Thesis (D. Min.)--Trinity Evangelical Divinity School, 1997. / Abstract. Includes bibliographical references (leaves 136-140).

Thesis (M.S.)--Oregon State University, 1996. / Typescript (photocopy). Includes bibliographical references (leaves 229-241). Also available online.

Thesis (M. Sc.)--Carleton University, 1996. / Also available in electronic format on the Internet.

No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Historically, the tallgrass prairie (TGP) was the largest ecosystem in North America, but today only about 10-15% of the original extent exists today. Some areas have experienced more extreme loss, for example in the state of Illinois less than 0.01% of high-quality native tallgrass prairie remains. Non-native invasive species are a recent phenomenon that threatens the integrity of surviving TGP communities. Ecotypes of dominant C4 grasses are the basis of numerous cultivars, many of which are utilized in prairie restorations. In this study, the effects of three invasive species (Bromus inermis, Schedonorus phoenix, and Poa pratensis) on two lowland (`Alamo' and `Kanlow') and three upland (`Blackwell', `Cave in Rock', and `Trailblazer') cultivars of the dominant C4 grass Panicum virgatum were tested. Two simple pair-wise greenhouse experiments were established in which cultivars were sown as a monoculture or as a mixture of the cultivars with one of three invasive species. Pots were subjected to one of two water treatments with three replicates of each treatment combination. Response variables (height, number of leaves, tiller density, and biomass) and resources (soil moisture, soil pH, soil electrical conductivity, and light intensity) were measured. The greenhouse studies showed that response variables were affected by the presence of invasive species and that the time of growth affected resource levels. Resources are allocated to different areas (i.e growth and reproduction) when competition and stress are implemented on the dominant species. This study was the first to experimentally test for the presence of the physiological stress marker, trigonelline, in a prairie grass. Trigonelline was highest in upland cultivars under low moisture and highest in lowland cultivars under low moisture treatments. The results of these greenhouse studies suggest that invasive species may differentially affect cultivars of Panicum virgatum that may be sown in a prairie restoration. Performance of the P. virgatum cultivars was dependent on the timing of growth, the pot size, the invasive species, as well as soil moisture level. Therefore, when choosing a cultivar source for restoration, resources (i.e. soil moisture) should be looked into to maximize the output of the cultivar.

Ecological restoration aims to augment and steer the composition and contribution of propagules for community regeneration in degraded environments. Three studies were conducted to elucidate the role of regeneration dynamics and dominant species on community assembly during tallgrass prairie restoration. In the first study, patterns in the abundance, richness, and diversity of seed and bud banks were quantified across an 11-year chronosequence of restored prairies and in prairie remnants to elucidate the degree to which the germinable seed bank, emerged seedlings, belowground buds, and emerged ramets were related to community regeneration. There were no directional patterns in the abundance, richness, or diversity of the germinable seed bank across the chronosequence. Emerged seedling abundance of sown species decreased during restoration, whereas richness and diversity of all emerged seedlings and non-sown emerged seedling species decreased across the chronosequence. Conversely, abundance and richness of belowground buds increased with restoration age and belowground bud diversity of sown species increased across the chronosequence. Numbers of emerged ramets also increased across the chronosequence and was driven primarily by the number of graminoid ramets. There were no temporal changes in abundance and richness of sown and non-sown emerged ramets, but diversity of sown emerged ramets increased across the chronosequence. This study demonstrates that after initial seeding, plant community structure in restored prairies increasingly reflects the composition of the bud bank. In the second study, abundance and richness of ramets, emerged seedlings, seed rain, and the soil seed bank were measured in a restoration experiment consisting of a split plot design with population source of dominant grasses (cultivar vs. local ecotype) and sown subordinate species (three unique pools of non-dominant species) as the subplot factor, respectively. Different sown species pools were included to assess whether any observed differences in propagule abundance or richness between the dominant species sources was generalizable across varying interspecific interactions. Abundance of emerged ramets was similar between communities sown with cultivar and local ecotypes of the dominant grasses but differed among sown species pools in prairie restored with cultivars but not local ecotypes. Number of emerged seedlings also differed among species pools, but only in communities sown with local ecotypes of the dominant grasses. There was also higher seedling emergence in communities sown with local ecotypes relative to cultivars of the dominant grasses in one species pool. Richness of the seed rain was influenced by an interaction between dominant grass population source and sown species pool, resulting from (1) higher richness in prairie restored with local ecotypes than cultivars of the native grasses in one species pool and (2) differences in richness among species pools that occurred only in prairie restored with the local ecotype grass source. Abundance and richness of the seed bank was not affected dominant grass population source. This study addressed a poorly understood potential effect of using cultivars in ecological restoration, specifically on the abundance and supply of propagules for community assembly. These results suggest that if both local ecotype and cultivar sources are available for restoration, using local ecotypes could result in more seedling germination and richness in the seed rain. One of the central concepts of ecology is to understand the processes that influence species diversity, and how the resulting diversity affects ecosystem functioning. Diversity has been hypothesized to be responsible for long-term community stability, contrasted by the idea that dominant species regulate temporal stability (mass ratio hypothesis). In the third study, community metrics (total plant cover, forb cover, C4 grass cover, richness, and diversity) were measured in a restoration experiment consisting of a split plot design with sown dominant grasses (Andropogon gerardii, Schizachyrium scoparium, and Sorghastrum nutans) and subordinate species (three unique pools of non-dominant species) as the subplot factor, with treatment (control vs. suppression of dominant grasses) as the sub-subplot factor, respectively. Dominant grass suppression had little effect on forb cover, richness, and diversity, but influenced total and C4 grass cover. Propagule addition increased community richness and diversity in year of sowing and year after sowing, but contributed little to total cover. Dominant grass suppression had an effect on new species recruitment in one of two species pools, with suppression of all dominant grasses having the greatest influence on total cover and richness of new species. These results suggest that dominant species collectively are responsible for modulating stable species composition during community assembly and can act as a biotic filter to the recruitment of new species, but diverse subordinate species assemblages are more important for temporal stability.

