The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on November 19, 2009). Thesis advisor: Dr. John R. Jones. Includes bibliographical references.

I evaluated the potential for interspecific competition for forage between elk (Cervus elaphus) and bison (Bison bison) in the 265.5-ha Elk & Bison Prairie enclosure at Land Between The Lakes National Recreation Area in western Kentucky. I studied diet composition of elk and bison based on microhistological analysis of fecal samples collected monthly for 36 months from September 1996 through August 1999. Elk diet was more variable than that of bison, but no significant seasonal differences in diet composition were found for either species throughout the study. As expected, elk and bison differed significantly in their feeding habits. As seen in studies of wild sympatric populations, bison consumed more graminoids, less browse and fewer forbs than did elk, regardless of season. Dietary overlap varied considerably, but with little apparent seasonal pattern. Overlap did not consistently increase during winter, when quantity and quality of available forage might be reduced. Competition between elk and bison for available forage may have been alleviated by supplemental feeding and the ability of elk to adapt to alternative forages.

I evaluated diet and food selection of 5 species of spring-migrating female waterfowl including 3 dabbling ducks (Blue-winged teal, Anas discors, Mallard, Anas platyrhynchos, Gadwall, Anas strepera) and 2 diving ducks (Lesser Scaup, Aythya affinis, and Ring-necked duck, Aythya collaris). Diet was evaluated with regards to the proportion of invertebrates and seeds consumed, and compared to forage availability data collected in habitats available to them at 6 study locations throughout the Upper Mississippi River and Great Lakes Region. I found latitude (i.e., stage of migration), longitude, food availability, and date all influenced the diet of spring migrating waterfowl, with some factors having a stronger influence than others. I observed differing diet trends with regard to foraging guild (e.g., dabbling and diving ducks), as each foraging guild was represented by 1 species that was heavily dependant on invertebrates (dabbling duck - Blue-winged teal; diving duck - Lesser scaup) and 1 species that was heavily dependant on seeds (dabbling duck - Mallard; diving duck - Ring-necked duck). The proportion of invertebrate foods in the diet increased throughout spring for all species of waterfowl, suggesting the importance of invertebrate food sources during spring staging. Data from this study provides valuable information to habitat managers and conservationists wishing to improve spring habitat conditions for migrating waterfowl, which likely influences waterfowl productivity.

Durante décadas, a visão prevalente em ecologia de microrganismos era de que os fatores ambientais locais seriam os únicos agentes estruturantes das comunidades e dos padrões de coexistência das espécies. Entretando, estudos recentes têm fornecido evidência de que processos ligados a dispersão possam ser tão importantes quanto o ambiente local na estruturação das comunidades, reacendendo o debate em torno da hipótese clássica sobre a ubiquidade dos microrganismos. Neste estudo, nós examinamos os padrões de coexistência do fitoplâncton e os possíveis determinantes da variação espacial na composição das comunidades em 9 lagoas do sul do Brasil. Nós testamos se as espécies fitoplanctônicas apresentam um padrão não aleatório de coexistência através de um modelo nulo e se distância espacial ou a distância ambiental possuem relação com a similaridade na composição das comunidades. Nós também investigamos se as variáveis ambientais locais são bons preditores da abundância das espécies. Na análise de coexistência, nós não observamos um padrão significativo de estruturação dentro das lagoas, mas encontramos um padrão não-aleatório e segregado das espécies ao longo das lagoas, indicando que as espécies coexistem menos do que o esperado ao acaso nesta escala. A similaridade na composição das comunidades mostrou correlação significativa com a distância ambiental, mas não foi correlacionada com a distância geográfica entre os sítios. Além disso, a variação na abundância das espécies apresentou correlação significativa com as variáveis ambientais locais (transparência da água, condutividade, nitrato e ortofosfato). Em conclusão, nossos resultados apoiam a visão de que a variação espacial do fitoplâncton é melhor explicada pelo ambiente local. Nós não testamos a influência de variáveis históricas e filogenéticas sobre esses padrões, que podem ser temas de estudos futuros, a fim de elucidar ainda mais essas questões. / For decades, the main hypothesis in microbial ecology was that local environment would be the only mechanism structuring communities and patterns of species coexistence. However, recent studies have provided evidence that processes related to dispersion can be as important as the local environment for shaping biological communities, stimulating new debates on the classical hypothesis about the ubiquity of microorganisms. In this study, we examined the phytoplankton coexistence patterns and possible determinants of spatial variation in community composition in 9 lakes of southern Brazil. First, we use a null model analysis for tested whether the phytoplankton species show a nonrandom pattern of coexistence. We also tested whether spatial distance or environmental distance act as potential factors controlling community composition. Finally, we investigated whether local environmental variables are good predictors of species abundance. We did not observe a significant pattern of coexistence species in the within-lakes analysis, but we found a nonrandom pattern of coexistence and segregation of species across-lakes analysis, indicating that the species coexist less than expected by chance on this scale. Phytoplankton community composition showed a strong positive correlation with the environmental distance but was not correlated with the geographical distance between sites. Moreover, the variation in the abundance of species showed significant correlation with local environmental variables (water transparency, conductivity, nitrate and orthophosphate). In conclusion, our results support the view that the spatial variation of phytoplankton is best explained by the local environmental conditions. We suggest that the influences of historical and phylogenetic variables on these patterns, here not measured, be analyzed in future studies, to further elucidate these questions.

