Wednesday, May 28, 2008 - 3:30 PM
479

Does restoration enhance stream ecosystem resistance and resilience to storms?

Timothy J. Hoellein1, Jennifer L. Tank1, Sally A. Entrekin1, and Emma J. Rosi-Marshall2. (1) Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, (2) Biology, Loyola University Chicago, Chicago, IL 60626

The re-introduction of large wood is an increasingly common stream restoration technique intended to increase particulate organic matter (POM) retention and diversify habitat. We hypothesized that wood addition may also increase stream ecosystem resistance and resilience to disturbance via increased POM retention during storms. We predicted resistance (magnitude of change) and resilience (speed of recovery) could be quantified using stream nutrient spiraling parameters. In May 2004, we added 25 logs to 100m reaches of 3 forested streams in the Upper Peninsula of Michigan. In 2007, we measured nitrate and phosphate uptake via short-term additions before and after multiple storms in treatment and upstream control reaches, along with POM import/export at high and low flows. Nitrate and phosphate uptake was generally higher in treatment relative to control reaches 1-7 days following a storm, with differences diminishing over time. During high flows, net POM export was higher in control relative to treatment reaches. Our results suggest that wood addition increased ecosystem resistance as indicated by nutrient uptake rates, but that our study streams naturally exhibit high resilience. Our study provides insight into the long-term efficacy of wood addition as a restoration tool, supporting its utility to sustain ecological function following storms.


Web Page: Disturbance, Large wood, Nutrient uptake