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 15 of 15 for “"Density dependent mortality"”.
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A test of the variable nature of density-dependent mortality in fish populations
… in power-plant cooling systems was questioned. Density-dependent dynamics were hypothesized as variable, not constant, making previous analyses based on constant density-dependent or density-independent mortality in error. This hypothesis was tested with a simulation model based on complex …
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Forest Mortality in Lake Tahoe Basin from 1985-2010: Influences of Forest Type, Stand Density, Topography and Climate
Widespread and synchronous outbreaks of forest mortality during the 1990s and continuing to present day have drastically altered millions of hectares of forestlands from Mexico to Alaska (Bentz 2009). Tree mortality is a complex process with a variety of both exogenous and endogenous factors …
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On the economic optimality of marine reserves when fishing damages habitat
… fishing effort may directly increase individual mortality rates. Second, fishing effort may increase competition between individuals, thereby increasing density-dependent mortality rates. I then optimize effort distribution and fish stock density according to three management cases: (1) a sole …
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On the economic optimality of marine reserves when fishing damages habitat
… fishing effort may directly increase individual mortality rates. Second, fishing effort may increase competition between individuals, thereby increasing density-dependent mortality rates. I then optimize effort distribution and fish stock density according to three management cases: (1) a sole …
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Resistance management of western corn rootworm (Coleoptera: Chrysomelidae) in transgenic Bt maize
… A field study was used to quantify how larval density-dependent mortality of western corn rootworm in Bt and non-Bt maize impacts calculations of mortality imposed by Bt traits. A second field study was used to evaluate the use of a soil-applied insecticide with Bt maize to reduce feeding …
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The Role That Asexual Reproduction Plays in the Regeneration of Tropical Piper Shrubs: Habitat Differences and Genetic Consequences
… of somatic mutations, habitat heterogeneity, and density dependent mortality, may be playing an important role in maintaining genetic diversity, despite high levels of asexual recruitment. I also integrated spatial geographic data with spatial genetic data and found that more than 50% of …
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Interactions among tree species and pathogen-suppressive bacteria in tropical forest soils
… negative plant-soil feedbacks and promoting density-dependent mortality of seedlings close to parent trees. Pathogens interact with a myriad of other organisms in soil that have the potential to moderate plant disease and in turn its effects on community composition. Studies that consider …
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The Impact of Neighborhood-Based Processes on Demography and a Decline in Species Diversity in a Temperate Deciduous Forest
… the maintenance of species diversity, including density-dependence, interspecific competition, and disturbance, should be able to elucidate not only the causes of the maintenance of species diversity, but also its decline. This study investigated how these three processes contributed to a decline …
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Evolutionary Ecology of the First Animal Ecosystems
… In Chapter 3, I also find evidence for negative density-dependent mortality between heterospecifics in several communities, which suggest neutral dynamics and could be the consequence of processes such as scramble competition or disease. In Chapter 4, I find evidence of mixed reproductive …
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Modeling maximum size-density relationships of loblolly pine (Pinus taeda L.) plantations
… quantifies the reduction in tree numbers due to density-dependent mortality. Maximum size-density relationships (MSDRs) are a component of self-thinning that describe the maximum tree density per unit area obtainable for a given average tree size, often quadratic mean diameter (D). An MSDR …
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Stochastic modelling of nutrient and predator-prey populations
… not only the growth rate of prey and the density-dependent mortality rate of predator, but also the quadratic mortality rates of the two species and the capturing rate of predator are perturbed by the stochastic noise. Then we study how the correlations between the Brownian motions affect …
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Refining monitoring practices and applying novel enhancement strategies to populations of threatened diadromous species.
… of these two methods showed a high degree of density-dependent error in abundance estimates from time-delineated surveys. Further analysis showed that the area covered during time-delineated electrofishing surveys is highly variable, leading to imprecision around abundance estimates. The …
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The role of life history traits for coexistence and forest recovery after disturbance – a modelling perspective. Towards a better understanding of species-rich forests
… the role of tree life history traits (growth, mortality and recruitment) on different processes structuring species-rich forests. Our study system is a montane rainforest located in the Tropical Andes hotspot of biodiversity in southern Ecuador. Here, we find a mosaic of steep ridges and deeply …
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From data to mathematical analysis and simulation in models in epidemiology and ecology
… a fixed duration. If each host is subjected to density-dependent mortality in its larval stage, we obtain explicit conditions for coexistence of both hosts, as long as each 1 host-parasitoid system would tend to an equilibrium point. Otherwise, if mortality is density-independent, under the same …
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Behavioral ecology of coral reef fishes at spawning aggregation sites
… risks, showing responses designed to reduce the mortality of propagules and adults. Dusk-spawning species generally did not respond to changes in flow direction and predator abundance, most likely due to their short spawning periods and the reduced predatory pressures that occurred at dusk. Tides …