Zugl.: Halle (Saale), Univ., Diss., 2008

Thesis (M.S.)--Ohio University, June, 2005. / Includes bibliographical references (p. 33-37)

Thesis (M.S.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Bruce D. Maxwell. Includes bibliographical references (leaves 114-130).

Thesis (M.S.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 33-37)

Thesis (M.S.)--University of Massachusetts Amherst, 2008. / Includes bibliographical references (p. 35-39).

No description available.

Background: Lespedeza cuneata is a perennial invasive legume native to Asia that is common across grasslands in the eastern half of the United States and parts of Canada. The competitive nature and limited palatability of L. cuneata for grazers in the tallgrass prairie has made it an undesirable and invasive weed. Objectives: This study was conducted to investigate an invasive species management plan for restored grasslands and prairie areas. Methods: Study plots (n=144) for experiment 1 (summer treatment) were established at Crab Orchard Wildlife Refuge in Jackson County Illinois in August of 2012 and were situated to contain infestations of the target species. Two herbicides, in five concentrations were applied in August of 2012. A native seed mix was added to a portion of the summer plots later, in February of 2013. These treatments were assessed in June and August of 2013 to determine herbicide effects on stem count and percent cover of L. cuneata, along with the composition and percent cover of other species present. Spring herbicide applications (n=18) for experiment 2 were established, assessed for L. cuneata cover and density, and treated with two herbicide treatments in May of 2013. Spring treatments were identical to existing plots and were re-assessed in August 2013 to determine species composition and the abundance of L. cuneata. Seed was not added to these plots. Analysis: Mixed Model analysis by site was performed to test the effect of herbicide and seeding treatments on L. cuneata for both experiments 1 &2. The summer plots were also tested for effects on other plant groups. A repeated measures PERMANOVA along with ANOSIM and PERMADISP was performed to assess community composition response to seeding and herbicide treatments in the summer plots. Results: Abundance of L. cuneata was reduced 67 to <90% following herbicide treatment in Experiments 1 and 2. There were no differences in the effectiveness of herbicide treatments in in experiment 1, sites 1 &3, and in experiment 2. Supplemental seeding in the summer plots did not reduce the abundance of L. cuneata consistently across sites. Conclusion: Considerable short-term control of the target species was achieved in both the summer and spring plots, providing a window of opportunity for the imposition of additional methods of control. However, data from the summer plots suggest recovery of L. cuneata some sites, indicating further control would be necessary, with potentially the addition of other control methods or site alterations.

Numerous studies have addressed the role of stream geomorphology on vegetation distribution. These studies have shown that channel morphology, including depositional and erosional processes, influence vegetation colonization. However, few studies have addressed the impact of vegetation on the geomorphic processes of streams. Vegetation has the ability to stabilize channel banks and alter stream hydrology and stream power. Little research has addressed the impact of invasive vegetation and its ability to change river channel processes. My research addresses the impact of the highly invasive Phalaris arundinacea and quantifies its influence on the stream channel form of the Sprague River, Oregon. I conducted field research that included root density and root strength surveys to determine the below ground influences of vegetation in terms of added bank cohesion provided by the invasive and two similar native species: Eleocharis palustris and Carex vesicaria. To ascertain differences between the species above ground characteristics and influences, I measured stem density and elasticity to calculate their roughness (Manning's n) and determine their potential impact on stream velocity. Finally, I used these vegetation characteristics to model stream velocity, water depth, and bed shear stress within the 2-D model MD-SWMS. Differences in root size were significant with C. vesicaria having the largest root diameters, largest root area ratio, and largest bank cohesion provided by roots. This was followed by the invasive and then E. palustris. E. palustris had the highest stem density, followed by C. vesicaria and P. arundinacea. The invasive had the highest stem stiffness. E. palustris was associated with the highest roughness value, closely followed by the invasive and C. vesicaria. Using modeling I found the presence of the invasive increased velocity compared to E. palustris and increased bed shear stress compared to C. vesicaria. Therefore, changes in species composition, such as a shift from either of the natives to the invasive, could affect channel morphology over time. By comparing the impact of this invasive to that of native grasses and sedges, this research provides insight into how further spread of the invasive may affect the Sprague River and other riparian ecotones. / 2015-10-03

