In the summer of 1932, an investigation of some biological, physical, and chemical conditions at the Bear River Migratory Waterfowl Refuge, Utah, was begun at the Utah State Agricultural College to determine some of the factors governing the biological productivity of brackish-water marshes. Unfortunately, lack of funds made it impossible to continue work beyond the first season.

The breeding biology of western grebe was studied at Bear River Migratory Bird Refuge, Utah in 1973 and 1974. More than 300 nests were located and data gathered on nesting habitat and success. Western grebe at Bear River selected nest sites for nearness to open water of approximately 30 em in depth. At least one young was hatching in 21 percent of the nests. Avian predation and abandonment of nests following drops in water levels caused the greatest loss of nests. Chlorinated hydrocarbons monitored in western grebes showed DDE, DDD, PCB, 1260, and PCB 1254 levels in 24 breast muscle samples (wet weight) to average 12. 8, 0. 8, 3. 8, and 3. 5 ppm respectively. Contaminant concentration was found to be correlated to the condition of the bird as determined by visceral fat content. A significant (p<. 01) 2. 3 percent decline in western grebe eggshell thickness between preand post-DDT use periods was found. DDE was significantly (p<. 05) negatively correlated with eggshell thickness in western grebe. Contaminants were not linked to any reproductive failure in western grebe at Bear River MBR.

Several species of North American migratory songbirds reportedly experience seasonal diet shifts involving a shift from an insect diet during the breeding season to one incorporating fruits during migration and non-breeding periods but the extent to which dietary plasticity occurs in migratory songbirds is poorly quantified. Thus, I used stable carbon (ä13C) and nitrogen (ä15N) isotope analyses to evaluate the timing and extent of frugivory throughout the annual life cycle of 16 species of migratory songbirds, representing wide ranges in body size and reported diets. Birds were sampled during spring and fall migration at the Delta Marsh Bird Observatory in 2003. To investigate dietary patterns, I sampled multiple tissues (muscle, liver, whole blood, claws, bone collagen, feathers) as these represent different periods of diet integration due to varying elemental turnover rates.<p>Assuming that relatively low ä15N values represent a fruit diet and relatively high ä15N values represent an insect diet, I expected tissues representing fall migration (liver, blood, and muscle from fall-captured birds) and winter (greater coverts and claws from spring-captured birds) to have lower ä15N values than tissues representing spring migration (liver, blood, and muscle from spring-captured birds) and summer (tail feathers and claws from fall-captured birds) when fruits are presumed to be less common in songbird diets. Based on blood and claw ä15N values, there was no isotopic segregation of species I classified a priori as insectivores or omnivores. For most species, tissue ä15N values showed either no seasonal change or a shift opposite to my prediction (e.g., ä15N values higher in fall birds compared to spring birds). Boreal fruit ä15N values were lower than those for insects; however, ä15N values of agricultural fruits overlapped both boreal fruit and insect values suggesting that food web baselines did not conform to a simple (single) linear trophic-enrichment model. In Yellow-rumped Warblers (Dendroica coronata), within-tissue seasonal comparisons for liver, muscle and blood indicated a fruit diet during fall and winter and an insect diet during spring and summer; claws and feathers of birds captured in spring (representing winter diet) had unexpectedly high ä15N values. Diet-tissue isotopic discrimination factors associated with both a fruit diet and insect diet were taken from the literature and used to correct stable isotope values of tissues to putative diet because, currently, little is known about the nature of factors influencing discrimination factors to be used in simple linear dietary mixing models. There were differences in tissue ä13C and ä15N values depending on which discrimination factor was used. Based on mixing model results for tissue ä15N values, a higher proportion of insects vs. fruits was detected in the diet of Yellow-rumped Warblers for all tissues except muscle and claws. <p>My interpretations are contingent on the fact that the available natural history information, on which guild classifications were based, was correct and that elemental turnover rates and discrimination factors used were accurate. However, much uncertainty remains about the appropriate diet-tissue isotopic discrimination factors corresponding to fruit and insect diets. Due to extensive natural variability of stable nitrogen isotope values in food sources, possible anthropogenic influences and a lack of knowledge of the metabolic processes that can potentially affect stable isotope values, I caution against using stable isotope analysis alone to track frugivory in temperate North American migratory songbirds. Future research should focus on captive studies aimed at determining and validating discrimination factors of various tissues, particularly claws and feathers, for birds feeding on varying proportions of fruits and insects. Additionally, more information on the dietary habits of these migratory songbirds is needed, as previous estimates of insectivory and frugivory in songbirds may not be accurate.

