Browsing UAF Graduate School by Subject "Canada, Western"
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Bayesian predictive process models for historical precipitation data of Alaska and southwestern CanadaIn this paper we apply hierarchical Bayesian predictive process models to historical precipitation data using the spBayes R package. Classical and hierarchical Bayesian techniques for spatial analysis and modeling require large matrix inversions and decompositions, which can take prohibitive amounts of time to run (n observations take time on the order of n3). Bayesian predictive process models have the same spatial framework as hierarchical Bayesian models but fit a subset of points (called knots) to the sample which allows for large scale dimension reduction and results in much smaller matrix inversions and faster computing times. These computationally less expensive models allow average desktop computers to analyze spatially related datasets in excess of 20,000 observations in an acceptable amount of time.
Taxonomy and phylogeny of the Rove beetle genus Phlaeopterus (Coleoptera: staphylinidae: Omaliinae: anthophagini)The rove beetle genus Phlaeopterus contained 15 species prior to this work, which are found in mountainous regions of northwestern North America, and in East Siberia for one species. These beetles can be found in perpetually cold, wet habitats, usually living in close association with permanent or long-lasting alpine snowfields. Very little is known of the life history of Phlaeopterus, but they have been observed on the surface of snowfields mating as well as feeding on windblown arthropods that have become stranded on snowfield's surface. In this thesis, I present a taxonomic revision of the genus Phlaeopterus as well as a phylogeny using Bayesian and maximum likelihood methods with 46 morphological characters and the mitochondrial gene COI. I found discordance between the morphological and molecular phylogenies, as well as between maximum likelihood and Bayesian methods. Phlaeopterus castaneus and Phlaeopterus loganensis, species with distinct morphology but identical COI sequence data, appear to have undergone recent hybridization in the Rocky Mountains where their ranges overlap. I found strong support for the synonymy of the monotypic genus Vellica with Phlaeopterus. Published taxonomic hypotheses were mostly supported and a priori hypotheses received mixed support. Additionally, the genus Phlaeopterus is re-described, a dichotomous key of all species is provided, and eight new species are described. Two of these, Phlaeopterus bakerensis n. sp., and Phlaeopterus olympicus n. sp., are highly endemic snowfield-associated species, and have not been collected since the late 1970s and early 1980s respectively, lending concern to their conservation status.