Plant and Soil Responses to Experimental Restoration Techniques in a Wet Prairie

EPA Grant Number: F5F11492
Title: Plant and Soil Responses to Experimental Restoration Techniques in a Wet Prairie
Investigators: Pfeifer-Meister, Laurel E.
Institution: University of Oregon
EPA Project Officer: Lee, Sonja
Project Period: October 1, 2005 through September 30, 2008
Project Amount: $109,142
RFA: STAR Graduate Fellowships (2005) RFA Text |  Recipients Lists
Research Category: Academic Fellowships


The objective of this research is to examine a large number of common wet prairie restoration techniques in a replicated design to assess:

  1. the response of plant community structure, diversity, and productivity, including the relative response of native and exotic species,
  2. seasonal measurements of a large number of functional soil ecosystem attributes related to carbon and nutrient cycling,
  3. changes in physical and chemical attributes of the soil,
  4. and the extent to which plant and soil responses are interactive and mutually dependent.


This experiment is being implemented on a 4.5 ha site west of Eugene, Oregon. The site was an undrained agriculture field used in the production of seed for Lolium multiflorum (annual ryegrass) and fertilized twice annually with nitrogen and phosphorous until the spring of 2004. Site preparation techniques were chosen to:

  1. kill the existing vegetation (tilling, herbicide application),
  2. decrease viable seeds in the seed bank (solarization, thermal weed control, herbicide application),
  3. and reduce competition from invasive species (nutrient immobilization).

These techniques were implemented in 10 different combinations with 5 replicates of each treatment. Treatment implementation and seeding of 15 native species were completed in October of 2004 by the West Eugene Wetland Partnership. Plant cover, frequency, and productivity (above and belowground) data will be collected for two years in the 50 experimental plots as well as in three reference wet prairies. Additionally, seasonal soil functional, physical, and chemical measurements (including net N mineralization, extractable PO43- , microbial biomass C, N, P, aerobic and anaerobic microbial respiration, denitrification, soil total C, N, and P, texture, pH, bulk density, and moisture) will be collected in year two of the experiment.

Expected Results:

This experiment takes an ecosystem approach to wetland restoration by considering responses in soil functional, chemical, and physical attributes, plant community structure, and the relationship between the two. By examining the relationship between all of these response variables, a more complete and useful understanding of restoration techniques on wetland functioning will be achieved. The criteria for success of wetland restorations are often narrowly defined, and there may be trade-offs among certain response variables on what constitutes the ‘best’ site preparation technique. These results will provide essential comparative information on different site preparation techniques to wetland and restoration scientists and practitioners.

Supplemental Keywords:

restoration, wet prairie, nutrient cycling, plant community structure, diversity, site preparation, tilling, herbicide, thermal weed control, nutrient immobilization, solarization, glyphosate, Willamette Valley, West Eugene Wetlands, seed bank, competition, Lolium multiflorum, exotic species,, Scientific Discipline, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Restoration, Environmental Monitoring, Terrestrial Ecosystems, Ecology and Ecosystems, Aquatic Ecosystem Restoration, wetlands, exotic plant species, nutrient loading, invasive plant species, wet prairie restoration, ecological recovery, wetland restoration, aquatic ecosystems, nitrogen compounds, environmental rehabilitation

Progress and Final Reports:

  • 2006
  • 2007
  • Final