Doctor of Philosophy / Department of Agronomy / Stephen J. Thien / Range and Training Land Assessment (RTLA) and Land Rehabilitation and Maintenance (LRAM) are key components of The United States Army's Integrated Training Area Management (ITAM) Program, which outlines its commitment to support the sustainable use of military training lands. The primary purpose of the RTLA Program is to provide information and recommendations regarding the condition of training lands to range managers for scheduling of training areas and monitoring the effectiveness of rehabilitation projects. The goal of the LRAM component of ITAM is to reduce the long-term impacts of training on installations through the implementation of improvements to vegetation cover and repairs to landscape damage in disturbed areas. Fort Riley Military Installation, located in the largest remaining expanse of tallgrass prairie in the Flint Hills of northeastern Kansas, is a major training reservation, with seventy percent of its 40,434 ha used for mechanized maneuvers. A randomized complete block design composed of M1A1 tank traffic in a figure-eight pattern during wet and dry soil conditions was established in each of two soil types, a silty clay loam and a silt loam, and recovery of physical, chemical, and biological indicator variables was monitored from 2005 through 2007. In a second study, the effectiveness of LRAM procedures, including leveling, mulching, and reseeding, was evaluated following wheeled vehicle disturbance. The goals of this study were to identify disturbance indicators appropriate for assessing soil quality and, based on the status of these indicators, develop a method for modeling the stage and rate of ecological degradation and potential response to remediation. Disturbance increased significantly during wet compared to dry soil conditions, for increased traffic intensity, and for curve compared to straight-a-way areas in both soil types. The greatest impacts were on above and below ground community structure, providing an effective bioindicator of ecosystem health for military training land managers. Remediation of wheeled vehicle disturbance with leveling and mulching, but not reseeding, increased total vegetation production. The tallgrass prairie typically is considered to be among the most resilient of military training lands, but resiliency is dependent upon soil type and training conditions, and may require longer periods of recovery than previously thought.