Several species of North American migratory songbirds reportedly experience seasonal diet shifts involving a shift from an insect diet during the breeding season to one incorporating fruits during migration and non-breeding periods but the extent to which dietary plasticity occurs in migratory songbirds is poorly quantified. Thus, I used stable carbon (ä13C) and nitrogen (ä15N) isotope analyses to evaluate the timing and extent of frugivory throughout the annual life cycle of 16 species of migratory songbirds, representing wide ranges in body size and reported diets. Birds were sampled during spring and fall migration at the Delta Marsh Bird Observatory in 2003. To investigate dietary patterns, I sampled multiple tissues (muscle, liver, whole blood, claws, bone collagen, feathers) as these represent different periods of diet integration due to varying elemental turnover rates.<p>Assuming that relatively low ä15N values represent a fruit diet and relatively high ä15N values represent an insect diet, I expected tissues representing fall migration (liver, blood, and muscle from fall-captured birds) and winter (greater coverts and claws from spring-captured birds) to have lower ä15N values than tissues representing spring migration (liver, blood, and muscle from spring-captured birds) and summer (tail feathers and claws from fall-captured birds) when fruits are presumed to be less common in songbird diets. Based on blood and claw ä15N values, there was no isotopic segregation of species I classified a priori as insectivores or omnivores. For most species, tissue ä15N values showed either no seasonal change or a shift opposite to my prediction (e.g., ä15N values higher in fall birds compared to spring birds). Boreal fruit ä15N values were lower than those for insects; however, ä15N values of agricultural fruits overlapped both boreal fruit and insect values suggesting that food web baselines did not conform to a simple (single) linear trophic-enrichment model. In Yellow-rumped Warblers (Dendroica coronata), within-tissue seasonal comparisons for liver, muscle and blood indicated a fruit diet during fall and winter and an insect diet during spring and summer; claws and feathers of birds captured in spring (representing winter diet) had unexpectedly high ä15N values. Diet-tissue isotopic discrimination factors associated with both a fruit diet and insect diet were taken from the literature and used to correct stable isotope values of tissues to putative diet because, currently, little is known about the nature of factors influencing discrimination factors to be used in simple linear dietary mixing models. There were differences in tissue ä13C and ä15N values depending on which discrimination factor was used. Based on mixing model results for tissue ä15N values, a higher proportion of insects vs. fruits was detected in the diet of Yellow-rumped Warblers for all tissues except muscle and claws. <p>My interpretations are contingent on the fact that the available natural history information, on which guild classifications were based, was correct and that elemental turnover rates and discrimination factors used were accurate. However, much uncertainty remains about the appropriate diet-tissue isotopic discrimination factors corresponding to fruit and insect diets. Due to extensive natural variability of stable nitrogen isotope values in food sources, possible anthropogenic influences and a lack of knowledge of the metabolic processes that can potentially affect stable isotope values, I caution against using stable isotope analysis alone to track frugivory in temperate North American migratory songbirds. Future research should focus on captive studies aimed at determining and validating discrimination factors of various tissues, particularly claws and feathers, for birds feeding on varying proportions of fruits and insects. Additionally, more information on the dietary habits of these migratory songbirds is needed, as previous estimates of insectivory and frugivory in songbirds may not be accurate.

