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 23 for “"Niche differentiation"”.
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METABOLIC SHIFT AND NICHE DIFFERENTIATION DURING DENITRIFYING PHOSPHORUS REMOVAL IN A TROPICAL CLIMATE
This work aims to increase current knowledge of microbial communities and their metabolic underpinnings in EBPR processes under tropical conditions. Aerobic granulation and alternating carbon sources were used to obtain Accumulibacter enrichment at 30&176C. It was surmised that involvement of …
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Niche differentiation in savannas : exploring competition-based hypotheses for inter-life form coexistence
… possible if trees and grasses occupy different niches when exploiting limited resources such as water and nutrients. I investigated two competition-based models, each of them considering a different axis for niche separation: the two-layer hypothesis, which is based on differences in rooting …
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Investigation of Factors Influencing Niche Differentiation of Ammonia-oxidizing Archaea and Bacteria in Freshwater Environments
… environmental factors that influence the niche differentiation of AOA and AOB from freshwater environments. In order to investigate factors that drive the diversity of freshwater AOB communities, we enriched AOB from lakes representing a range of trophic states. The resulting enrichments …
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Comparative whole genome transcriptional responses of Ruminococcus albus strain 7 and 8: a case for specialization and niche differentiation
Ruminococcus albus strains are one of dominant fibrolytic bacteria in the rumen that contribute to plant biomass as well as vitamin utilization in host nutrition. To better understanding of host-microbe interactions, it is relevant to establish the model for fiber degradation and vitamin metabolism …
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Weed versus wildflower : mating system ecology in a Taraxacum native-exotic contact zone
… levels are often associated with mating system differentiation, especially in genera capable of clonal seed production through apomixis, which are derived from ancestral sexual lineages. The evolution of apomixis and associated changes in ploidy level contributes to niche differentiation and …
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Coexistence and resource use in space and time in a West African tortoise beetle community
… explain community organization with a strict niche separation and specialization of the single species, achieved mainly by interspecific competition and consecutive resource partitioning. Recent non-equilibrium or stochastic models see stochastic factors ("intermediate disturbances") as more …
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Intraspecific trait variation and community assembly in old-field grasslands
… for evidence of environmental filtering and niche differentiation based on trait dispersion patterns, with or without accounting for intraspecific trait variation. The tests provided evidence of strong trait-based environmental filtering and weak niche differentiation, and these patterns were …
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Examining neotropical primate community structure at regional and local scales : insights from taxonomic and phylogenetic approaches
… complex relationships. At local communities, niche differentiation is expected to allow species coexistence. However, these differences may reflect evolutionary constraints of species, rather than active selection. I investigated niche overlap and presence of niche conservatism for primate …
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Diversity and biogeography of Madagascan bryophytes with an analysis of taxic and functional diversity along an elevational gradient in Marojejy National Park
… environments and how habitat filtering and niche differentiation influence bryophyte assemblages along an elevational gradient. The bryoflora of Madagascar, with its 1188 species and infraspecific taxa is relatively rich and highly diversified. Along the Marojejy elevational gradient, 254 …
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Effects of competition, disturbance and productivity on the dynamics of inducible trophic polymorphism in tetrahymena vorax
… Cannibalism here indicates an extreme case of niche differentiation and resource utilization via phenotypic plasticity and significantly affects the dynamic equilibrium of T. vorax’s three morphs. By manipulating productivity level, disturbance frequency and the presence or absence of an …
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Diversity of the marine cyanobacterium Trichodesmium : characterization of the Woods Hole culture collection and quantification of field populations
… coexist, Trichodesmium spp. may occupy different niche spaces through differential utilization of resources such as nutrients and light, and through responses to physical characteristics such as temperature and turbulence. To investigate niche differentiation in Trichodesmium, I characterized …
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DIET ANALYSIS OF NATIVE AND NON-NATIVE JUVENILE SALMONIDS IN A LAKE SUPERIOR TRIBUTARY
… single prey item in common. Results suggest that niche differentiation has occurred among the three fish as indicated by the low diet overlap index values between interspecific pairings of FSCs and differences in the selectivity values for the most common prey items in the drift and diet among the …
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Diversity of the marine cyanobacterium Trichodesmium : characterization of the Woods Hole culture collection and quantification of field populations
… coexist, Trichodesmium spp. may occupy different niche spaces through differential utilization of resources such as nutrients and light, and through responses to physical characteristics such as temperature and turbulence. To investigate niche differentiation in Trichodesmium, I characterized …
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An Integrated Approach to Improving Efficiency in Photosynthetic Microbial Systems
… the mat community, and suggested approaches for niche differentiation between phototrophic species, as well as mechanisms for lateral gene transfer and biogeographic dispersal. In Chapter 3, the cyanobacterial enrichment culture was used to conduct growth experiments in conjunction with red light …
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Productivity, metabolism and physiology of free-living chemoautotrophic Epsilonproteobacteria
… respectively, providing a mechanism for niche differentiation in situ. To gain insights into the core biochemical reactions underlying autotrophy in Epsilonprotebacteria, a theoretical metabolic model of Sulfurimonas denitrificans was developed. Validated iteratively by comparing in …
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Productivity, metabolism and physiology of free-living Chemoautotrophic Epsilonproteobacteria
… respectively, providing a mechanism for niche differentiation in situ. To gain insights into the core biochemical reactions underlying autotrophy in Epsilonprotebacteria, a theoretical metabolic model of Sulfurimonas denitrificans was developed. Validated iteratively by comparing in …
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Ecological significance of seed traits in the genus Macaranga
According to the regeneration niche hypothesis, the transition from seeds to seedlings is critical in determining plant distribution patterns. This initial stage of recruitment may be strongly influenced by seed mass via effects on the sensitivity to light quality and soil moisture availability for …
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Functional divergence between Vachellia and Senegalia could underpin differences in invasiveness and Eltonian niche partitioning in African savannas
… and Senegalia suggest their possible ecological niche divergence, which could explain the observed differences in invasiveness between them. This thesis provides the first ecophylogenetic study to assess the level of ecological niche divergence between these economically, socioeconomically and …
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Occurrence, Composition, and Habitat Associations of Terrestrial Herbaceous Plants in a Tropical Forest Community
In tropical forests, niche differentiation in terms of resource partitioning remains a central hypothesis for the maintenance of species diversity. However, all plants require seemingly identical resources, which would appear to limit the number of niche dimensions available for species to inhabit. …
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Evolutionary patterns in Thamnochortus (Restionaceae) : a study of specification in the Cape floristic region
… to determine area relationships. The primary differentiations on the general area cladogram of areas of similarity distinguished a summer rainfall region (south coast) from a winter rainfall region (south Western Cape extending up the west coast). Within the winter rainfall region there is …
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