Afin d’appréhender l’impact des dépôts d’azote atmosphérique sur les écosystèmes,nous nous sommes intéressés à un écosystème d’intérêt patrimonial : les prairies acides duViolion caninae. Au sein de ces prairies, les objectifs étaient de (i) quantifier les variationsfloristiques temporelles et spatiales le long du domaine atlantique français et de déterminer siles variables de dépôts d’azote et du climat expliquaient ces patrons, (ii) comprendre lesprocessus mis en jeu lors de l’enrichissement en azote au niveau de la végétation et du sol, et(iii) examiner les moyens potentiels de conservation et de restauration.L’étude temporelle et spatiale des prairies acides a permis de mettre en évidence deschangements de composition à l’échelle locale du type de communautés mais également àl’échelle nationale du domaine atlantique français. A l’échelle locale et nationale, ceschangements ont pu être reliés à des changements climatiques d’augmentation de latempérature annuelle moyenne et de diminution de la disponibilité en eau du sol. Toutefois àl’échelle locale, les plus forts changements de végétation ont été perçus pour les sites soumiségalement aux plus forts dépôts chroniques d’azote depuis les 25 dernières années. Ceschangements de composition se sont produits au détriment des espèces de petites tailles, tellesque des dicotylédones, alors que les Poacées généralistes se sont maintenues en dominant lecouvert végétal. Ces changements sont visibles dès 10-15 kg N ha-1 an-1, déterminé comme lacharge critique d’azote pour les prairies acides.L’approche expérimentale a permis de souligner les processus mis en jeu dans ceshabitats acides lors d’un apport d’azote. Notamment, l’enrichissement en azote n’entraineraitpas de compétition pour la lumière au sein de la végétation. Ce type de milieu, principalementdéfini par son caractère oligotrophe et sa faible capacité à neutraliser l’acidité du sol,semblerait donc essentiellement affecté par des mécanismes de toxicité de l’ammonium voired’acidification du milieu à long terme.Enfin, les moyens de restauration étudiés ont montré la difficulté de conserver et derestaurer de tels habitats potentiellement affectés par les dépôts d’azote. En effet, l’utilisationde fauches répétées avec exportation de la biomasse a montré son inutilité dans un systèmequi n’est pas influencé par la compétition pour la lumière. De même, l’étude des banques degraines a montré que ce pool d’espèces ne pouvait pas représenter le seul moyen deconservation des espèces caractéristiques. Ces résultats révèlent l’importance de conserver lesprairies acides existantes, principalement dans des sites soumis à de faibles dépôts ambiants. / To assess the impact of atmospheric nitrogen deposition on ecosystems, we werefocused on a patrimonial interest ecosystem: acid grasslands of Violion caninae. Within thesegrasslands, we aimed to (i) characterise temporal and spatial variation in plant speciescomposition along the French Atlantic domain and determine if nitrogen deposition andclimate variables could explain these patterns, (ii) understand processes underlined bynitrogen addition on vegetation and soil, and (iii) examine the potential conservation andrestoration ways.Temporal and spatial approach of acid grasslands brought to light changes in speciescomposition at local scale of community type but also at the national French Atlantic domainscale. At both local and national scale, these changes were linked to climate change withincrease of mean annual temperature and decrease of soil water availability. However at localscale, the most changes in species composition were experienced on sites with climate changeand also the highest chronic nitrogen deposition since the last 25 years. These changes inspecies composition occurred at the expense of short stature species like forbs whereasgrasses species were persistent and dominated vegetation. These changes are visible from 10-15 kg N ha-1 an-1, determined as the critical load for nitrogen in acid grasslands.The experiment allowed to highlight processes underlined in acid grasslands afternitrogen addition. In particular, nitrogen enrichment did not lead to light competition invegetation. These grasslands, mainly defined by poor-nutrient and low capacity to bufferacidity in soil, were essentially affected by ammonium toxicity or even acidification on thelong range.Finally, the study of conservation ways showed the difficulty to conserve and restorethe grasslands affected by nitrogen deposition. Indeed, more frequent cuttings with biomassremoval were useless in a system not influenced by light competition within vegetation. Thestudy of seed banks showed also that conservation ways could not be based just on seed banksto maintain characteristic species. These results highlight the importance to conserve theexisting acid grasslands, mostly in region with low ambient nitrogen deposition.

Edwin Fissinger (1920-1990) was a conductor and prolific choral composer. His compositional techniques, settings of text, jazz-influenced harmonies, and melodic propulsion fulfill an important role in each of his compositions. In the eight choral cycles he composed, Fissinger unified each cycle through thematic and textual elements. Although this resulted in a logical progression of poetry and music, Fissinger's final choral cycle, Prairie Scenes, was not published as he intended. Rather, individual selections from the cycle were published by two different publishing houses, out of sequence, and sixteen years apart. Consequently, the eight pieces are not currently performed together. Today's choral conductors, singers, and audience do not fully appreciate the value of this choral cycle and cannot understand its intended context. It is necessary to provide an in-depth investigation of the original eight-piece work Prairie Scenes: A Choral Cycle to place the appropriate organizational set together. This study illustrates the importance of the unification of Fissinger's Prairie Scenes: A Choral Cycle through a study of the poetry, the thematic material as it relates to the natural elements of the prairies, the manuscripts, and interviews with Fissinger's publishers and colleagues. An examination of Fissinger's compositional technique to convey the meaning of the text reveals a clear link between Prairie Scenes and the North Dakota prairies and its seasons. A description of the development of the choral cycle throughout music history and a biography of Edwin Fissinger and his compositional style are also included.