Thesis (M. Sc.)--York University, 2001. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 106-118). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ66399.

abstract: The term "White flight" and its effects are well documented in large urban city centers. However, few studies consider the same effects on smaller American communities. This case study investigates Lexington, Nebraska, a rural community of approximately 10,000 citizens, that has experienced a population influx of minorities in the last 25 years. The population shift has increased the representation of Hispanic, Asian, and now Somali students in the Lexington Public School system, which, in turn, has been accompanied by a dramatic decrease in White, Anglo students. This study attempts to identify and describe the reasons for the exodus of White students from the public school setting. Possible reasons that might explain the decreases in White student enrollment may include overcrowding in schools, unsafe school environments, and/or less one-on-one attention with classroom teachers. / Dissertation/Thesis / Ed.D. Educational Leadership and Policy Studies 2011

En adoptant une approche qualitative et pluridisciplinaire, basée sur l’étude longitudinale des circulations de la population de Deir Mqaren - un village syrien situé entre Damas et la frontière libanaise - cette thèse interroge la dimension réticulaire des mobilités humaines. A travers les récits de vie des réfugiés de cette bourgade et l’analyse de leurs parcours migratoires vers la Jordanie et l’Allemagne, elle décrypte la mécanique des flux au départ de Syrie. Cette recherche invite ainsi le lecteur à déplacer son regard vers des réseaux de lieux et d’acteurs souvent considérés comme marginaux, mais formant pourtant l’ossature des routes de l’exil reliant la Syrie au reste du globe. En plaçant la focale sur les conditions du mouvement des individus, l’intention de cette étude est à la fois de mettre en exergue les imbrications entre les migrations économiques antérieures au conflit et la logique des mouvements actuels de réfugiés ; mais aussi de montrer de manière tangible l’évolution des mécanismes relationnels permettant aux exilés d’accéder à des ressources (informations, mobilité, logement, emploi) en dépit des contraintes structurelles auxquelles ils ne cessent d’être confrontés. Les représentations (carto)graphiques élaborées dans le cadre de cette thèse visent pour leur part à mieux rendre compte du caractère mobile, instable et particulièrement labile de ces dynamiques socio-spatiales. / In adopting a qualitative and multidisciplinary approach, based on the longitudinal study of the Deir Mqaren’s inhabitants’ circulations – a Syrian village located between Damascus and the Lebanese border – this thesis questions the “reticular” dimension of human mobility. Through refugees’ narratives and the analysis of their migration journeys to Jordan and Germany, its aims to understand the mechanics of refugee flows from Syria. Thus, this research invites the reader to move his focus towards networks of places and actors often considered as being marginal, despite the fact that they form the “backbone” of the roads of exile liking Syria to the rest of the world. By placing the focal point on individuals’ conditions of movement, the intention of this study is to both highlight the continuum existing between pre-conflict economic migration and the logic of the current refugee movements; and show in a tangible way the evolution of the relational mechanisms allowing exiles to access resources (such as information, mobility, housing, employment) despite the structural constraints they are constantly facing on their way towards safe destinations. The graphic representations developed in the framework of this thesis aim to better reflect the mobile, unstable and particularly labile nature of these socio-spatial dynamics.

abstract: Avian influenzas are zoonoses, or pathogens borne by wildlife and livestock that can also infect people. In recent decades, and especially since the emergence of highly pathogenic avian influenza (HPAI) H5N1 in 1996, these diseases have become a significant threat to animal and public health across the world. HPAI H5N1 has caused severe damage to poultry populations, killing, or prompting the culling of, millions of birds in Asia, Africa, and Europe. It has also infected hundreds of people, with a mortality rate of approximately 50%. This dissertation focuses on the ecological and socioeconomic drivers of avian influenza risk, particularly in China, the most populous country to be infected. Among the most significant ecological risk factors are landscapes that serve as “mixing zones” for wild waterfowl and poultry, such as rice paddy, and nearby lakes and wetlands that are important breeding and wintering habitats for wild birds. Poultry outbreaks often involve cross infections between wild and domesticated birds. At the international level, trade in live poultry can spread the disease, especially if the imports are from countries not party to trade agreements with well-developed biosecurity standards. However, these risks can be mitigated in a number of ways. Protected habitats, such as Ramsar wetlands, can segregate wild bird and poultry populations, thereby lowering the chance of interspecies transmission. The industrialization of poultry production, while not without ethical and public health problems, can also be risk-reducing by causing wild-domestic segregation and allowing for the more efficient application of surveillance, vaccination, and other biosecurity measures. Disease surveillance is effective at preventing the spread of avian influenza, including across international borders. Economic modernization in general, as reflected in rising per-capita GDP, appears to mitigate avian influenza risks at both the national and sub-national levels. Poultry vaccination has been effective in many cases, but is an incomplete solution because of the practical difficulties of sustained and widespread implementation. The other popular approach to avian influenza control is culling, which can be highly expensive and raise ethical concerns about large-scale animal slaughter. Therefore, it is more economically efficient, and may even be more ethical, to target the socio-ecological drivers of avian influenza risks, including by implementing the policies discussed here. / Dissertation/Thesis / Doctoral Dissertation Biology 2018

