Date of Award

5-1-1981

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Biology

First Advisor

Dr. Thomas Bragg

Abstract

Ten eastern Nebraska tallgrass prairie remnants, varying in size from 1-18 ha, were evaluated for floristic composition at four times during the 1979 growing season. A total of 153 species were recorded of which seven dominated: Andropogon gerardii, A. scoparius, Bromus inermis, Ceanothus americanus, Heliopsis helianthodies, Poa pratensis, and Stipa spartea. Floristic composition, however, varied with respect to management, topography, season of evaluation, and prairie size. Frequent mowing reduced canopy cover of native species, such as Andropogon gerardii, by 21% while increasing that of non-native species, such as Bromus inermis, by 35%. In addition, frequently mowed sites contained a greater number of disturbance species (14 species), such as Conyza canadensis and Setaria glauca, than less frequently mowed sites (6 species). Canopy cover on sites mowed early in the summer averaged 54% higher for warm-season species and 26% lower for cool-season species than on sites mowed in late summer. Total vegetative cover, total grass cover, and total forb cover were lowest for hilltops and south-facing slopes although canopy cover of individual species varied with respect to topographic setting. Total vegetative cover and number of species recorded were highest in August evaluations; canopy cover of individual species varied throughout the growing season. A significant correlation was found between prairie size and Species Richness (P=0.02).

Comments

A Thesis Presented to the Department of Biology and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Master of Arts University of Nebraska at Omaha. Copyright 1981 Judith F. Boettcher.

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