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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Conservação de mamíferos de médio-grande porte em paisagem agrícola: estrutura de assembleias, ecologia trófica e diversidade funcional / Conservation of medium and large-sized mammals in agricultural landscapes: assemblages structure, trophic ecology and functional diversity

Marcelo Magioli 04 December 2013 (has links)
A escassez de trabalhos acerca dos impactos causados por mosaicos agrícolas sobre a biodiversidade dificulta a criação de estratégias de conservação, havendo necessidade de informações acerca da ecologia e comportamento de espécies da fauna. Nesse contexto o presente estudo objetivou: 1) determinar a composição e estrutura de assembleias de mamíferos de médio e grande em uma paisagem agrícola de Mata Atlântica; 2) avaliar o padrão de alimentação da onça-parda (Puma concolor) por meio da análise de isótopos estáveis (SIA) em dois mosaicos agrícolas; 3) analisar por meio da diversidade funcional (FD) assembleias de mamíferos em remanescentes florestais distribuídos nas principais regiões biogeográficas da Mata Atlântica, e identificar limiares ecológicos para a conservação. Para o inventário, foram selecionados oito remanescentes florestais na Região Metropolitana de Campinas (RMC), São Paulo. Os dados foram coletados por busca ativa (visualizações e vestígios), resultando no registro de 34 espécies de mamíferos, sendo 27 de médio e grande porte, quatro de pequeno porte, e três exóticas. Sete espécies se encontram ameaçadas de extinção, com registros inéditos de Myrmecophaga tridactyla e Lycalopex gymnocercus. A riqueza e a composição de espécies registradas apontaram a RMC como importante para a conservação da mastofauna. Foram analisados isotopicamente (carbono e nitrogênio) pelos de onças-pardas, obtidos a partir de amostras fecais coletadas por busca ativa em remanescentes florestais inseridos em paisagens agrícolas no interior do estado de São Paulo. Houve maior consumo de presas C3 (~47% dos indivíduos) na área com maior proporção de vegetação nativa, e maior consumo de presas C4 (~40% dos indivíduos) para a área onde é predominante a matriz agrícola. Foi constatado o consumo de presas com dieta baseada em itens alimentares dos remanescentes e da matriz agrícola, sugerindo alta plasticidade comportamental das onças-pardas e de suas presas ocupando áreas fortemente impactadas pelo homem. A ferramenta isotópica apresentou informações pioneiras sobre ecologia trófica, podendo contribuir na elaboração estratégias de conservação em áreas antropizadas. Para a análise da FD e identificação dos limiares foi utilizado um banco de dados composto por 49 assembleias de mamíferos, criado a partir de dados primários e secundários de inventários, sendo selecionadas 38 características das espécies para o cálculo. A existência de limiares foi verificada utilizando a função \"segmented\", disponível no programa R. A FD apresentou-se diferente para assembleias com o mesma riqueza de espécies, indicando que filtros ambientais podem influenciar nos valores. O incremento gradual na FD devido ao aumento da área dos remanescentes mostrou uma relação positiva, possivelmente ligada a maior complexidade e heterogeneidade de áreas maiores. Foram identificados dois limiares (52 e 1244 ha), criando três situações funcionalmente distintas, tanto críticas quanto mais estáveis, permitindo definir e propor formas de ação específicas. Assembleias presentes entre os limiares apresentaram incremento funcional significativo entre FD e o aumento da área dos remanescentes, e ações visando à restauração e melhorias na configuração da paisagem devem ser incentivadas. Conclui-se, portanto, que tanto a SIA quanto a FD, podem ser consideradas importantes ferramentas para delinear estratégias e ações em prol da conservação da mastofauna. / The scarcity of studies regarding the impacts of agricultural mosaics on biodiversity hinders the creation of conservation strategies and a need for information concerning the ecology and behavior of wildlife species. In this context, the present study aimed to: 1) determine the composition and structure of mammal assemblages of medium and large sized in an agricultural landscape at Atlantic Forest; 2) evaluate the puma (Puma concolor) feeding pattern through analysis of stable isotopes (SIA) in two agricultural mosaics; 3) analyze mammal assemblages by functional diversity (FD) in forest remnants distributed in major biogeographic regions of the Atlantic Forest, and identify ecological thresholds for conservation. For mammal\'s inventory, eight forest remnants were selected in Campinas Metropolitan Region (RMC), São Paulo state. Data were collected through active search (visualizations and tracks), resulting in the record of 34 mammal species, 27 medium and large size, four of small size, and three exotic. Seven species are threatened with extinction, with novel records of Myrmecophaga tridactyla and Lycalopex gymnocercus for this region. The species richness and composition pointed RMC as an important area for mammal\'s conservation. Carbon and nitrogen stable isotopes were analyzed in pumas hair, obtained from fecal samples collected by active search in forest remnants embedded in agricultural landscapes in São Paulo state. There was a higher consumption of C3 prey (~ 47% of individuals) in the area with the highest proportion of forest coverage, and greater consumption of C4 prey (~ 40% of individuals) where the agricultural matrix was predominant. Was observed the consumption of prey with diet based on food items from both forest remnants and agricultural matrix, suggesting high behavioral plasticity of puma\'s and their prey\'s occupying areas heavily impacted by man. Stable isotopes contributed with pioneer information on trophic ecology, aiming the development of new conservation strategies in anthropogenic areas. A database consisting of 49 mammal\'s assemblages, created from primary and secondary data of inventories, was used for FD analysis and threshold\'s identification. 38 specie\'s traits were selected for FD calculation. The thresholds existence was verified using the \"segmented\" function, available on R program. FD was different between mammal assemblages with the same species richness, indicating that environmental filters may affect its values. The gradual increment in FD, due to the increase in forest remnants area, presented a positive relationship, possibly linked to the increased complexity and heterogeneity of large areas. Two thresholds (52 and 1244 ha) were identified, creating three functionally distinct situations, both critical as more stable, allowing to define and propose for each one specific ways of action. Mammal\'s assemblages found between the thresholds showed significant functional increment considering the relationship between FD and forest remnants area, and actions aiming biological restoration and improvements in the landscape configuration should be encouraged. It was concluded, therefore, that both SIA as the FD can be considered important tools to outline strategies and actions for mammal\'s conservation.
72