Submitted by Valquíria Barbieri (kikibarbi@hotmail.com) on 2018-04-10T19:32:13Z No. of bitstreams: 1 DISS_2014_Gabriela Maria Maimone de Figueiredo.pdf: 941864 bytes, checksum: 484a34af643f773276e576c7baaae016 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-04-26T17:22:46Z (GMT) No. of bitstreams: 1 DISS_2014_Gabriela Maria Maimone de Figueiredo.pdf: 941864 bytes, checksum: 484a34af643f773276e576c7baaae016 (MD5) / Made available in DSpace on 2018-04-26T17:22:46Z (GMT). No. of bitstreams: 1 DISS_2014_Gabriela Maria Maimone de Figueiredo.pdf: 941864 bytes, checksum: 484a34af643f773276e576c7baaae016 (MD5) Previous issue date: 2014-03-17 / CNPq / Este estudo teve como objetivo avaliar a distribuição espacial e temporal das assembleias do ictioplâncton do rio Cuiabá e áreas adjacentes, no período de novembro de 2007 a fevereiro de 2008, bem como estudar as relações de densidades dos ovos e larvas com os fatores locais físicos (temperatura, velocidade da água) químicos (fosfato, nitrogênio total, nitrogênio amoniacal), como indicadores da produtividade no ambiente, fatores bióticos (densidades de fitoplâncton e zooplâncton) e com os fatores regionais (nível do rio e pluviosidade), formando condições e locais favoráveis para seu desenvolvimento e sobrevivência nos estágios iniciais de vida dos peixes. As coletas do ictioplâncton foram realizadas em 14 pontos ao longo do rio e áreas adjacentes, com arrastos sub-superficiais de 20 e 40 cm de profundidade, com rede tipo cilindro-cônica de malha 300 μm. Concomitantemente, foram coletadas amostras de fitoplâncton e zooplâncton, bem como realizadas as medidas das variáveis locais e regionais. Após as coletas as amostras foram triadas e identificadas ao menor nível taxonômico possível. Para avaliar as diferenças nas densidades de ovos e larvas nos locais e nos meses de estudo, foi utilizado o teste de ANOVA por medidas repetidas. Foi utilizada uma correlação de Spearman para a análise das densidades de ovos e larvas com as variáveis regionais e com as variáveis locais. Para avaliar as densidades das larvas com as densidades do fitoplâncton e do zooplâncton também foi utilizada a correlação de Spearman, porém, este teste foi feito com as larvas que foram identificadas em nível de gênero e espécie, e posteriormente, com cada espécie de larva de peixe migrador. Para analisar a composição das estruturas das assembleias de larvas através das densidades nos locais foi utilizado o teste de Mantel parcial, entre as distâncias de similaridades, distâncias ambientais e geográficas. Para avaliar a diferença temporal entre os grupos de Characiformes e Siluriformes foi feito o teste de ANOVA por medidas repetidas. Foi realizada uma ordenação direta das densidades das larvas dos migradores nos pontos amostrais. Os resultados espaciais com as densidades de ovos (F1;10= 0,572; p=0,467), e larvas (F1;10= 3,494 ; p=0,091) não foram significativos. Os resultados temporais com as densidades de ovos (F3;30= 0,533; p=0,663) não foram significativos, já para as larvas (F3;30= 4,539; p=0,009) foram significativos, com picos de densidades em novembro e janeiro. Houve correlação significativa entre as densidades das larvas com o nitrogênio total (r=-0,127; p=0,025) e a temperatura da água (r=0,292; p=0,035). O teste de Mantel parcial mostrou que a variação ambiental não foi fator determinante na distribuição da composição taxonômica dos grupos ao longo do rio (r=-0,214; p=0,966) e que as assembleias de larvas apresentam significativa dependência geográfica (r=0,459; p=0,001), quanto mais próximos os pontos geograficamente, mais similares foram as composições taxonômicas. Os resultados taxonômicos mostraram diferença temporal significativa (F3;48= 3,994; p=0,012) entre os grupos dos Siluriformes e Characiformes. / The aim of this study is to assess the spatial and temporal distribution of Ichthyoplankton assemblies of the Cuiabá River and adjacent areas, from November 2007 to February 2008. We also studied the relationships of egg and larvae density with local physical factors (temperature, water velocity) chemical (phosphate, total nitrogen, ammoniac nitrogen) as indicators of productivity in the environment, abiotic factors (densities of phytoplankton and zooplankton), and with regional factors (the river level and rainfall), as they form favorable conditions and locations for their development and survival in the earlier stages of fish life. Ichthyoplankton samples were conducted in 14 points along the river, with subsurface water of 20 and 40 cm deep, with cylinder-type nets of 300 μm. Concomitantly, were collected samples of phytoplankton and zooplankton, and measured the local and regional variables. After the data collecting, the samples were sorted out and identified to the lowest taxonomic level possible. To evaluate differences in densities of eggs and larvae in the localities and in the months of study, ANOVA for repeated measurements was applied. Spearman correlation was used for the analysis of densities of eggs and larvae with regional and local variables. To evaluate larval densities with densities of phytoplankton and zooplankton we also used the Spearman correlation, however, this test was done with larvae that were identified at the level of genus and species, and later, with each species of migrating fish larvae. To analyze the composition of the structure of assemblies of larvae through the densities at the localities, we applied the partial Mantel test, between the distances of similarities, environmental and geographic distances. To evaluate the temporal difference between the groups of Characiformes and Siluriformes, we applied an ANOVA for repeated measurements. A direct ordering of the migratory larvae densities in sampling points was done. The spatial results with egg densities (F1;10= 0,572; p=0,467), and larvae (F1;10= 3,494 ; p=0,091) were not significant. Temporal results with egg densities (F3;30= 0,533; p=0,663) were not significant, however for the larvae (F3;30= 4,539; p=0,009) the results were significant with peaks in November and January. There was a significant correlation between larval densities and total nitrogen (r=-0,127; p=0,025) and the water temperature (r=0,292; p=0,035). The partial Mantel test has shown that the environmental variation was not a determining factor in the distribution of the taxonomic composition of groups along the basin (r=-0,214; p=0,966). The larvae assemblies show significant geographic dependence (r=0,459; p=0,001), the closer the dots geographically, the more similar were the taxonomic compositions. Taxonomic results show significant temporal difference (F3;48= 3,994; p=0,012) between groups of Siluriformes and Characiformes.

