Physical Sciences and Mathematics Commons^™

Rodent Dental Microwear Texture Analysis As A Proxy For Fine-Scale Paleoenvironment Reconstruction, Jenny H. E. Burgman

Graduate Theses and Dissertations

Dental microwear texture analysis (DMTA) of fossil fauna has become a valuable tool for dietary inference and paleoenvironment reconstruction. Most of this work has utilized larger taxa with larger home ranges. These studies may result in broader-scale habitat inferences that could mask the details of complex mosaic habitats. Rodent DMTA offers an opportunity to work at finer spatial scales because most species have smaller home ranges. Rodents are also keystone species within their ecosystems, abundant, ubiquitous, and found in many fossil deposits. These attributes make them excellent proxies for environmental reconstructions. However, the application of DMTA to rodents remains relatively …

Reconstructing Bison And Mammoth Migration During The Late Pleistocene And Early Holocene Of Central Texas Using Strontium Isotopes, Joshua John Porter

Graduate Theses and Dissertations

During the Late Pleistocene (LP; past 130,000 years), over two-thirds of large mammal (>45kg) species went extinct globally. While the role of humans is hotly debated, the effect of these extinctions is growing clearer; the extinctions resulted in widespread and lasting faunal community reorganization. However, the impact of these extinctions on dietary and migratory behavior within faunal communities is unknown. Our study examines the impact of the megafaunal extinctions on the dietary and migratory behavior of surviving Bison individuals in Texas using carbon, oxygen, and strontium isotopes. Strontium isotopes are incorporated into mammalian enamel during their tooth development and …

The Hydrostatics And Hydrodynamics Of Prominent Heteromorph Ammonoid Morphotypes And The Functional Morphology Of Ammonitic Septa, David Joseph Peterman

Browse all Theses and Dissertations

Ammonoid cephalopods have chambered shells that regulated buoyancy. The morphology of their shells strongly influenced the physical properties acting on these animals during life. Heteromorph ammonoids, which undergo changes in coiling throughout ontogeny, are the focus of this dissertation. The biomechanics of these cephalopods are investigated in a framework involving functional morphology, paleoecology, and possible modes of life. Constructional constraints were investigated for the marginally-corrugated septal walls within the chambered ammonoid shell. These constraints governed the positive relationship between septal complexity and terminal size. Furthermore, increased septal complexity facilitated liquid retention via surface tension. More complex septa would have increased …

Post-Glacial Fire History Of Horsetail Fen And Human-Environment Interactions In The Teanaway Area Of The Eastern Cascades, Washington, Serafina Ferri

All Master's Theses

Landscapes of the Pacific Northwest have been shaped by dramatic shifts in climate since the last glacial maximum and more recently, by human activity. However, it is unclear how past relationships between people, fire, and climate interacted on the landscape. The purpose of this research was to reconstruct the post-glacial fire history of a wetland known as Horsetail Fen, located in the Teanaway area of the eastern Cascades of Washington State. The goal was to evaluate how fire activity has varied under different climatic scenarios during the last ~16,000 years and in relation to human land-use actions. This lake was …

Modern And Paleoecological Perspectives On A Terrestrial-Marine Linkage In The Falkland Islands, Dulcinea V. Groff

Electronic Theses and Dissertations

The Falkland Islands are a biodiversity hotspot in the South Atlantic Ocean, with some of the world’s most important populations of seabirds and seals. The impact of climate change on these marine populations and their coastal breeding habitat in the Falklands is unknown. Coastal grasslands of Poa flabellata (tussac grass) form critical breeding habitat for wildlife, but have been heavily degraded by the introduction of livestock in the 17^th century. This dissertation investigates the impacts of global change (climate change, grazing) on P. flabellata and its sensitivity to the fecal nutrient subsidies provided by marine wildlife. Chapter 1 provides …

Lessons From The Past: Unfolding The Dynamics Among Climate, Balkan Landscapes, And Humans Over The Past Millennium, Charuta J. Kulkarni

Dissertations, Theses, and Capstone Projects

The primary objective of this doctoral dissertation is to reconstruct the environmental history of the Central Balkans (Serbia) over the past millennium utilizing biological proxies (pollen, spores, and charcoal), geochemical signals through X-ray fluorescence (XRF), statistical analyses, and atomic mass spectrometry (AMS) ¹⁴C chronology. This dissertation establishes the first chronological framework for vegetation-landscape changes in Serbia and discusses the role of humans and climate as underlying processes.

Chapter 1 discusses the background and the nature of the research problem followed by the extensive literature review on the topic of the Holocene climate and paleoecology. The state of Holocene paleoecology …

Spatial Variation In Tooth Shape Of Miocene Populations Of Carcharocles Megalodon Across Ocean Basins, Maxwell John Bertsos

Browse all Theses and Dissertations

The extinct Lamniform species, Carcharocles megalodon, were some of the most geographically widespread apex predators in the fossil record. However, whether this cosmopolitan distribution was related to population level differences is unknown. The objective of this study is to assess whether variation in tooth morphology coincided with geographic dispersal. The underlying hypothesis is that variation in an aspect of functional morphology, such as tooth shape, suggests some level of population structuring. Detecting this relationship could potentially provide a mechanism that links population to functional relationships inherent in tooth morphology that may reflect period differences in ocean basins. This would offer …

Paleoecology Of Late Pleistocene Megaherbivores: Stable Isotope Reconstruction Of Environment, Climate, And Response, Aubrey Mae Bonde

UNLV Theses, Dissertations, Professional Papers, and Capstones

Late Pleistocene megaherbivore communities of the Pacific and Mountain West states of California and Nevada are under-analyzed in regard to ecological function (diet, mobility, niche partitioning, and range of ecological tolerance). Stable isotope analysis is a powerful tool that is known to recover primary paleodiet and paleoenvironmental information from biogenic materials, such as enamel and dentin. This dissertation explores the use of carbon and oxygen stable isotopes in Late Pleistocene (40-10 Ka) megaherbivore teeth to gain a better understanding of inter- and intra-specific behavior and reconstruct Late Pleistocene ecosystems of California and Nevada. Radiocarbon dates exist for most of the …

Sedimentological And Plant Taphonomic Evaluation Of The Early Middle Devonian Trout Valley Formation, Jonathan Allen

Honors Theses

The Trout Valley Formation of Emsian-Eifelian age, outcropped in Baxter State Park, Maine, consists offluvial and coastal deposits preserving early land plants. Massive, crudely bedded conglomerate represents deposits of proximal braided channels on an alluvial fan complex. Lithic sandstone bodies in channel-form geometries represent deposits of river channels draining the Acadian highlands whereas associated siltstones represent overbank deposits, intertidal flats, and tidal channels. Localized lenticular quartz arenites represent nearshore shelf bar deposits that were storm influenced. The majority of plant assemblages preserved mainly in siltstone lithologies are allochthonous and parautochthonous, with only one autochthonous assemblage identified in the sequence. Plant …