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Emergence And Mortality Of Native Prairie Forbs Seeded Into An Established Stand Of Grasses, Dave Williams

Dissertations and Theses @ UNI

Thousands of hectares of warm-season grass plantings in Iowa have few to no native forbs. Diversifying these species poor plant communities with native prairie forbs could result in increased resistance to climatic extremes, increased biodiversity, reduced noxious "weedy" plant invasion, and reduced geographic isolation between existing native prairie remnants.

I hypothesized that frequent mowing in the first one or two years after broadcasting forb seed into an established stand of warm-season grasses can increase forb emergence and reduce forb mortality. I further hypothesized that fall seeded forbs would establish better that those seeded in spring.

To test my hypothesis, I …

Organophosphorous Insecticide Contamination In Streams: Insects As Bioindicators, Brian M. Andersen

Dissertations and Theses @ UNI

Organophosphorous (OP) insecticides are widely used around the world to control pests. These insecticides can enter streams and rivers and impact nontarget aquatic organisms by inhibiting acetylcholinesterase (ACE), a nervous system enzyme necessary for normal behavior and survival. However, these contamination events are usually brief and often missed by chemical analyses attempting to detect OP insecticides. Although ACE activity has been used as a bioindicator of OP insecticide exposure in humans and wildlife for many years, few studies have investigated using aquatic insect ACE activity as a potential bioindicator of OP insecticide contamination in streams. This study used the mayfly …

Monitoring Of Prairie Bushclover (Lespedeza Leptostachya) In South-Central Iowa, Paul J. Bockenstedt

Dissertations and Theses @ UNI

Prairie bushclover Lespedeza leptostachya is listed as threatened by both the U.S. Fish and Wildlife Service and the State of Iowa. Found within the tallgrass prairie region only in four midwestern states, prairie bushclover is considered a midwestern endemic. The federal recovery plan includes the goal to stabilize populations through proper management techniques and long-term management plans.

In 1989, three permanent plots were established for long-term monitoring at Madison Prairie in Clarke County, Iowa to examine population trends under the influences of fire and grazing. Fifty prairie bushclover plants were randomly selected within the three plots and square meter sampling …

The Use Of Aflp To Detect Genetic Differentiation Within And Among Populations Of Two Prairie Plant Species: Panicum Virgatum And Coreopsis Palmata, Christopher Andrew Hilker

Dissertations and Theses @ UNI

The degree of genetic diversity within any species is crucial to its survival with respect to environmental stresses and its ability to adapt. As native Iowa prairie plant populations continues to diminish, genetic diversity within the state becomes crucially important for restoration, reconstruction, and conservation efforts. This study seeks to determine the degree of genetic variation within native Iowa populations of Panicum virgatum (switchgrass) and Coreopsis palmata (prairie coreopsis, tickseed, prairie tickseed). Plants were obtained directly from the tallgrass prairie, from native seed plantings, and from greenhouse grown cultivated varieties (switchgrass). Amplified Fragment Length Polymorphisms (AFLP) provided genetic fingerprints of …