Abstract Healthy subjects show wide interindividual variation in their heart rate behavior, but the factors affecting heart rate dynamics are not well known. This research was undertaken to evaluate heart rate variability (HRV) and baroreflex sensitivity (BRS) in a large random sample of subjects without evidence of heart disease, and to estimate the relation of heart rate behavior to age, sex and cardiovascular risk factors. Short-term HRV was analyzed from 15-minute periods of standardized recording in supine and upright positions using time and frequency domain measures, and BRS was calculated using the Valsalva maneuver in an original randomly selected population of 600 hypertensive and 600 control middle-aged subjects. In addition, HRV was analyzed from the same segments using new measures based on fractals and complexity (chaos theory) of R - R interval dynamics in the same random population, and from 24-hour period in 114 healthy subjects aged from 1 to 82 years. Large interindividual variation was observed in the measures of HRV and BRS in middle-aged subjects; coefficient of variation (CV) of the standard deviation of R - R intervals (SDNN) 39% (54 ± 21 ms) and CV of BRS 49% (9.9 ± 4.9 ms/mmHg). In healthy middle-aged men, SDNN was weakly related to age (r = -0.19, p &lt; 0.01), HDL cholesterol (0.19, p &lt; 0.01), serum insulin (-0.23, p &lt; 0.001) and triglyceride (-0.25, p &lt; 0.001) levels. In women, SDNN was only related to insulin levels (r = -0.23, p &lt; 0.001). BRS was related to systolic blood pressure (r = -0.31 and -0.30, in men and women respectively, p &lt; 0.001 for both) and blood glucose (r = -0.25, p &lt; 0.01) and serum insulin levels (r = -0.34, p &lt; 0.001) in women. Lesser intersubject variation was observed in the non-linear measures of HRV; CV 14% of short-term scaling exponent (a1), a measure of fractal-like correlation properties of HRV, (1.21 ± 0.17) and CV 12% of approximate entropy, a measure of complexity, (1.13 ± 0.14). Neither a1 or ApEn was related to any risk factors. Women had lower overall short-term HRV (p &lt; 0.01) and BRS (p &lt; 0.001), but a higher spectral high-frequency component of HRV, higher ApEn and lower a1 (p &lt; 0.001 for all) compared to men. The impairment in overall HRV was confined to the hypertensive subjects with metabolic features of the insulin resistance syndrome (IRS, n = 69), but the BRS and spectral high-frequency component were also impaired in hypertensive subjects without IRS compared to normotensive subjects. The 24-hour cardiac interbeat interval dynamics changed markedly from childhood to old age. Children showed similar complexity and fractal correlation properties of R - R intervals as young adults. Healthy aging resulted in R - R interval dynamics with higher regularity and predictability and altered fractal scaling. The traditional measures of HRV and BRS are weakly related to many cardiovascular risk factors in subjects without heart disease, but the interindividual variation of HRV and BRS is only partly explained by these factors, suggesting a genetic background of the intersubject variation in cardiovascular autonomic regulation. The new dynamical measures of HRV show less interindividual variation than the conventional measures of HRV in healthy subjects and are not related to cardiovascular risk variables, suggesting that these dynamical measures quantify the "intrinsic" capacity of a healthy cardiovascular control system without the significant influence of life-style, metabolic or demographic variables. However, there are sex and age-related differences also in the fractal and complexity measures of heart rate behavior.

In the next century, the world’s ecosystems are going to change dramatically. Within the Mississippi Delta, shrinking swamps, degraded wetlands, and invasive species of current day southern Louisiana will only continue to evolve. Plant distribution and range, weather patterns and storm frequencies, and uncontrollable growth of weeds are expected to have a huge impact on our environment. Weeds, any non-planned plant, are expected to grow more fiercely with rising levels of pollution, a warmer climate, and higher CO2 levels. Some consider weeds as being at the heart of environmental ruination; they must must be eradicated and they must be destroyed. Arguably, human impact plays a more significant role concerning the integrity of the environment. These are constructed and now changing ideas surrounding nature. In many cases, weeds and invasive species are detrimental. But these plants are also perfectly acclimated to their surroundings, offering the opportunities of phytoremediation, erosion control, storm water control, and even habitat creation with no use of resources and at no monetary cost. The Louisiana landscape has been irrevocably changed through geographical and climatic processes as well as human intervention. Its permanent transformation is expected with not only its shifting ecology but rising sea levels, erosion, and saltwater intrusion. Complete submersion is imminent in the next few centuries. Like the act of keeping New Orleans dry, there is tension between releasing human control over larger environmental systems and saving what we know and understand. Rather than working against nature, an architecture of awareness and acknowledgement of present circumstances and an anxious future can be established. This thesis seeks to investigate the evolving landscape of the future Louisiana coast through the design of a mutually beneficial system that is conscious of both the destruction and benefits of invasive plants. How can the existing and expected landscape occupants be productive and useful? How can the elements that make southern Louisiana so special be adapted for our changing ecologies? And what is the role of architecture in an evolving landscape on the brink of collapse? This thesis hopes to illuminate the ways in which something (sometimes seemingly) destructive can be positive, productive, and conscious. Considering shifting ecologies, how can architecture merge with the new landscapes and adapt to our present preservation needs now and environmental concerns in the future? / 0 / SPK / specialcollections@tulane.edu