Roads are one of the most recognizable artifacts of human habitation and development. They cross various landscapes and expand with the increasing density of human settlements. While these structures are vital in facilitating vehicular transportation, they can also have unintended negative consequences for natural ecosystems, such as road-related wildlife mortality. To examine the negative impacts of roads on wildlife at a local level, I quantified the frequency and patterns of road mortality across a yearlong study period in a study area within Montgomery and Giles Counties in southwest Virginia. I also examined relationships between roadkill patterns and several land and road variables, hoping to close a current literature gap by focusing specifically on small and meso-mammals weighing less than 15kg. I recorded the location and species of carcasses found along predetermined routes, including roads with variable speed limits, road infrastructure, and adjacent land cover. I used government-provided data sets, satellite imagery, and field verification to characterize our study routes. I recorded 294 carcasses and identified 221, of which 84% were small or meso-mammals, including 11 taxa. The most frequent roadkill taxa were tree squirrels (Sciurus sp.), opossums (Didelphis virginiana), striped skunks (Mephitus mephitis), and raccoons (Procyon lotor). I found three roadkill hotspots, all along a major highway, and a high frequency of roadkill in spring, autumn, and early winter. High posted speed limits, the presence of artificial road lighting, and high proportions of forest and early successional growth cover (often present in pastures) were associated with an increased frequency of wildlife-vehicle collisions. / Roads are one of the most recognizable artifacts of human habitation and development. They cross various landscapes and expand with the increasing density of human settlements. While these structures are vital in facilitating automobile transportation, they can also have unintended negative consequences for natural ecosystems, such as roadkill. To examine the negative impacts of roads on local wildlife, I studied the frequency, patterns, and causes of road mortality across a year-long study period. I also examined relationships between frequent roadkill hotspots and several land and road variables in a Montgomery and Giles Counties study area in southwest Virginia. My project focused on small and medium-sized mammals because they are rarely considered in other roadkill studies. I collected field data on the location and species of carcasses observed on surveys along predetermined routes, including roads with variable speed limits, road infrastructure, and adjacent land cover. I used government-provided data sets, imagery, and field verification to characterize study routes. I recorded 294 carcasses and identified 221, 84% of which were small and medium-sized mammals. Roadkill frequency was highest in spring, autumn, and late winter. I found that high posted speed limits, the presence of artificial lighting, high forest cover, and high early successional growth cover (such as shrubbery and small trees in pastures) were associated with a higher frequency of wildlife-vehicle collisions.

No description available.

Understanding the history of diversification in the North American deserts has long been a goal of biogeographers and evolutionary biologists. While it seems that a consensus is forming regarding the patterns of diversification in the Nearctic deserts in vertebrate taxa, little work has been done exploring the historical biogeography of widespread invertebrate taxa. Before a robust model of geobiotic change in the North American deserts can be proposed, it needs to be determined if the same historical events affected vertebrate and invertebrate taxa in the same way. I explored the phylogeographic patterns in four groups of widespread nocturnal velvet ants using two rDNA loci, the internal transcribed spacer regions 1 and 2 (ITS1 and ITS2). I used Bayesian phylogenetic analyses and haplotype network analyses to determine if a consistent geographic pattern exists among species and populations within each group. I also used molecular dating techniques to estimate divergence dates for each of the major phylogenetic clades. These analyses indicate that the species-level divergences in some groups occurred in the Neogene, and likely were driven by mountain building during Miocene-Pliocene times (~5 Ma) similar to the divergences in many vertebrate taxa, while species-level divergence in other groups occurred during the Pleistocene (1.8-0.1 Ma) and were likely driven by climatic oscillations and range contractions and expansion. Several recent studies have suggested that Neogene mountain-building events were more important to the development of a diverse desert-adapted biota. My research suggests, however, that both Neogene events and Pleistocene climatic changes were influential in the development of a species-rich nocturnal velvet ant fauna.

No description available.