Eurasian Reed Warbler (Acrocephalus scirpaceus) is a long-distance migrant wintering in sub-Saharan Africa and breeding in reedbeds of the Western Palaearctic. European populations migrate in two main directions (SW and SE). Though there is little morphological variation across the breeding range, Asian populations are traditionally separated from the nominate subspecies as the subspecies fuscus. My aim was to explore genetic differentiation among Eurasian Reed Warbler populations in respect to the factors which may have influenced the genetic diversity and divergence of the populations, such as a migratory divide, high migratory connectivity or isolation by distance. I used samples of 495 individuals from 36 populations across the breeding range using microsatellites. Pairwaise fixation indexes FST showed significant differences among populations from the Iberian peninsula, Finland and the Middle East and the rest of populations. Exact tests of differentiation did not confirm non-random distribution between pairs of populations. Overall FST was statistical significant but very small (FST = 0,018). Analysis of molecular variance (AMOVA) revealed that 98% of variation was ascribable to variability of allele frequencies within populations. On the other hand, differences between populations contributed to overall variation with only 2%. Isolation by distance showed only weak relationship between geographical and genetic distances. Main analysis using Bayesian clustering approach implemented in software Structure 2.2. detected no genetic structure of population. Sampled Eurasian Reed Warbler populations seem to form one genetic population. Relatively low genetic diversification indicates large dispersal potential of the studied Reed Warbler populations, when gene flow successfully counters differentiation of population irrespective of large breeding area and high migrate connectivity between breeding and wintering area.