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 193 for “"Herbivore"”.
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Predicting Insect Herbivore Distribution Using Climatic and Biotic Variables
… distribution in nature. The abundance of insect herbivores can vary greatly spatially and temporally. These variations can be explained by abiotic variables such as precipitation, they can also be explained by biotic variables such as nutrient availability. Here I present two field observational …
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Two-patch herbivore/vegetation models with density-dependent migration
… we constructed two mathematical models for herbivore/vegetation interactions in environment of two patches, using the metaphysiological approach and a density-dependent migrations. In the first model we considered the case when the environment is constant, and we constructed a system of four …
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Herbivore movement and spatial population dynamics in a heterogeneous landscape
… and patch quality often covary in plant-herbivore systems, and that most matrix studies have failed to experimentally or statistically isolate the effects of the matrix from potential patch quality effects on dispersal. These findings highlight the value of a mechanistic understanding of …
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Diet Breadth Evolution and Diversification of a Generalist Insect Herbivore
<p>Insect herbivores are one of the most diverse groups of multicellular organisms, and the vast majority are specialists, which feed on only a few plant species. The factors that cause some herbivores to be specialists and others to be generalists are still unclear. It is known that the selective …
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Effects of a Small Mammalian Herbivore on a Grassland Undergoing Restoration
This thesis examines the effects of the prairie vole, Microtus ochrogaster, on a grassland undergoing restoration. The study addresses these effects with respect to treatment plots (vole-enhanced enclosures and vole-excluded exclosures) and control plots, which have not had the small mammal …
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Understanding How Whole Genome Duplication in Plants Impacts Herbivore-plant Interactions
<p>Herbivory by insect herbivores is a strong selective force in many communities. Although herbivore-plant interactions have been a focus of interest for decades, we are still exploring how large-scale genetic changes in the host plant alters their interactions with insect herbivores. One such …
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Herbivore resistance in inavasive and native Myriophyllum spicatum and Myriophyllum heterophyllum
… Many attempts have been made to use augmented herbivore populations as a biological control of nuisance populations, however, the success of these efforts has been variable. One character which can affect the success of these biological controls is the expression of plant herbivore resistance. …
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Impacts of climate change on herbivore induced plant signaling and defenses
… exposure, increased susceptibility of soybean to herbivores resulting from elevated CO2 exposure was removed. This study suggests soybean in areas experiencing elevated drought will have an advantage over well-watered plants grown under elevated CO2. It is not known if the impact of elevated CO2 …
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Differential detoxification strategies in closely related herbivore species across a sharp ecotone
Herbivores face a continual challenge of balancing their nutritional needs with the toxicity that they encounter in their diets. Plants produce toxic phytochemicals to ward off herbivores, while herbivores have evolved methods of detoxifying these chemicals. One such method is the use of cytochrome …
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Patterns of association in a co-introduced insect herbivore and parasitoid wasp
… in the re-association of many exotic plant-herbivore species, but ecological fitting also readily occurs as evidenced by the prevalence of native species host switching to exotics, and vice-versa. For the remainder of my dissertation, I used molecular methods to determine the invasion routes …
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Using Sporormiella to track herbivore biomass within the Hluhluwe-Imfolozi game reserve
… fungus that only grows on the dung of herbivores. has been used to infer unknown herbivore abundances or biomass and identity periods of mega-herbivore extinction in the palaeo-record. ln Africa. however. mega-herbivores are still extant and there is therefore a unique opportunity to …
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Herbivore-plant-soil interactions in the boreal forest : selective winter feeding by spruce grouse
This thesis examines the unusual winter forage selection of spruce grouse (Dendragapus canadensis) in the Yukon. The winter diet of spruce grouse consists entirely of conifer needles. Spruce grouse feed selectively on individual trees (feeding trees) of a single species, white spruce (Picea …
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A Tale of Three Resources: The Influence of Multiple Resources on Plant-Herbivore Interactions
… role of co-limiting resources in driving plant-herbivore interactions remains poorly understood. Evidence indicates that the resources that limit plant and herbivore growth may differ which likely influences trophic interactions. In this dissertation, I explored how multiple resource limitation …
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Aboveground effects of variation in the legume-rhizobium mutualism on insect herbivore Spodoptera exigua
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-09-01 without embargo terms
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Effects of enhanced winter nutrition and climatic variation on population performance of a large herbivore
Population performance hinges on optimal allocation of available energy by individuals to competing life-history traits. Life-history strategies of long-lived, iteroparous mammals often involve prioritizing energy allocation to adult survival over any single reproductive event, therefore maximizing …
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Carbon based secondary metabolites in African savanna woody species in relation to anti-herbivore defense
Chemical defense in African savanna woody species have been inferred from foliar condensed tannin and total phenolic concentrations. However these measures are controversial since condensed tannin chemical heterogeneity compromises its simple quantification and total phenolics, which is a measure …
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Quantifying Ungulate-Rangeland Interactions: From Monitoring Free-Roaming Horse Condition to Vegetation Response Following Herbivore Exclusion
Reliable assessment of herbivore condition and vegetation response is essential for understanding grazing impacts across arid rangelands. This thesis integrates two complementary studies that address these challenges at different scales. The first develops and validates a quantitative framework for …
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Impact of Large Herbivore Use in Meadows on Lentic Function, Wetland Extent and Vegetation Hydric Status
… extent. This study sought to assess how large herbivore use in meadows may impact riparian plants needed for or leading to lentic functions and related wetland extent (in relation to potential meadow size) and vegetation hydric status (wetness). We examined wild horse and livestock grazing …
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