Doctor of Philosophy / Department of Entomology / Gregory Zolnerowich / The subfamily Tillinae is composed of approximately 700 species with a cosmopolitan distribution. In the New World, the group is composed of 164 species classified in 12 genera. Tillinids are generalist predators of other insects but there is some ecological specificity among related species (i.e. predation on bark and wood-boring beetles). The systematics and biogeography of the subfamily have never been studied. Several genera inhabiting the New World have never been revised, a number of species in the group were described more than 50 years ago, and many of those descriptions were inadequate. Consequently, I present here the first systematic and biogeographic study of the Tillinae in the New World. First, a revision of the New World Tillinae, excluding the species-rich Cymatodera Gray is presented. The diagnosis and redescription of 26 species from 11 of the 12 tillinid genera from the New World are given; a new synonym, keys to genera and species, and distribution maps for all the genera treated here are also given. Collection data for all species examined is presented. A new genus was described based on this work in a separate publication. Second, a phylogenetic analysis based on 91 morphological characters and a molecular phylogenetic study based on the analysis of three loci, 16S rDNA, COI and 28S rDNA, for 89 taxa in 37 genera is presented. Results were compared with previous classifications at the subfamily level. Results are generally consistent, recovering Tillinae as a derived and monophyletic group; Old World tillinids were found to be basal groups and sister to New World Tillinae; the New World genus Onychotillus was found to be sister to remaining New World Tillinae; the small genera Barrotillus, Callotillus, Monophylla and Neocallotillus were recovered as basal lineages within the New World Tillinae with intergeneric relations not fully resolved; and the species-rich Cymatodera was found to be a paraphyletic group by the inclusion of the genera Araeodontia, Bogcia, Cymatoderella and Lecontella. A phylogeny was also constructed based on a concatenated molecular + morphology dataset; the topology obtained from this analysis is generally consistent with the molecular- and morphology-based phylogenies, separately. Finally, a hypothesis of the historical biogeography of Cymatodera, the most species-rich genus in the subfamily Tillinae, is presented. The genus is endemic to, but broadly distributed, in the New World. The principal aim of the study was to infer the age of origin of the group. Hypotheses regarding the center of origin, patterns of distribution, and putative processes that led to the widespread distribution of this group are presented. A phylogenetic analysis of 50 New World tillinid species was constructed using the markers 16S rDNA, COI, and 28S rDNA. A relaxed molecular clock calibrated with three secondary dates derived from other time-calibrated phylogenies is presented. Biogeographic processes were studied using a Bayesian Binary Markov Chain Monte Carlo analysis in the software Reconstruct Ancestral State in Phylogenies. Results obtained here indicate that Cymatodera emerged approximately 71.5 MYA during the mid-Cretaceous in what is now southwestern USA and northern Mexico. Two major dispersal events occurred during the evolution of the Cymatodera lineage, the first, an eastern migration process, and the second, a southern migration event, the latter route had a greater impact on the diversification of the group. Overall, this research provides a solid foundation for studying the systematics and biogeography of the world Tillinae. Species with recent shared ancestry tend to have similar functional traits for exploiting similar resources. A robust phylogenetic analysis can help elucidate prey preferences or other biological traits for species whose biology is poorly known. This study will also serve as a foundation to investigate broader evolutionary aspects of the subfamily, such as predator-prey associations, mimicry, and the emergence and diversification of pheromone reception, one of the most interesting aspects within the evolutionary history of the group.

Evolutionary transitions between marine and freshwater habitats are rare events that can have profound impacts on aquatic biodiversity. The main goal of my thesis is determining the processes involved in transitions between marine and freshwater biomes, and the resulting patterns of diversity using phylogenetic approaches. To test hypotheses regarding the geography, timing, frequency, and mechanisms regulating biome transitions I generated multi-locus time-calibrated molecular phylogenies for groups of fishes that include both exclusively marine and freshwater species. My analysis of anchovies demonstrated that Neotropical freshwater anchovies represent a monophyletic radiation with a single origin in South American freshwaters. I used a phylogeny of herring and allies (Clupeiformes) to investigate the evolution of diadromy, a migratory behavior in which individuals move between oceans and freshwater habitats for reproduction and feeding. These analyses do not support the hypothesis that differences in productivity between marine and freshwater explain the origins of diadromous lineages. Diadromy has been considered an evolutionary pathway for permanent biome transitions, however I found that diadromy almost never produces a fully marine or freshwater clade. Marine lineages often invade continental freshwaters during episodes of marine incursion. In South America, the rich diversity of marine derived fish lineages invaded during Eocene marine incursions from either the Pacific or the Caribbean, and Oligocene marine incursions from the Caribbean. I falsified the highly cited Miocene marine incursion hypothesis, but found that the Pebas Mega-Wetland catalyzed diversification in some marine derived lineages. Using diversification analyses, I investigated the evolutionary processes that have generated disparate patterns of diversity between continents and oceans. I found that freshwater silversides have higher speciation and extinction rates than marine silversides. Lineages accumulation plots suggest ecological limits are not regulating clade growth in either marine or freshwater biomes. Overall, biome conservatism is a widespread pattern among fishes, and this pattern is largely driven by competition in clades that are physiologically capable of biome transitions. Biome transitions are facilitated by rare paleogeographic events, such as marine incursions. Finally, a difference in net diversification rate is the macroevolutionary mechanism that best explains the difference in diversity between continents and oceans.

