Wetland   Prairie   Restoration   Research

The following research efforts were conducted specifically to inform the content of the Wetland Prairie Restoration Guide with funding provided by EPA Region 10. Additional wetland prairie related reports and studies can be found in the Technical Library.

  • Wetland Restoration Site Preparation ReportSite Prep Study Diagram (cropped) A site preparation study involving 50 plots took place at Coyote Prairie from 2005 to 2007. All treatment types converged with regard to community structure after three years. Two native bunchgrasses, Deschamspia cespitoza and Agrostis exarata, dominated the communities. A tradeoff between native percent cover and diversity became apparent: The sites reached half the native species richness of the reference sites (Pfeifer-Meister et al. 2007). Planting other native species earlier than the competitive bunchgrasses could alleviate the priority effects. It is also worth noting that native richness and exotic richness were similar in the reference sites, while the experimental plots were largely devoid of exotic species. Below are the treatments and their effects on the seed bank.
    • Solarization (plastic cover): Heavily reduced when used with herbicide
    • Herbicide: Reduced by Spring and Fall treatments; July treatment ineffective
    • Thermal (surface burn): Superficial; could be effective right after germination
    • Tilling: Ineffective
      A retroactive study examined seven restoration sites, one of which is Coyote Prairie, and three high quality reference sites to establish baseline data. While the communities of the restoration sites varied widely due to different treatments, the exotic species were consistent across the references. Both solarization and sod removal had low productivity compared to the references, and the study confirmed the tradeoff between native percent cover and diversity on a larger scale. - Treatment       Richness / Diversity   % cover      Biomass                    Soil Nutrients Solarization      low                              high            mostly grass              comparable to references Sod Removal   similar to references     low             majority in forbs        fewest nutrients
  • CoyotePlotsThis report builds on the Site Preparation Study to provide more insights into wetland prairie restoration. Key findings included:
    • Decreasing Deschampsia cespitosa in the seed mix in favor of native annual plants would improve native diversity.
    • A native diversity threshold exists that once reached prohibits invasive plant establishment.
    • Burning is the best restoration tool because it varies with microtopography and hydrology, creating more microhabitats.
    • Haying is preferable when burning is impossible because like burning it opens up colonization space for natives.
    • Mowing and grazing are poor choices: Mowing promotes exotic species and low diversity while grazing stimulates growth of Deschampsia cespitosa.
  • Microtopography Study ELP 2012    Project Website  

    Abstract

    Wet prairies provide numerous ecosystem services and habitat for native plant species. This study examines the relationship between microtopographic variation and plant diversity in six restored and remnant wet prairies in the West Eugene Wetlands to aid future restoration projects. It was predicted that variation in elevation is influential in determining native plant community composition. Along transects within previously established macroplots, soil surface elevation and water depth were measured and percent cover of grasses, forbs, and non-forbs, and measured vegetation and litter height were determined. A linear regression was performed comparing native species richness to the topographic coefficient of variation, which yielded an R2 value of 0.43 and a p-value of 0.16. Although these results are not statistically significant, they demonstrate a meaningful correlation between native plant richness and the coefficient of variation of topography. Further observations additionally suggest that this relationship is present. We suggest further research to determine significant results and suggest the integration of the restoration of microtopography into wetland management.