Thesis (Ph. D.)--University of Kentucky, 2005. / Includes bibliographical references (p. 203-220). Also available in PDF format via the Internet.

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

Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Mar. 4, 2010). Includes bibliographical references (p. 65-72).

The population of central Texas is increasing rapidly, and urbanization and suburban development continue amid projections of unprecedented growth to come. How is this affecting the expanses of rich agricultural land and remaining scraps of Blackland Prairie upon which the agricultural industry of east central Texas was built? State Highway 130 is partially complete – providing an urban-area bypass intended to alleviate traffic on I35 between San Marcos and Georgetown. In view of the building of this new transit and development corridor to the east of I35, on the eastern edge of Austin, what can be done to preserve agriculture and native prairie on Austin’s urban fringe? In this PR, I examine this question in terms of two essential components: growth management and land conservation. There are numerous studies on the structures and efficacies of growth management tools and of land conservation strategies, but there is little discussion of the role of growth management in relation specifically to urban and urban-fringe agriculture. I begin with a literature review, surveying the current state of study and practice with regard to growth management and open space & agricultural land conservation. This is followed by a case study of state-level open space conservation policy in Georgia, from which I draw lessons relevant to my case. The next step is to frame the potential management and conservation policies presented win the literature review and case study within the context of local practices, thus narrowing the focus of analysis to the confines of my study area: an approximately 20-mile wide, 58-mile long corridor along a portion of SH130. To gauge the possibilities for management and conservation within the study area, I have produced a matrix of jurisdictions and policy options, and an inventory of vacant land. Using the matrix I analyze, on the one hand, the relevant legal codes available to each jurisdiction, and on the other hand, local attitudes toward growth and agriculture. The land inventory is a graphic presentation – through GIS mapping – of factors critical to the potential preservation of open space. The final operation is to sketch a larger proposal within which this study would fit as a preliminary step. Here I suggest an implementation plan, based on the Envision Central Texas model, and recommend directions for future research. / text

Optimal scale of study and scaling are fundamental to ecological research, and have been made easier with remotely sensed (RS) data. With access to RS data at multiple scales, it is important to identify how they compare and how effectively information at a specific scale will potentially transfer between scales. Therefore, my research compared the spatial, spectral, and temporal aspects of scale of RS data to study biophysical properties and spatio-temporal dynamics of the northern mixed prairie vegetation. I collected ground cover, dominant species, aboveground biomass, and leaf area index (LAI) from 41 sites and along 3 transects in the West Block of Grasslands National Park of Canada (GNPC; +49°, -107°) between June-July of 2006 and 2007. Narrowband (VIn) and broadband vegetation indices (VIb) were derived from RS data at multiple scales acquired through field spectroradiometry (1 m) and satellite imagery (10, 20, 30 m). VIs were upscaled from their native scales to coarser scales for spatial comparison, and time-series imagery at ~5-year intervals was used for temporal comparison. Results showed VIn, VIb, and LAI captured the spatial variation of plant biophysical properties along topographical gradients and their spatial scales ranged from 35-200 m. Among the scales compared, RS data at finer scales showed stronger ability than coarser scales to estimate ground vegetation. VIn were found to be better predictors than VIb in estimating LAI. Upscaling at all spatial scales showed similar weakening trends for LAI prediction using VIb, however spatial regression methods were necessary to minimize spatial effects in the RS data sets and to improve the prediction results. Multiple endmember spectral mixture analysis (MESMA) successfully captured the spatial heterogeneity of vegetation and effective modeling of sub-pixel spectral variability to produce improved vegetation maps. However, the efficiency of spectral unmixing was found to be highly dependent on the identification of optimal type and number of region-specific endmembers, and comparison of spectral unmixing on imagery at different scales showed spectral resolution to be important over spatial resolution. With the development of a comprehensive endmember library, MESMA may be used as a standard tool for identifying spatio-temporal changes in time-series imagery. Climatic variables were found to affect the success of unmixing, with lower success for years of climatic extremes. Change-detection analysis showed the success of biodiversity conservation practices of GNPC since establishment of the park and suggests that its management strategies are effective in maintaining vegetation heterogeneity in the region. Overall, my research has advanced the understanding of RS of the northern mixed prairie vegetation, especially in the context of effects of scale and scaling. From an eco-management perspective, this research has provided cost- and time-effective methods for vegetation mapping and monitoring. Data and techniques tested in this study will be even more useful with hyperspectral imagery should they become available for the northern mixed prairie.

No description available.