The genus Fucus (Phaeophyceae) has nine commonly accepted species, six of which inhabit North American shores: F. gardneri, F. serratus, F. distichus, F. evanescens, F. vesiculosus, and F. spiralis. Fucus inhabit the intertidal zones of the Atlantic, Pacific and Arctic Oceans and due to their highly plastic and morphologically simple phenotypes, are valuable candidates for molecular phylogenetic research. Furthermore, Fucus species are valuable for biogeographic investigations due to their relatively slow migration, limited dispersal range, and easily collected distribution. The closest ancestral species to the genus is a Pacific endemic Hesperophycus californicus supporting a North Pacific origin of the species (Serrão et al. 1999). However, a closer relationship between Atlantic and Arctic Fucus has been described casting doubt on the Pacific origins of the genus (Lindstrom 2001, Dunton 1992). The investigation of Fucus across this area is necessary to elucidate the apparent contradiction in the origin of the genus. Samples were collected from 79 locations across North American waters. The amplification of the divergent mtDNA spacer region was performed to assess taxonomic placement of 55 collected species and reconstruct the biogeography of North American Fucus species. Morphological analysis was also completed based on 21 measured characteristics in an attempt to support molecular analysis. Results of the study indicate two distinct lineages among collected samples. One lineage (F. spiralis and F. vesiculosus) with a distinct Atlantic origin and the second lineage (F. distichus and F. serratus) with a widely distributed F. distichus, and the Atlantic F. serratus. Morphological analysis and statistical support for these lineages was determined through discriminant analysis of the collected samples. Overall results determined biogeographic influences in the F. distichus species complex across Arctic, Pacific, and Atlantic regions with little apparent biogeographical influence within F. vesiculosus, F. serratus and F. spiralis. Closer phylogenetic relationships between Arctic and Atlantic samples were apparent as suggested by Lindstrom (2001) and Dunton (1992).

The genus Fucus (Phaeophyceae) has nine commonly accepted species, six of which inhabit North American shores: F. gardneri, F. serratus, F. distichus, F. evanescens, F. vesiculosus, and F. spiralis. Fucus inhabit the intertidal zones of the Atlantic, Pacific and Arctic Oceans and due to their highly plastic and morphologically simple phenotypes, are valuable candidates for molecular phylogenetic research. Furthermore, Fucus species are valuable for biogeographic investigations due to their relatively slow migration, limited dispersal range, and easily collected distribution. The closest ancestral species to the genus is a Pacific endemic Hesperophycus californicus supporting a North Pacific origin of the species (Serrão et al. 1999). However, a closer relationship between Atlantic and Arctic Fucus has been described casting doubt on the Pacific origins of the genus (Lindstrom 2001, Dunton 1992). The investigation of Fucus across this area is necessary to elucidate the apparent contradiction in the origin of the genus. Samples were collected from 79 locations across North American waters. The amplification of the divergent mtDNA spacer region was performed to assess taxonomic placement of 55 collected species and reconstruct the biogeography of North American Fucus species. Morphological analysis was also completed based on 21 measured characteristics in an attempt to support molecular analysis. Results of the study indicate two distinct lineages among collected samples. One lineage (F. spiralis and F. vesiculosus) with a distinct Atlantic origin and the second lineage (F. distichus and F. serratus) with a widely distributed F. distichus, and the Atlantic F. serratus. Morphological analysis and statistical support for these lineages was determined through discriminant analysis of the collected samples. Overall results determined biogeographic influences in the F. distichus species complex across Arctic, Pacific, and Atlantic regions with little apparent biogeographical influence within F. vesiculosus, F. serratus and F. spiralis. Closer phylogenetic relationships between Arctic and Atlantic samples were apparent as suggested by Lindstrom (2001) and Dunton (1992).

Title from title page of PDF (University of Missouri--St. Louis, viewed February 10, 2010). Includes bibliographical references.

No description available.