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 85 for “"Environmental variation"”.
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Environmental variation and life-history evolution: experiments on Caenorhabditis remanei
… influence the responsiveness of populations to environmental change. In order to approach this question I used a model species (Caenorhabditis remanei) and selection experiments in the laboratory. Caenorhabditis species are widely used in research, for instance, to study mechanisms affecting …
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Cross-scale assessment of environmental variation on RABV reservoir Desmodus rotundus
… origin. This dissertation demonstrated how environmental variation associated with human activity may impact D. rotundus at the population level, the impacts of landscape factors on spillover transmission risk, and the broader climatic drivers of host distribution across a continent. In …
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Trait-based approaches to understanding the response of forest understory herbs to environmental variation
… and communities will respond to future environmental change. Trait-based approaches can thus offer valuable insights into how populations and communities will respond to environmental change by providing a mechanistic link between plant traits and the environment. This dissertation …
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Ecological responses by Mexican spotted owls to environmental variation in the Sacramento Mountains, New Mexico
Understanding the influence of environmental variation on population processes is a fundamental requisite for devising strategies that conserve species. A common tactic for conserving raptor populations is to maintain or manipulate habitat conditions that maintain or increase availability of prey …
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Influence of Diet and Environmental Variation on Physiological Responses of Juvenile Pallid Sturgeon (Scaphirhynchus albus)
… pallid sturgeon are locally adapted to regional environmental conditions, I conducted a common-environment experiment using individuals from two genetically distinct source populations. I measured absolute growth, food consumption, feed conversion efficiency and routine metabolic rate of pallid …
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The role of genetic and environmental variation in the respiratory phenotype of alpha 1 antitrypsin deficiency
… interactions between multiple genetic and environmental factors. This thesis will describe the COPD phenotypes observed in AATD and their inter-relationships, forming the basis for examining phenotypic associations with specific candidate genes and HLA class II type. Finally it examines the …
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Linking environmental variation across the Scottish Highlands with red deer (Cervus elaphus) trace element status, parasite burden, and skeletal morphometry
… have extensively quantified geographic variation in parasite prevalence or nutritional essential and non-essential trace/macro and toxic element status. Given the well-recognised effects of sub-lethal parasitism and sub-optimal nutrition on performance of ruminants (from an agricultural …
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Influence of environmental variation on habitat selection, life history strategies and population dynamics of sympatric ptarmigan in the southern Yukon Territory
Climatic variation is an important driver of avian life history and population dynamics. Climate change models predict increased variability for many regions and to predict the effects on species, we need to examine how their life history characteristics influence their response to climate. I …
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Distribution and abundance of Cape hakes (Merluccius capensis and Merluccius paradoxus) in relation to environmental variation in the Southern Benguela system
… distribution and abundance are related to ocean environmental conditions (including bottom temperature, bottom oxygen concentration, sea surface temperature and sea surface minus bottom temperature, as a measure of stratification or mixing) and location (including longitude, latitude and bottom …
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Mixed-Silver Maple Forests Of The Upper Mississippi River Floodplain: Variations In Composition, Structure, And Growth Along Environmental Gradients
… specifically aspects of hydrology. The role of environmental variation in overstory composition, structure, and growth is not well documented. Goals of this study were to 1) characterize current stand conditions along gradients of inundation and relative elevation, and 2) describe growth …
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Community ecology of aquatic insects in forested headwater streams in the southern Appalachians
… Niche assembly emphasizes the role of environmental gradients as filters that organize a metacommunity by locally selecting colonizers with similar functional traits, whereas dispersal assembly emphasizes the importance of source pool characteristics and dispersal limitation in …
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Variation in Thamnocortus insignis - genetically and environmentally plastic?
Environmental variation of Thamnocortus insignis Mast. (Restionaceae) is presented, by using average dry weight measurements of six populations of this species found along the coast of the Cape Province. The dry weight measurements were used to detect variation in the growth rates of the six …
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A Resource-Based Perspective of Growth Through Strategic Change: A Longitudinal View
… that can be altered based upon the direction of environmental variation. The path direction is theoretically linked to the concept of a resource based life cycle. It is interesting to conjecture if this resource-based life cycle path exists in other industries that have been deregulated. The …
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Assessing wildlife habitat suitability for ecological sites and state and transition models
… managers in understanding how management and environmental variation affects habitat suitability. Ecological site descriptions (ESDs) have the potential to fill this role because they contain information on the biophysical features of the land and contain state-and-transition models (STMs) …
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Separation of alkali metal cations and alkaline earth cations using ionizable crown ethers
… were utilized to probe the effects of structural variation within the ionizable polyether and environmental variation upon the selectivity and effÃciency in metal ion complexation and transport. Experimental techniques of pK^ determination in dioxane-water systems, solvent extraction, and …
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FUNCTIONAL DISSECTION OF ADIPOKINETIC HORMONE PRODUCING CELLS
… metabolic homeostasis in light of significant environmental variation in food availability are not completely understood. In Drosophila, the mobilization of energy is primarily controlled by the endocrine factor Adipokinetic Hormone (AKH). AKH function is critical for proper energy allocation …
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Morphological, Genetic, and Ecological Insights into the Puerto Rican Tody: Investigating Variation Between and Within Dry Forest and Rainforest Populations
Environmental variation plays an important role in shaping how species persist and adapt, particularly on islands—isolated areas where ecological conditions can vary dramatically over short distances, and anthropogenic pressures are often intensified. These factors contribute to conditions where …
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The effects of invasive European Buckthorn (Rhamnus cathartica) on soil microbial community composition
… small relative to other sources of spatial and environmental variation, and that observed microbial differences between buckthorn-invaded and uninvaded soils reflects environmental variation that pre-dates buckthorn invasion.
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Biogeography and ecology of African waterbirds
… and varies latitudinally. Spatia-temporal variation in habitat availability and quality are the primary factors which control waterbird distribution, and the dynamic nature of waterbird dispersion is an adaptation to dramatically fluctuating habitats. About 69% o£ the variance in African …
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The evolution and ecological genetics of pupal color dimorphism in swallowtail butterflies (Lepidoptera: Papilioninae)
Data bearing on the evolution, environmental control and genetic basis of pupal color dimorphism was presented or discussed for six species of swallowtail betterflies. Papilla glauces and P. cresphontes produce only brown pupae while P. polyxenes, P. troilus, Battus philenor and Eurytides marcellus …
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