The Population Status and Diet of the North American River Otter in Ohio

Parise, Charles Thomas January 2021 (has links)
No description available.
73

Childhood diet and mobility at medieval (1240s AD) Solt-Tetelhegy, Hungary as reconstructed from stable carbon, nitrogen, and oxygen isotope analysis

Gugora, Ariana 01 January 2015 (has links)
Between 2005 and 2009, archaeologists excavated more than 100 skeletons from the medieval (1240s AD) Hungarian site of Solt-Tételhegy. Stable carbon and nitrogen isotope analyses were conducted on dental enamel and dentin from 24 individuals to examine their childhood diet. Although previous stable isotopic research has described the diet of medieval European peoples, this is the first such study on a medieval Hungarian population. The enamel ?13C values range from -14.4‰ to -8.6‰, with a mean of -11.1‰, while the dentin ?13C values range from -19.4‰ to -14.9‰, with an average of -17.4‰. These data indicate that C3 plants were the main plant type consumed by the majority of this population, with the exception of a few individuals, who appear to have included C4 plants in their diet. These results are to be expected, given the dominance of C3 over C4 plants in medieval Central Europe. Thus, based on historical and isotopic evidence, the outliers may have spent their childhoods elsewhere and later migrated into the Solt-Tételhegy area. The ?15N values range from 9.5‰ to 11.6‰, with a mean of 10.6‰, indicating that animal protein was prevalent in the diets of the sample population. Despite clear signs of status differences indicated by burial location, stable nitrogen values also point to relatively egalitarian access to animal protein amongst the individuals. The enamel ?18Op values range from 23.6‰ to 27.2‰, with an average of 25.1‰, suggesting that multiple migrations occurred into the study site. The results of this study show that the dietary and mobility information gleaned from stable isotope analysis can be used to interpret the lifeways of archaeological peoples. ?
74

Ecological and Phenotypic Divergence among Ornate Tree Lizard (<i>Urosaurus ornatus</i>) Color Morphs in Response to Environmental Variation

Lattanzio, Matthew S. 10 June 2014 (has links)
No description available.
75

Genetic Diversity, Inbreeding and Diet Variation in an Endangered Rattlesnake, the Eastern Massasauga (Sistrurus c. catenatus)

Chiucchi, James Ernest, Jr 20 October 2011 (has links)
No description available.
76

Mobility, Exchange, and Tomb Membership in Bronze Age Arabia: A Biogeochemical Investigation

Gregoricka, Lesley Ann 15 December 2011 (has links)
No description available.
77

Factors influencing the marine spatial ecology of seabirds : implications for theory, conservation and management