Durante décadas, a visão prevalente em ecologia de microrganismos era de que os fatores ambientais locais seriam os únicos agentes estruturantes das comunidades e dos padrões de coexistência das espécies. Entretando, estudos recentes têm fornecido evidência de que processos ligados a dispersão possam ser tão importantes quanto o ambiente local na estruturação das comunidades, reacendendo o debate em torno da hipótese clássica sobre a ubiquidade dos microrganismos. Neste estudo, nós examinamos os padrões de coexistência do fitoplâncton e os possíveis determinantes da variação espacial na composição das comunidades em 9 lagoas do sul do Brasil. Nós testamos se as espécies fitoplanctônicas apresentam um padrão não aleatório de coexistência através de um modelo nulo e se distância espacial ou a distância ambiental possuem relação com a similaridade na composição das comunidades. Nós também investigamos se as variáveis ambientais locais são bons preditores da abundância das espécies. Na análise de coexistência, nós não observamos um padrão significativo de estruturação dentro das lagoas, mas encontramos um padrão não-aleatório e segregado das espécies ao longo das lagoas, indicando que as espécies coexistem menos do que o esperado ao acaso nesta escala. A similaridade na composição das comunidades mostrou correlação significativa com a distância ambiental, mas não foi correlacionada com a distância geográfica entre os sítios. Além disso, a variação na abundância das espécies apresentou correlação significativa com as variáveis ambientais locais (transparência da água, condutividade, nitrato e ortofosfato). Em conclusão, nossos resultados apoiam a visão de que a variação espacial do fitoplâncton é melhor explicada pelo ambiente local. Nós não testamos a influência de variáveis históricas e filogenéticas sobre esses padrões, que podem ser temas de estudos futuros, a fim de elucidar ainda mais essas questões. / For decades, the main hypothesis in microbial ecology was that local environment would be the only mechanism structuring communities and patterns of species coexistence. However, recent studies have provided evidence that processes related to dispersion can be as important as the local environment for shaping biological communities, stimulating new debates on the classical hypothesis about the ubiquity of microorganisms. In this study, we examined the phytoplankton coexistence patterns and possible determinants of spatial variation in community composition in 9 lakes of southern Brazil. First, we use a null model analysis for tested whether the phytoplankton species show a nonrandom pattern of coexistence. We also tested whether spatial distance or environmental distance act as potential factors controlling community composition. Finally, we investigated whether local environmental variables are good predictors of species abundance. We did not observe a significant pattern of coexistence species in the within-lakes analysis, but we found a nonrandom pattern of coexistence and segregation of species across-lakes analysis, indicating that the species coexist less than expected by chance on this scale. Phytoplankton community composition showed a strong positive correlation with the environmental distance but was not correlated with the geographical distance between sites. Moreover, the variation in the abundance of species showed significant correlation with local environmental variables (water transparency, conductivity, nitrate and orthophosphate). In conclusion, our results support the view that the spatial variation of phytoplankton is best explained by the local environmental conditions. We suggest that the influences of historical and phylogenetic variables on these patterns, here not measured, be analyzed in future studies, to further elucidate these questions.

