Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 32 for “"geographic ranges"”.
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A landscape approach to forecasting climate change impacts on geographic ranges and phenologies of plants in the Washington Cascades
… ecological processes that maintain the geographic range limits of plants, focusing on the role of climate and disturbance in setting contemporary range limits and mediating the response of those ranges to a warmer climate. As a study system, we used two species of yellow monkeyflower …
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Early Life History Stage Dynamics Across the Elevational Ranges of Andean Trees
… one option species have is to shift their geographic ranges to respond to changing temperatures, precipitation, and other climatic variables. Accurately predicting how species distributions may shift with climate change requires an understanding of what controls species ranges that extends …
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Phylogenetics, biogeography, and climate niche variation of South Pacific and Hawaiian Psychotria
<p>Why do some species have broad geographic distributions, while other species are confined to a narrow distribution? Species age, ecological niche, or dispersal traits may help explain why some insular species are abundant and found on many islands, while others are rare and restricted to one …
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Increased phenotypic plasticity linked to broader geographic range size in sunflower (Helianthus) species
… five Helianthus species representing different geographic ranges. Locally restricted H. longifolius and H. verticillatus showed less plasticity in growth and allocation traits than widespread H. angustifolius and H. maximiliani. Rare species with narrower ranges also displayed less …
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The phylogeography of the short-tailed shrews (genus Blarina) of southeast Tennessee
… and Blarina carolinensis. To clarify their geographic ranges, Blarina vouchers were collected throughout the study area and mitochondrial DNA cytochrome b genes were isolated and sequenced. I collected and compared 53 DNA sequences from shrews throughout southeast Tennessee and southwest …
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Temporal changes in unisexual and sexual Ambystoma salamander populations in southeast Michigan
<p>Climate change drives changes in organisms’ geographic ranges that can lead to shifts in population structure. Unisexual (all female) <em>Ambystoma</em> salamanders reproduce via kleptogenesis, resulting in ploidy-variable offspring. I analyzed genetic data of historic and modern-day unisexual …
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Geographic range dynamics of South Africa's bird species
… in species conservation is a knowledge of the geographic ranges of species, and how these are changing through time. For birds there is a special opportunity to undertake studies of range changes, making use of the data collected by the First and Second Southern African Bird Atlas Projects …
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DETECTION AND OCCURRENCE OF NERODIA HARTERI (SERPENTES: COLUBRIDAE) IN AN UPPER PORTION OF THE BRAZOS RIVER WATERSHED
… natricines with one of the most restricted geographic ranges in North America. I quantified detection and site occupancy probabilities of <em>N. harteri</em> and its sympatric congeners (<em>N. erythrogaster</em> and <em>N. rhombifer</em>), as well as microhabitat selection within the …
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Introgression, Population Structure, and Systematics of the Sphagnum capillifolium complex
<p>How geographical distance and historical events affect patterns of population divergence and gene flow is an important question in evolution and biogeography. Sphagnum subgenus Acutifolia is one of the four major subgenera of Sphagnum peatmoss comprising numerous species with broad geographic …
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Tertiary marine prosobranchs: larval dispersal and geographic range
… marine invertebrate species to establish great geographic ranges; several studies along a single margin of an ocean basin have supported this proposal (Shuto, 1975; Hansen, 1978). This study makes use of the fossil record to examine larval dispersal patterns on a larger geographic scale: across …
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Hyperspectral Reflectance and Stable Isotopic Nitrogen: Tools to Assess Forest Ecosystem Nitrogen Cycling
… utilizes study sites located throughout the geographic ranges of Douglas-fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda) to explore relationships between hyperspectral remote sensing, N stable isotope ratios ("15N) and growth response to nitrogenous fertilizer. In both species …
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Aligned selection in cold climates breaks the rules of trade-offs in adaptation
… (coldward vs warmward), migratory behaviour and ranges, the age and body size of the pair, and the temperature at which species experience divergent temperatures. Overall, we found that trade-offs are widespread under some conditions, including among pairs experiencing climatic challenge in …
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A response surface investigation of the larval tolerances of three spionid polychaetes to temperature, salinity and food concentration
… and B. columbiana which occupy nearly identical geographic ranges. The other was Polydora giardi a common coinhabitant with B. columbiana. In addition a third independent parameter, food concentration, was added to the study of B. columbiana and P. giardi.</p> <p>The larvae of the two Boccardia …
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Interference with biologic transmission of Anaplasma marginale by targeting the tick-pathogen interface
… hosts. Because of the expansion of the geographic ranges of both ticks and pathogens, increasing tick populations, emerging tick-borne pathogens and continued challenges of achieving effective and sustained tick control, ticks and tick-borne diseases have increased in importance from …
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THE EVOLUTIONARY ECOLOGY OF HOST-MICROBIOME SYMBIOSIS IN ONTHOPHAGUS DUNG BEETLES
… changes when hosts are introduced to novel geographic ranges. As a whole, my dissertation employs a diversity of methodologies to better understand the evolutionary and ecological ramifications of dung beetle microbiome symbioses.
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A Global GIS Analysis of Primate Diversity and Biogeography: Assessing Trends in Habitat Loss and Extinction Risk to Inform Primate Conservation
… tropical forest loss within primate species ranges. The loss of tropical forests within primate species ranges between 2000-2020 was quantified using Google Earth Engine. Rates of forest loss were found to have increased in all realms, with Madagascar experiencing the greatest total relative …
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Environmental Factors Affecting the Landscape-Scale Spatio-Temporal Distribution of Small Mammal Assemblages Across the Northern Great Plains of North America
… of grassland small mammals within their geographic ranges, while annual weather variation would largely influence the temporal dynamics of grassland rodents across the landscape. I found soil texture was the primary landscape feature driving small mammal composition across my study area, …
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Examining neotropical primate community structure at regional and local scales : insights from taxonomic and phylogenetic approaches
… I investigate the variation within species ranges in relation to species richness and patterns of species relatedness. Results suggest positive associations among species throughout their distributions, whereby species tend to present higher richness within their ranges than average richness …
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Assessing predictive performance and transferability of species distribution models for freshwater fish in the United States
… was also higher for species with large geographic ranges and small local populations. Species prevalence affected discrimination power in the model training but not in the validation. In chapter 3, spatial transferability of SDMs was low for over 70% of the 21 species examined. Only 24% …
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Investigations of physiological and competitive relationships of Elymus species related to establishment in the Great Basin, USA.
… and Elymus multisetus because they have wide geographic ranges and have been identified as good competitors against Bromus tectorum. Results from the first study indicate that different Elymus seed sources had few differences in their physiology and resource acquisition. Bromus tectorum …
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