Grecian, William James January 2011 (has links)
Seabirds are wide-ranging apex-predators and useful bio-indicators of marine systems. Nevertheless, changes are occurring in the marine environment, and seabirds require protection from the deleterious effects of climate change, fisheries, pollution, offshore development, introduced predators and invasive species. The UK supports internationally important populations of seabirds but also has vast wind and wave resources, therefore understanding how seabirds use the marine environment is vital in order to quantify the potential consequences of further exploiting these resources. In this thesis I first describe the range of wave energy converting devices operational or in development in the UK, and review the potential threats and benefits these developments may have for marine birds. I then synthesise data from colony-based surveys with detailed information on population dynamics, foraging ecology and near-colony behaviour, to develop a projection model that identifies important at-sea areas for breeding seabirds. These models show a positive spatial correlation with one of the most intensive at-sea seabird survey datasets, and provide qualitatively similar findings to existing tracking data. This approach has the potential to identify overlap with offshore energy developments, and could be developed to suit a range of species or whole communities and provide a theoretical framework for the study of factors such as colony size regulation. The non-breeding period is a key element of the annual cycle of seabirds and conditions experienced during one season may carry-over to influence the next. Understanding behaviour throughout the annual cycle has implications for both ecological theory and conservation. Bio-logging can provide detailed information on movements away from breeding colonies, and the analysis of stable isotope ratios in body tissues can provide information on foraging during the non-breeding period. I combine these two approaches to describe the migration strategies of northern gannets Morus bassanus breeding at two colonies in the north-west Atlantic, revealing a high degree of both winter site fidelity and dietary consistency between years. These migratory strategies also have carry-over effects with consequences for both body condition and timing of arrival on the breeding grounds. Finally, I investigate the threats posed to seabirds and other marine predators during the non-breeding period by collating information on the distributions of five different species of apex predator wintering in the Northwest African upwelling region. I describe the threat of over-fishing and fisheries bycatch to marine vertebrates in this region, and highlight the need for pelagic marine protected areas to adequately protect migratory animals throughout the annual cycle. In summary, the combination of colony-based studies, bio-logging, stable isotope analysis and modelling techniques can provide a comprehensive understanding of the interactions between individuals and the marine environment over multiple spatial and temporal scales.
78

Foraging Ecology and Stress in Sea Turtles

Chelsea E Clyde-Brockway (6823772) 13 August 2019 (has links)
As ectothermic marine megafauna, sea turtle physiology and ecology are tightly intertwined with temperature, seasonality, and oceanography. Identifying how turtles respond when exposed to cold water, how they adapt to cold environments when they need to explore cold environments in order to forage, and what foraging resources are exploited by sea turtles are all components central to their conservation. Cold-stunning is a well-documented phenomenon that occurs when water induced decreases in sea turtle body temperature cause turtles to become immobilized and wash ashore. While most cold-stunned turtles are rescued and rehabilitated, we do not know whether cold-stunning is an acute transient occurrence, or a symptom of a bigger environmental problem. Further, while in some environments avoiding cold water is preferential, in other habitats, sea turtles need to inhabit cold environments in order to forage. Along the Eastern Pacific Rim, discrete upwelling locations are characterized by high primary productivity and unusually cold water. In these environments, avoidance is not possible and sea turtles require physiological adaptions to mitigate body temperature decreases in cold water. Little is known about how turtles handle upwelling environments, despite the fact that sea turtles remain in these habitats regardless of water temperature fluctuations. Because upwelling habitats provide increased nutrient presence, and sea turtles are opportunistic foragers, quantification of diet composition will further our understanding of why sea turtles remain in cold water environments year-round. Diet composition in multiple populations of cohabitating sea turtles revealed partitioning that results in reduced inter-specific competition. Further, flexibility in diets provides a wide range of ecosystem services central to habitat resiliency. Therefore, conservation of endangered sea turtles requires complete ecosystem conservation, and complete understanding of the interconnectivity of sea turtles and their environments is crucial.<br>
79

Habitat selection and food-web relations of Horned Grebes (Podiceps auritus) and other aquatic birds on constructed wetlands in the Peace Parkland, Alberta, Canada

Kuczynski, Eva C Unknown Date
No description available.
80

Habitat selection and food-web relations of Horned Grebes (Podiceps auritus) and other aquatic birds on constructed wetlands in the Peace Parkland, Alberta, Canada

Kuczynski, Eva C 11 1900 (has links)
I investigated if constructed wetlands provide breeding habitat for the Horned Grebe (Podiceps auritus) in northwest Alberta. Over two years, I conducted bird surveys of 201 borrow-pits (ponds created during road construction) and 18 natural wetlands and collected data on local habitat and landscape features. For subsets of ponds, I also collected water chemistry and invertebrate data, and conducted stable isotope analysis. Grebes occurred on 36% of borrow-pits and produced chicks on 61% of occupied sites in 2007 and 81% in 2008. Grebes occurred more frequently on larger ponds, with more emergent vegetation, and avoided forested ponds that supported beaver activity. Horned Grebes are generalist foragers that did not select nesting ponds based on food-web structure. Twenty-six other bird species used borrow-pits, with distinct assemblages occurring on agricultural versus forested ponds. My study indicates that wetland construction offers a viable method for creating habitat for Horned Grebes and other species. / Ecology

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