Testing the Effectiveness of Site Preparation Techniques for Wetland Prairie Restoration

In collaboration with the West Eugene Wetland Partnership, the University of Oregon, City of Eugene, and Lane Council of Governments established a large, replicated study to examine the effectiveness of various wet prairie restoration site preparation techniques. The effort was funding through an EPA Wetland Program Development Grant. The objective of this research was to guide future restoration activities by assessing these site preparation techniques in terms of i) plant community structure, diversity, and productivity, ii) seasonal measurements of functional soil ecosystem attributes, and iii) changes in chemical and physical attributes of the soil.

This experiment was implemented on an 11-acre site (previously in Lolium multiflorum production) west of Eugene, Oregon beginning in 2004. Site preparation techniques were chosen to i) kill the existing vegetation (tilling, herbicide application), ii) decrease viable seeds in the seed bank (solarization, thermal weed control, herbicide application), and iii) reduce competition from invasive species (nutrient immobilization). These techniques were implemented in 10 different combinations with 5 replicates of each treatment. After 1-year post-treatment, none of the treatments resulted in a significant change of belowground responses, but aboveground plant communities were distinctly different from one another, with solarization and a fall herbicide application being the most effective at decreasing exotic cover. In subsequent years, plant communities became more similar, regardless of treatment type.