Assessing factors mediating restoration outcomes of herbicide followed by native seeding in invaded tallgrass prairies

Mingione, Jessica Estela

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https://hdl.handle.net/2142/117833 Copy

Description

Title

Assessing factors mediating restoration outcomes of herbicide followed by native seeding in invaded tallgrass prairies

Author(s)

Mingione, Jessica Estela

Issue Date

2022-12-05

Director of Research (if dissertation) or Advisor (if thesis)

Miller, James R.

Committee Member(s)

• Fraterrigo, Jennifer M.
• Benson, Thomas J.

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• invasive
• tallgrass prairie, native plant restoration
• tall fescue
• herbicide
• grazing
• topography

Abstract

Temperate grasslands are globally one of the most imperiled ecosystems due to extensive conversion to other land uses and invasion of remaining grasslands by non-native plants. Invasive plants are typically controlled in degraded grasslands using herbicide followed by native seeding to restore native plant communities. Although degraded prairies within working landscapes are characterized by variable land use, disturbance, and landscape features, research evaluating how these factors mediate restoration outcomes is rare. I address these gaps by studying how land use and landscape variation relate to plant community dynamics in degraded prairies before and after restoration. Chapter 1 provides a review of approaches to prairie restoration and summarizes how land use and landscape features mediate resource availability and invasion. This review is followed by two studies conducted in the Grand River Grasslands, located in the eastern Great Plains between Iowa and Missouri. In Chapter 2, I evaluated plant community characteristics of restorations treated with herbicide followed by native seeding over eight years in tallgrass prairies invaded by tall fescue (Schedonorus arundinaceus). We compared 16 restorations seeded once between spring 2014 and 2021 to 3 high-diversity references and 2 invaded controls. Domestic cattle grazed six restorations and one control. The remaining sites were ungrazed. The species composition, herbaceous cover, and richness of seeded species of older restorations resembled high-diversity references more closely than recent restorations. However, grazed restorations did not resemble references as closely as ungrazed restorations. The similarities between older restorations and references indicate that herbicide followed by native seeding can restore native plant communities that reflect high-diversity references in invaded tallgrass prairies. In Chapter 3, I quantified the relationship among landscape features, patterns of tall fescue invasion, and restoration outcomes in degraded tallgrass prairies in the eastern Great Plains. First, I combined quadrat-level cover collected in July 2021 with data collected from 2011 to 2018 to examine the relationship between landscape features and the cover of native and exotic grasses in 18 sites. Tall fescue cover increased near roadsides and crop fields. Native grass cover increased farther from linear features. Native cover also increased and tall fescue cover decreased with slope steepness, especially under the intensive-early stocking regime that increased grazing pressure early in the growing season, compared to sites grazed with consistent pressure season-long. Then, I examined data collected from 2015-2018 in a subset of sites (n=7) treated with herbicide followed by native seeding. Post-treatment, tall fescue reductions were more pronounced near linear features and on flatter slopes. Native grass cover increased substantially near water features post-treatment. These results indicate that the treatment of roadsides and flatter slopes should be prioritized. These results highlight the importance of long-term monitoring and demonstrate that restoration outcomes vary with time-since-seeding, grazing regime, and landscape features. Considerations of these relationships can contribute to fine-tuning restoration efforts to optimize the restoration of native plant communities across the variable landscape of remaining tallgrass prairies.

Graduation Semester

2022-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Jessica Mingione

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