Restoration of resilient plant communities in response to environmental degradation is a critical task, and a changing climate necessitates the introduction of plant communities adapted to anticipated future conditions. Ecotypes of dominant species can affect associated organisms as well as ecosystem function. The extent of ecotypic variation in dominant tallgrass prairie species and the consequences of this variation for ecosystem functioning were studied by manipulating two potential drivers of plant community dynamics: climate and the soil microbial community. Climate was manipulated indirectly through the use of reciprocal restorations across a rainfall gradient where regional sources of dominant grasses Andropogon gerardii and Sorghastrum nutans were seeded with 8 other native species that occur in tallgrass prairie. Four dominant grass sources (originating from central Kansas [CKS], eastern Kansas [EKS], southern Illinois [SIL], or a mixture of these) were reciprocally planted within four sites that occurred across a precipitation gradient in western KS (Colby, KS), CKS (Hays, KS), EKS (Manhattan, KS) and SIL (Carbondale, IL). The three grass sources and mixture of sources were sown into plots according to a randomized complete block design at each sites (n=16, 4 plots / block at each site). Aboveground net primary productivity (ANPP) was measured at the end of the 2010 and 2011 growing season at each site. In 2010, total ANPP declined from western to eastern Kansas, but increased across the geographic gradient in 2011. The dominant grasses did not comprise the majority of community ANPP in WKS, CKS or SIL in either year but did contribute most to total ANPP at the EKS site in 2011. In 2010, volunteer forbs comprised the largest proportion of ANPP in WKS, whereas and in both years planted forbs comprised the largest proportion of ANPP in SIL. Ecotypic variation in ANPP of A. gerardii was not evident, but Sorghastrum nutans ANPP exhibited a site by source effect in 2010 that did not suggest a home site advantage. Variation in the competitive environment at each site may have masked ecotypic variation during community assembly. Further, ANPP responses suggest that grasslands in early stages of establishment may respond more stochastically to climatic variation than established grasslands. Longer term studies will clarify whether ecotypes of dominant prairie grasses affect ecosystem function or community trajectories differently during restoration. Ecotypes of dominant species may support different soil microflora, potentially resulting in plant-soil feedback. A second experiment tested for local adaptation of prairie plant assemblages to their soil microbial community. Native plant assemblages from Kansas and Illinois were tested for local adaptation to their `home' soil by reciprocally crossing soil and plant source in a greenhouse experiment. Seeds and soil were obtained from two remnant prairies, one in eastern Kansas and one in central Illinois, with similar species composition but differing climate. Seeds of four species (Andropogon gerardii, Elymus canadensis, Lespedeza capitata, Oligoneuron rigidum) common to both locations were collected, germinated, and transferred to pots to create 4-species assemblages from each region. Non-prairie (NP) soil from the edge of an Illinois agricultural field was also included as an inoculum treatment to increase relevance to restoration. Kansas and Illinois plant assemblages were subjected to a fully factorial combination of soil inocula [with associated microbial communities] (3 sources: KS, IL, NP) and soil sterilization treatment (sterilized or live). Plants were harvested after 20 weeks and soil was analyzed for microbial composition using phospholipid fatty acid (PLFA) markers. Soil sources had different nutrient concentrations and sterilization resulted in a flush of NH4+, which complicated detection of soil microbial effects. However, plant sources did exhibit variation in productivity responses to soil sources, with Kansas plants more responsive to live soil sources than Illinois plants. Despite confounding variation in soil fertility, soil inoculation was successful at manipulating soil microbial communities, and plant sources responded differently to soil sources. Consideration of feedback between soil and plants may be a missing link in steering restoration trajectories.