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Ecological niche models (ENMs) were created for White-tailed and Black-tailed prairie dogs and projected into the Last Interglacial (LI), the Last Glacial Maximum (LGM), and mid-Holocene (mid-H) to discern possible past suitable habitat for both species. Additionally, ENMs were projected into the future year 2070 representative concentration pathways (RCPs) 2.6 and 8.5 to discern how climate change may affect future habitat suitability. Kernel density estimations, minimum convex polygons, and median distribution centers of White-tailed and Black-tailed occurrence records were examined between time-periods to discern the effects of anthropogenic westward expansion on both species’ distributions. Current ENMs were constructed from commonly used bioclimatic variables and non-traditional variables (including EPA level III Ecoregions) for White-tailed and Black-tailed prairie dogs for variable comparison performance in ENMs. Results indicate that both species respond to climate change and each occupy distinct ecological niches. Biogeographical changes coincident with westward expansion remain unknown.

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Fire suppression, combined with lack of forest thinning and short-rotation, monodominant management, has drastically altered the landscape in the southeastern U.S., leading to the loss of open pine ecosystems and associated avian species. Management of open pine ecosystems is a common practice; yet, there remains uncertainty regarding how vegetation structure impacts priority species. Using empirical data, I assessed changes in species abundance and associated vegetation characteristics before and after management. I also sought to identify vegetation characteristics that influence home range establishment and microhabitat selection of Bachman’s Sparrows. Priority species were negatively associated with hardwood midstory and abundance per site increased following management. Home range establishment of Bachman’s Sparrows was influenced by disturbance, canopy cover, and slope, while microhabitat selection was influenced by pine basal area, available perching options, vegetation density, and herbaceous groundcover. Understanding how vegetation structure impacts priority species may be helpful in guiding conservation and management efforts.

The primary goal of this research is to evaluate and identify proper calibration approaches, skillful hydrological models, and suitable weather forecast inputs to improve the accuracy and reliability of hydrological forecasting in different types of watersheds. The research started by formulating an approach that examined single- and multi-site, and single- and multi-objective optimization methods for calibrating an event-based hydrological model to improve flood prediction in a semi-urban catchment. Then it assessed whether reservoir inflow in a large complex watershed could be accurately and reliably forecasted by simple lumped, medium-level distributed, or advanced land-surface based hydrological models. Then it is followed by a comparison of multiple combinations of hydrological models and weather forecast inputs to identify the best possible model-input integration for an enhanced short-range flood forecasting in a semi-urban catchment. In the end, Numerical Weather Predictions (NWPs) with different spatial and temporal resolutions were evaluated across Canada’s varied geographical environments to find candidate precipitation input products for improved flood forecasting. Results indicated that aggregating the objective functions across multiple sites into a single objective function provided better representative parameter sets of a semi-distributed hydrological model for an enhanced peak flow simulation. Proficient lumped hydrological models with proper forecast inputs appeared to show better hydrological forecast performance than distributed and land-surface models in two distinct watersheds. For example, forcing the simple lumped model (SACSMA) with bias-corrected ensemble inputs offered a reliable reservoir inflow forecast in a sizeable complex Prairie watershed; and a combination of the lumped model (MACHBV) with the high-resolution weather forecast input (HRDPS) provided skillful and economically viable short-term flood forecasts in a small semi-urban catchment. The comprehensive verification has identified low-resolution NWPs (GEFSv2 and GFS) over Western and Central parts of Canada and high-resolution NWPs (HRRR and HRDPS) in Southern Ontario regions that have a promising potential for forecasting the timing, intensity, and volume of floods. / Thesis / Doctor of Philosophy (PhD) / Accurate hydrological models and inputs play essential roles in creating a successful flood forecasting and early warning system. The main objective of this research is to identify adequately calibrated hydrological models and skillful weather forecast inputs to improve the accuracy of hydrological forecasting in various watershed landscapes. The key contributions include: (1) A finding that a combination of efficient optimization tools with a series of calibration steps is essential in obtaining representative parameters sets of hydrological models; (2) Simple lumped hydrological models, if used appropriately, can provide accurate and reliable hydrological forecasts in different watershed types, besides being computationally efficient; and (3) Candidate weather forecast products identified in Canada’s diverse geographical regions can be used as inputs to hydrological models for improved flood forecasting. The findings from this thesis are expected to benefit hydrological forecasting centers and researchers working on model and input improvements.