The mixed-grass prairie region of southwestern Manitoba is a hotspot for many endangered grassland birds. This region has been degraded to less than a quarter of its historical amount of mixed-grass prairie. Remaining prairie is primarily used for livestock grazing. The objective of this study was to evaluate the contribution of sustainable land management practices, such as rotational grazing, in the conservation of this region. In 2008 and 2009, I compared the abundances of grassland birds on two grazing regimes, twice-over rotation and season-long, to ungrazed fields. Bird surveys were done during the breeding season and were conducted using 100-m fixed-radius point-count plots. I determined the effects of treatment, landscape and vegetation characteristics on songbird abundances using generalized linear mixed models. Grassland birds selected grazed pastures over ungrazed fields in both years, and species richness of obligate grassland birds was significantly greater (α = 0.10) on season-long than twice-over pastures (β = 0.419, p = 0.032, in 2008 and β = 0.502, p = 0.043 in 2009). Season-long grazing may actually benefit grassland bird communities by creating somewhat temporally stable areas of high use and low use within the pasture. However, nesting success studies and long-term monitoring are necessary to further understand how twice-over rotation grazing systems contribute to the conservation of grassland birds in southwestern Manitoba.

The Glenlea long-term study, located in Manitoba was established in 1992 to compare organic, conventional, no-input and restored prairie grass land management practices. Microbial biomass carbon (MBC), microbial metabolic quotient (qCO2), microbial biomass phosphorus, and microbial nitrous oxide quotient (qN2O) were measured to evaluate soil health. MBC and activity were higher in the forage-grain (MBC= 1613 µg-MBC/g-dry soil; qCO2= 0.75 mg CO2-C/g-dry soil/hr) rotation compared to the annual (MBC= 1124 µg-MBC/g-dry soil; qCO2= 0.60 mg CO2-C/g-dry soil/hr). The forage-grain organic system (1718 µg-MBC/g-dry soil) had the highest MBC compared to its conventional (1476 µg-MBC/g-dry soil) counterpart and behaved similarly to the restored grassland prairie (MBC= 1668 µg-MBC/g-dry soil; qCO2= 1.46 mg CO2-C/g-dry soil/hr). Rotation was significant (P<0.0001) for most variables, suggesting rotation has a strong influence on soil microbial characteristics. Agricultural management practices like perennial organic systems, mimic natural prairies and have the greatest capacity to sustain soil microbial life.

I investigated how orchid biology, floral morphology, and diversity of surrounding floral and pollinator communities affected reproductive success and hybridization of Cypripedium candidum and C. parviflorum. Floral dimensions, including pollinator exit routes were smallest in C. candidum, largest in C. parviflorum, with hybrids intermediate and overlapping with both. This pattern was mirrored in the number of insect visitors, fruit set, and seed set. Exit route size seemed to restrict potential pollinators to a subset of visiting insects, which is consistent with reports from other rewardless orchids. Overlap among orchid taxa in morphology, pollinators, flowering phenology, and spatial distribution, may affect the frequency and direction of pollen transfer and hybridization. The composition and abundance of co-flowering rewarding plants seems to be important for maintaining pollinators in orchid populations. Comparisons with orchid fruit set indicated that individual co-flowering species may be facilitators or competitors for pollinator attention, affecting orchid reproductive success.

Males of many species have elaborate phenotypes that are absent in females and that are thought to be the result of sexual selection. Sexual selection requires: (i) variance in male mating success, (ii) variation in male phenotype, and (iii) covariation between male mating success and male phenotype. Environmental conditions influence these factors, and management practices that alter environmental conditions have the potential to shape mating patterns and sexual selection. I investigated the hypothesis that the frequency of fire, used to manage tallgrass prairie, affects the mating patterns and process of sexual selection in the organisms breeding in managed prairies. I studied dickcissels (Spiza americana), a small songbird resident in tallgrass prairie. I first examined mating patterns and sexual selection in dickcissels independent of burning regime. I found variation among males in the number of mates attracted, in the number of offspring sired with each mate, and the offspring sired with the mates of other males. I found a positive association between social mates and siring success, but no evidence for an effect of breeding density or synchronous nesting on mating success. Male dimorphic traits, size, song, and plumage, showed between-individual variation but selection gradients were weak and often fluctuated between the years of study. I next examined patterns of mating success in plots burned on a variable schedule. I found little evidence that burning influenced either the mean or the variance in social mating success, paternity, or male phenotype. Burning regime also had no influence on sexual selection gradients with the single exception of selection on tarsus length. Temporal variation was more important for patterns of mating success and sexual selection gradients on male traits than was burning regime. The demography of dickcissels in the breeding season suggests, however, that habitat management on a larger scale may be more influential. My findings extend our understanding of sexual selection in birds and the effects of management on the factors required for sexual selection and the magnitude of selection.