Tallgrass prairie in North America has been highly reduced and degraded by human activity (e.g. agriculture) and now human facilitated restoration is necessary to preserve and reestablish the biodiversity, structure and function of this system. In historical tallgrass prairie large ungulates (e.g. Bison bison) were keystone species that regulated many ecosystem properties and functions. Today, restored prairie often lacks these historical ungulates and white-tailed deer (Odocoileus virginianus) have largely assumed the role of dominant ungulates in small, tallgrass prairie restorations. Little is known about how white-tailed deer affect the development of plant communities and ecosystem function during the onset of prairie restoration. In June 2012 an agricultural field was restored to native prairie species in Konza Prairie Biological Station (KPBS) near Manhattan, KS. Immediately following seeding, experimental plots were established and fences were constructed in half of the plots to excluded white-tailed deer. From 2012 to 2013 deer browse of forbs, aboveground biomass (total, sown forbs, sown grasses, volunteer forbs and volunteer grasses), light availability at the soil surface, soil nutrients, and plant community composition were measure inside and outside of exclosures. The first year of this study occurred during a severe drought which diminished in year two, presenting the opportunity to examine the interaction of climate and deer browse on restoration. In plots where deer had access, the percentage of forbs browsed ranged from 1.3 to 10.5%. The effect of deer browsing on aboveground biomass varied across years for each category of biomass. Total biomass appeared to be regulated more strongly by deer than climate, as unbrowsed plots produced similar biomass in each year despite major climatic variation, while browsed plots did not follow this trend. Across all sampling periods, deer browsing increased light availability by 20%. In year two inorganic N was 19% lower in browsed plots, though potential net N mineralization did not vary between treatments. Plant communities were significantly different between years and, between browsed and unbrowsed plots as time and browsing affected community composition, diversity and richness. Deer browsing increased diversity and richness by 24% and 22% respectively. Community composition was most greatly affected by browsing in year one corresponding to the highest rates of browsing and greatest differences in aboveground biomass. These results indicate that deer can have substantial effects on the initial establishment of prairie communities as well as resource availability from the onset of restoration.

Wide-scale conversion of tallgrass prairie to row-crop agriculture has spurred restoration of this endangered ecosystem. At the onset of restoration, a matrix of native plant species is sown into former crop field and includes warm-season (C4) grasses, cool-season (C3) grasses, legumes, and a large variety of herbaceous forbs. Increased demand for native seed due to a greater number of areas targeted for restoration has increased use of C4 grass cultivars by restoration practitioners. Cultivars are selectively bred to display traits such as increased productivity and digestibility, thus highlighting their original use in rangelands of the Great Plains. C4 grasses have a mutualistic relationship with arbuscular mycorrhizal fungi (AMF). In remnant tallgrass prairie, AMF can increase C4 plant uptake of belowground resources (e.g., water, soil P) by increasing root surface area. It is unknown if AMF colonization varies between seed source (cultivar or non-cultivar) of C4 grasses used in restoration and if this further affects plant biomass. Intraspecific variation in AMF colonization between two dominant warm-season prairie grasses was tested in two established prairie restoration experiments, both having plots seeded with either C4 cultivars or non-cultivars. To test for effects of seed source and AMF colonization on plant biomass, a greenhouse experiment was designed using two source populations (cultivar and non-cultivar) of two species (Andropogon gerardii Vitman and Sorghastrum nutans (L.) Nash) and soil collected at each field restoration (Kansas and Illinois). To suppress activity and colonization of AMF, a fungicide (Allban Flo: Thiophanate Methyl) was applied to half of the containers. Warm-season (C4) grass cultivars had greater or equivalent biomass production than non-cultivars at the onset of field restoration and also in the greenhouse. Furthermore, cultivars generally had less or equivalent root colonization by AMF and dependence on fungicide-free soil was greater in cultivars to retain increased accrual of biomass. It was, however, not possible to determine the role of AMF in plant biomass production as fungicide did not successfully reduce AMF root colonization in cultivars or non-cultivars, with one exception. It is critical that an effective AMF-suppression treatment be established in these types of studies. Future experiments should validate supposed effectiveness of the newly-recommended fungicide (Topsin-M) in population sources of warm-season prairie grasses and also apply it to the soil at time of planting in greenhouse studies. In the field sites, adjacent soil cultivation may have contributed to greater AMF biomass more so than surrounding remnant prairie. Future research identifying species composition of AMF at these sites is necessary to clarify differences in biomass. Despite greater plant biomass in cultivars, soil nutrient availability remained equivalent between source populations in general. Available N and P were not less in soils grown with cultivars, however soil inorganic N was inversely related to root length colonized by AMF, suggesting a role of AMF in N transfer from soil to plant. Soil P was not different between source populations likely due to legacy effects of agricultural fertilization, thus limiting a well known benefit of AMF symbiosis, at least at the onset of restoration. Non-target effects of fungicide application were observed (e.g., changes in available N) and effectiveness of AMF suppression was questionable. Fungicide lowered pH and increased N availability in soil as indicated by main effects of application and a positive relationship between pH and inorganic N across species. Fungicide application either 1) decreased N uptake by soil microorganisms (possibly including AMF) or 2) increased competition for adsorption sites and/or solubility of total inorganic N as pH changed, thus making this nutrient more available in the soil solution. Future examination quantifying indirect effects of fungicide application on soil chemistry should also be considered to better elucidate role of AMF in plant growth and soil nutrient availability between cultivars and non-cultivars of warm-season grasses used in tallgrass prairie restoration.