Dissertations and Theses @ UNI


Open Access Thesis


Prairie restoration--Iowa--Cedar Falls Region; Species diversity--Iowa--Cedar Falls Region; Forbs--Variation;


Plant species diversity in reconstructed prairies is extremely low when compared to that of prairie remnants. In this experiment I am testing the feasibility of increasing the abundance of native forbs in a reconstructed prairie using an incremental approach. The site chosen for this experiment is one that consists of five species of thirty-year old prairie grasses along with 23 species of native prairie forbs that were overseeded in 1999.

I hypothesized that forb diversity could be increased in an established grassland using an incremental approach, and that mowing would amplify the success of the planting. To test these ideas I overseeded 10 species of native forbs into 18, 12m x 15m experimental plots at a rate of250 seeds/m2• Each plot was then randomly assigned one of three mowing treatments: control, infrequently mowed, and frequently mowed, which were carried out for two consecutive growing seasons. I assessed the effects of the different mowing treatments on both the new species I seeded in 2003, the adult forbs that were seeded in 1999, as well as, the effects on the overall plant community.

While mowing did significantly increase the amount of light reaching the soil surface (p=0.02), and reduce the amount of accumulated leaf litter (p

Mowing also had significant effects on the established plant community. Mowing significantly (p

The overall plant community changed greatly during the experimental period, but the changes were not due to the mowing treatments. Species richness increased in all the plots from approximately 0.5 species/m2 in 2003 to nearly one species/m2 by 2005. The Shannon diversity index also increased from 1.8 in 2003 to 2.15 in 2005.

Based on the results of this study, I have concluded that it is possible to add forb diversity to a reconstructed prairie using an incremental approach (seven new forb species became established at the site during this experiment), but mowing may not be necessary during the second incremental seeding. The increase in species richness achieved here proves this method is effective for making prairie reconstructions more similar to the actual tallgrass prairie.

Year of Submission


Degree Name

Master of Science


Department of Biology


Tallgrass Prairie Center

First Advisor

Laura L. Jackson, Chair

Date Original


Object Description

1 PDF file (viii, 143 pages)



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