and diversity. In Charlotte, North Carolina, we have evaluated restored and unrestored streams to quantify and compare transient storage. Our goal is to evaluate the relative success of restoration activities for ecosystem services in urban and forested watersheds. We measured increased transient storage and greater variability in upwelling and downwelling vertical hydraulic gradients in restored relative to unrestored reaches. However, restored reaches had lower hydraulic conductivity of bed sediments, which was likely related to the construction of the restoration. The net effect of restoration was to greatly increase in-stream transient storage, while not appreciably increasing hyporheic exchange. Evaluating the ecological effects from changes in transient storage was complicated by the effects of canopy removal around stream restoration projects, the combination of which resulted in higher water temperatures and reduced benthic diversity. While current practices of urban stream restoration may be successful in creating channel stability, coupling watershed-scale management of stormwater and nutrients with restoration techniques designed to enhance ecologically effective storage and exchange may be required for restoration success in a holistic sense.