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 “"beta diversity"”.
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Modelling spatial turnover patterns in tree species diversity for conservation
The planet’s biodiversity is increasingly threatened by the effects of rapid environmental change. Biodiversity loss led by expanding anthropogenic activity, combined with the effects of changing climatic regimes, pose a threat to natural communities and the ecosystem services that they underpin. …
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MICROBIAL GUARDIANS OF THE SAVANNAH: UNRAVELING THE GUT MICROBIOME FOR AFRICAN CARNIVORE CONSERVATION
… analyzed. No significant differences in alpha or beta diversity were detected between preserved and dried samples, although bacterial beta diversity differed between preserved and opportunistic samples (PERMANOVA). Core bacterial communities remained consistent across sample conditions, supporting …
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Consequences of drought, flooding, and insect herbivory on the distributions of closely related willow and poplar (Salicaceae) species across hydrologic gradients in Minnesota wetlands
Understanding the mechanisms underlying species diversity patterns is a central and long-standing issue in ecology. Beta diversity, the variances in species composition among sites, is an important aspect of species diversity that links local diversity patterns to regional diversity patterns. One …
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Taxonomic homogenization of plant communities in Illinois wetlands and the role of wetland compensation
Biotic homogenization, a process by which β-diversity erodes, represents a severe threat to biodiversity. Wetlands are especially susceptible to biotic homogenization; however, this process has rarely been documented and represents just one of many possible outcomes of compositional change. …
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Strong Interactive Species in Metacommunities: The Interaction Between Dispersal and Daphnia magna in Zooplankton Communities
… a species that affects community structure and diversity, and to the best of my knowledge, the interaction between dispersal and strongly interactive species has not been directly addressed experimentally. In the following study, I investigated the interaction of dispersal and a strong …
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Distribution Patterns and Taxonomy of Freshwater Ascomycetes Along the Florida Peninsula
… analysis, Sorenson's similarity index and beta diversity reveal that the freshwater ascomycete community composition differs along the temperate-subtropical ecotone of the Florida peninsula. Ordination analysis shows that pH might also be an important factor in the distribution patterns of …
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Brain-Body Crosstalk: Characterizing the Gut Microbiome in Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder
… ethnicity) revealed significant differences in beta diversity (p < 0.05). Between-individual comparisons found significant differences in alpha (p = 0.0336) and beta diversity (p = 0.001) between ASD, ADHD and comorbid ASD/ADHD diagnoses however no significant differences across behavioural …
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Microbiome Dynamics in Broilers Infected with Infectious Bronchitis Virus and the Protective Role of Lactobacillus-Based Probiotics
… compared to control. Significantly higher alpha diversity indexes including observed Operational Taxonomic Units (OTUs) and Shannon was observed in IBV challenged group compared to control in cecum at 6 and 15 dpi, whereas tracheal microbiome of IBV challenged group showed significantly higher …
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The Vaginal Microbiome Related to Reproductive Traits in Beef Heifers
… the number of observed OTUs were used as alpha-diversity measures resulting in no significant differences in fecal samples (P = 0.95, P = 0.66) and significant differences for vaginal samples due to pregnancy status and/or time (P = 0.0056, P = 0.0015). No differences in beta-diversity were seen …
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Natural patterns and anthropogenic disturbance in north Adriatic marine benthic assemblages: descriptive and methodological studies
… of a large area in the North Adriatic Sea. Beta diversity is a measure of the variability in species composition, and Whittaker’s index has become the most widely used measure of beta-diversity. However, application of the Whittaker index to soft bottom assemblages of the Adriatic Sea …
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The role of sampling location and depth in the performance of lake plant environmental DNA metabarcoding
… DNA (eDNA) methods permit broad yet detailed biodiversity sampling to be performed with minimal field effort, but uncertainty remains regarding the spatial resolution necessary for effective sampling. We analyze eDNA samples from twelve temperate lakes via ITS1 rRDNA metabarcoding for aquatic and …
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The association of prematurity and medical conditions with the gut microbiome of mammals
… (q-value=0.0004) of the variance in microbial beta diversity but that there was no significant effect of early-life nutritional supplementation on the microbial diversities of preterm lambs. However, prematurity per se explained 5.7% (q-value=0.024) of the variance in microbial beta diversity …
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Vegetation, diversity and rarity on the Cape Peninsula, South Africa
… is characterised by the combination of a diversity of habitats supporting a mosaic of vegetation types. This study attempts describe. and explain some of the determinants of species pattern and distribution. The first part of the thesis compares a simple vegetation classification, derived …
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Patterns of temporal changes in species composition and diversity in island ecosystems
Patterns of spatial and temporal changes in biodiversity, natural or anthropogenic, and their importance in understanding the dynamics and restoration of natural ecosystems, have long been among the major questions in ecology. These changes are rather important to be understood in the early stages …
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Altered Vulvar Microbiomes in Vulvar Lichen Sclerosus
… Shannon index was used to quantify alpha diversity. Unweighted UniFrac (bacteria) and Bray-Curtis dissimilarity (fungi) were used to quantify beta diversity. Relative abundance testing was performed at sites with significant community structural alterations using Linear discriminant …
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The effects of prebiotics on the growth performance and gastrointestinal microflora modulation in oreochromis mossambicus in Hardap region, Namibia
… discovered that I group showed higher alpha and beta diversity indexes in comparison to the control and inulin + mushroom groups. Typical examples of phyla identified include Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes. At the genus level, relative abundance showed higher …
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Benign, potentially malignant & malignant oral lesions; an analysis of oral and gut microbiota
… for oral malignancy. We looked at alpha diversity, beta diversity, taxonomy, differential abundance, and functional profiling. Results: Our results showed distinct gut microbial profiles between benign and malignant groups and the association of specific microbes in oral saliva, such as …
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Caracterização da microbiota intestinal, perfil inflamatório e integridade da barreira gastrointestinal de crianças diagnosticadas com transtorno do espectro autista
… gene analysis. Relative abundance, alpha diversity, and beta diversity analyses were performed to characterize the microbiota and resistance genes, along with differential relative abundance analysis. Zonulin, Claudin, and Occludin concentrations were analyzed from fecal samples. The …
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Abyssal polychaete assemblages along latitudinal gradients of productivity in the equatorial Pacific and North Atlantic Oceans
Patterns in polychaete abundance, body size and diversity were investigated at 12 sites between 4300 and 5000 m in the central Pacific and the north-east Atlantic. In the central Pacific, three of the sites (EqPac 0N, 2N and 5N) were observed to lie under high surface productivity regimes, and they …
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Characterizing spatial and temporal trends in fish community diversity in the inland lakes of Isle Royale, MI, USA
… providing an opportunity to explore how fish diversity has natural shifted with minimal confounding effects. I analyzed fish assemblages of 23 lakes sampled in the 1920s, 1990s, and 2020s to 1) assess temporal shifts in species richness and composition 2) identify lakes and species …
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