The Great Lakes region covers central, eastern and some parts of southern Africa. It is situated strategically in the middle of the African continent and its stability, peace and development is imperative for the African continent. Inter and Intra-state conflicts have gone on in the region for the past couple of decades. These conflicts, which threatened to become a regional war, seem to have come to an end, but have left terrible reminders including the presence of masses of internally displaced persons. Various attempts have been made within the Great Lakes at state and regional level to address the issue of internal displacement. This study has highlighted these attempts while outlining the major setbacks and the gaps manifesting in existing institutional and legal framework. The study further has proposed the need for a comprehensive legal framework which should among other things codify the standards of protection; provide for the means and institutions of coordinating protection and assistance in all phases of displacement; serve as a legal basis for coordinating various regional and international actors and agencies involved in providing protection and assistance for internally displaced persons in Africa; highlight the measure or level of political will to achieve this; and finally provide means of monitoring such protection and assistance and ensure compliance by states. The study has also highlighted that existing frameworks, legal and institutional within the Great Lakes region and through additional aid from international mechanisms and actors are not adequate to resolve the issue of internal displacement within the region permanently and find durable solutions to millions of people laboring from protracted displacement. The study suggests alternative reliance on African systems and their conceptual contribution to the resolution of conflict and displacement in Africa and the Great Lakes in particular. The Final part of the study looks at national attempts to address the problem of internal displacement. Kenya and Uganda are discussed and contrasted in depth whilst highlighting their similarities and differences in addressing internal displacement. Both countries have at one point or the other experienced internal displacement, although not necessarily on the same scale, dynamics, time frame or even severity. They both seem to have taken incredible steps to address the issue of internal displacement including drafting policies, laws as well as assigning responsibilities for the displaced to specific ministries of government. Internally displaced persons in both countries seem to be in the process of returning home, even though at very different scales, and not always necessarily as a durable solution. These two countries have been used as case studies for identifying the domestic process of addressing internal displacement as well as determining the degree of comprehensiveness of the frameworks set up to address internal displacement. / Thesis (LLD)--University of Pretoria, 2012. / Jurisprudence / unrestricted

Philosophiae Doctor - PhD / This dissertation is an exploration of everyday social interactions among and between migrants from the Great Lakes Region and South Africans, who live together as neighbours in a post-apartheid South African community. It focuses on the ways through which migrants who are diverse among themselves forge social relations with one another and with the South Africans in an urban township of lower middle class setting. It is an ethnography that interrogates the understandings of belonging and difference in concrete arenas of interaction in these two groups, and how they both mediate their diversity encounters in everyday life.

Current dynamic of global climate change is the trigger of new natural processes such as glacial lake outburst floods. One example is lake Imja located in the hinterland of Mt. Everest. Outburst of lake Imja would have undoubtedly negative impact on financial and cultural climate of attached area. This diploma thesis is focusing on the various factors and its imapct on the stability of moraine. The main aim of this thesis is to evaluate possibility of impact of rockfall into the lake, to monitor the development of its expansion in comparison with growing temperatures in last 60 years and also to assess the development of morphology of moraine containing dead ice. The results of the thesis indicate accelerating expansion of the lake at the expense of the Imja and Lhotse Shar glaciers, for which the rising means of temperatures of the months in the warm half of the year are particularly important. The results also show that there is no risk of producing wave after impact of rockfall into the lake, as the lateral moraines are sufficiently high to protect the lake. The crucial factor for the stability of the moraine dam is the melting of dead ice in its core, where new and new thermokarst lakes are forming on the surface of the moraine and a seepage through the moraine in its southwestern part has also...

