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Phylogenetics, Biogeography, And Climate Niche Variation Of South Pacific And Hawaiian Psychotria, Elaine Zhang
Phylogenetics, Biogeography, And Climate Niche Variation Of South Pacific And Hawaiian Psychotria, Elaine Zhang
Master's Theses
Why do some species have broad geographic distributions, while other species are confined to a narrow distribution? Species age, ecological niche, or dispersal traits may help explain why some insular species are abundant and found on many islands, while others are rare and restricted to one island. In this study, I inferred a robust, time-calibrated phylogeny of the Hawaiian Psychotria, using two nuclear and eight chloroplast loci, sampling 67 individuals. I coupled my phylogenetic hypothesis with climatic data, ecological niche modeling, and morphological dispersal characteristics to explain the variation in number of islands occupied by each species. My inferred phylogeny …
Small-Scale Biogeographic Patterns Of Benthic Bacterial And Ciliate Communities In The Saline Ponds Of Lake Macleod, North-Western Australia, Christopher Kavazos
Small-Scale Biogeographic Patterns Of Benthic Bacterial And Ciliate Communities In The Saline Ponds Of Lake Macleod, North-Western Australia, Christopher Kavazos
Theses: Doctorates and Masters
This biogeographical thesis tests for the presence of taxa-area and distance-decay relationships, which are common among macrobionts, in prokaryotic (bacterial) and micro-eukaryotic (ciliate) communities. Microbial biogeographical patterns may be distinct because of the high abundances, diversity and dispersal capabilities of microbes, in comparison to macrobionts. The Northern Ponds of Lake MacLeod, north-western Australia, provide an ideal location to address this topic, because the ponds are effectively hydrogeomorphologically identical, other than in surface area, and biotic histories can be assumed to differ only according to distance of separation. This means that hypotheses concerning species-sorting and neutral processes on microbial assemblages can …
The Biotic Effects Of Tertiary Geoclimatic Change In The Southern Hemisphere, Stuart Val Nielsen
The Biotic Effects Of Tertiary Geoclimatic Change In The Southern Hemisphere, Stuart Val Nielsen
Electronic Theses and Dissertations
I explore how pre-Quaternary geoclimatic phenomena and geographical heterogeneity influenced sub-continental speciation processes and contemporary biogeographic patterns across the Southern Hemisphere, with particular focus on two regions that have experienced elevated levels of ongoing aridification – sub-Saharan (particularly Southern) Africa and Australia. I used standard methods from the molecular phylogeneticists’ toolbox (e.g. tree building using maximum likelihood and Bayesian approaches, haplotype networks, uncorrected p-distances) combined with environmental niche modeling, morphometric principal components and fossil calibrated molecular dating analyses in order to ascertain the role that Miocene geo-climatic events played in promoting lineage accumulation and diversification through time. I found a …