Endemic species flocks inhabiting ancient lakes, oceanic islands and other long-lived isolated habitats are often interpreted as adaptive radiations. Yet molecular evidence for directional selection during species flocks radiation is scarce. Using partial transcriptomes of 64 species of Lake Baikal (Siberia, Russia) endemic amphipods and two nonendemic outgroups, we report a revised phylogeny of this species flock and analyse evidence for positive selection within the endemic lineages. We confirm two independent invasions of amphipods into Baikal and demonstrate that several morphological features of Baikal amphipods, such as body armour and reduction in appendages and sensory organs, evolved in several lineages in parallel. Radiation of Baikal amphipods has been characterized by short phylogenetic branches and frequent episodes of positive selection which tended to be more frequent in the early phase of the second invasion of amphipods into Baikal when the most intensive diversification occurred. Notably, signatures of positive selection are frequent in genes encoding mitochondrial membrane proteins with electron transfer chain and ATP synthesis functionality. In particular, subunits of both the membrane and substrate-level ATP synthases show evidence of positive selection in the plankton species Macrohectopus branickii, possibly indicating adaptation to active plankton lifestyle and to survival under conditions of low temperature and high hydrostatic pressures known to affect membranes functioning. Other functional categories represented among genes likely to be under positive selection include Ca-binding muscle-related proteins, possibly indicating adaptation to Ca-deficient low mineralization Baikal waters.

The Quaternary geologic history of Lake Thatcher, southeastern Idaho, is pivotal in determining when the Bear River carved its through-flowing channel into the Bonneville Basin. Bright's reconstruction of the history of Lake Thatcher was based on 14C dates that are now known to be inaccurate. Lava Creek B ash found interbedded with lacustrine sediment suggests that Thatcher Basin contained a lake well before Bright's original estimate of 34 ka. D/L ratios, which measure the extent of racemization in fossil gastropods, in conjunction with paleosols and tephra, were used to correlate between four localities across Thatcher Basin to reassess lake-level chronology. Lab-heating experiments were performed on four genera of molluscs to obtain integeneric conversions of D/L, which aided in chronostratigraphic correlation between beds that contained different genera. An age calibration curve for Lymnaea was developed using D/L ratios associated with the proto Mount St. Helens tephra (90±30 ka; D/L=0.21 [Valvata]) and Lake Bonneville sediment (20±5 ka; D/L=0.09 [lymnaea]). D/L ratios from non-dated lake deposits were assigned ages using this calibration curve, providing the basis for the late-Pleistocene Lake Thatcher chronology. Based on high D/L ratios in Valvata (~0.7) contained in the lower Thatcher sediment, lake level through early-middle Pleistocene was shallow, evidenced by numerous paleosols and organic-rich beds. A gap in the Lake Thatcher stratigraphic record exists for much of the middle Pleistocene. Lake Thatcher existed at its highest elevation from ~110 until ~80 ka, separated from the final Lake Thatcher high-water episode at ~40 ka by a middle-Wisconsin soil. This provides a maximum age on the breaching of the divide at Oneida Narrows and unimpeded flow of the Bear River into Bonneville Basin. By ~17 ka, Lake Bonneville backed up into Thatcher Basin, during its all-time highstand, which Bright believed was owned in part to the added inflow of the Bear River. However, evidence from this study suggests that the Bear River may have been spilling over the divide at Oneida Narrows into Bonneville Basin at ~110 ka.