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Articles 3841 - 3870 of 19754

Full-Text Articles in Ecology and Evolutionary Biology

Native And Non-Native Ant Impacts On Soil Microbes, Hannah A. Stewart May 2022

Native And Non-Native Ant Impacts On Soil Microbes, Hannah A. Stewart

Biology Theses

Organisms produce chemical weapons for defense, but target organisms can develop resistance. In their introduced range, non-native species may bring “novel weapons” against which native organisms have not co-evolved resistance. The invasive European fire ant (Myrmica rubra) may have brought antimicrobial secretions to the Northeastern United States that are novel weapons against native fungal and bacterial soil organisms. I hypothesized that M. rubra would better inhibit seed pathogens resulting in greater emergence of native myrmecochorous Viola sororia seeds and, as a side effect, more strongly inhibit arbuscular mycorrhizal fungi than a native seed dispersing ant (Aphaenogaster picea …

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An Overview Of The Current Research On Epiphyte Ecology, Kelsey Inman-Carter May 2022

An Overview Of The Current Research On Epiphyte Ecology, Kelsey Inman-Carter

Honors Projects

Epiphytes are non-parasitic, photosynthetic organisms that depend on other photosynthetic host organisms for support. Epiphytes can be found both in aquatic and terrestrial habitats. The interactions between epiphytes and their hosts can vary based on both their habitat and the features of individual hosts. This review explores the many facets of epiphyte research, including: the diversity of epiphytes in aquatic and terrestrial habitats; the effects of host-epiphyte interactions on the hosts; and the abiotic and biotic interactions that together determine epiphyte community composition.

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Nitrogen Availability In Dune Systems And Its Effect On Root Fungal Endophyte Communities., Haley E. Sage May 2022

Nitrogen Availability In Dune Systems And Its Effect On Root Fungal Endophyte Communities., Haley E. Sage

College of Arts & Sciences Senior Theses

As global change persists, changes in resource availability can influence plant-microbe interactions. To understand how resource availability can influence these interactions and species diversity, I focused this research on how varying nitrogen (N) levels affect root endophyte communities in the plant species Ammophila breviligulata, an ecosystem engineer in the dune system. I analyzed the relationship between nitrogen addition and microbial community composition across 60 plots treated with three nitrogen addition levels (control, low, and high) in a long-term experimental field site in the Lake Michigan dunes. I identified Ammophila breviligulata's root endophyte community after creating a culture collection and …

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Incorporating Human Effects In Quantifying Mechanisms Of Stream Fish Community Structure Using Metacommunity Theory, Lauren E. Stoczynski May 2022

Incorporating Human Effects In Quantifying Mechanisms Of Stream Fish Community Structure Using Metacommunity Theory, Lauren E. Stoczynski

All Dissertations

Metacommunity theory incorporates local and regional factors to understand how biotic communities are structured across the landscape. Despite established knowledge of how humans impact aquatic systems, inclusion of anthropogenic factors in metacommunity studies have been largely ignored. Additionally, alpha, beta, and gamma diversity can all be explored at the metacommunity level to investigate mechanistic drivers of community structure. Beta diversity can be further partitioned into turnover and richness difference components, each with different mechanistic drivers. Streams provide an excellent study system for metacommunity research because of the dendritic structure of watersheds and the natural delineation that watershed boundaries provide. Large-extent …

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Examining The Invasion Of Bush Honeysuckle Through A Phylogenetic Analysis, Phoebe Bruffett May 2022

Examining The Invasion Of Bush Honeysuckle Through A Phylogenetic Analysis, Phoebe Bruffett

Biological Sciences Undergraduate Honors Theses

The mechanisms underlying the continual spread of invasive plants within their respective non-native ranges is a major focal point to invasion research. Many theories have been proposed to understand these invasions, each with different implications for the predicted range for invasive plants. Lonicera maackii provides an exceptional opportunity to examine the effectiveness of these theories to explain the trends of invasive plants. Lonicera maackii is native to eastern Asia, but has invaded much of the eastern United States, presenting a severe threat to the health of forest and other natural areas. Recent analysis of the climatic envelopes uncovered a significant …

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Investigating The Potential Role For The Nervous System In Controlling Regeneration In Nematostella Vectensis, Kristen Malir May 2022

Investigating The Potential Role For The Nervous System In Controlling Regeneration In Nematostella Vectensis, Kristen Malir

Biological Sciences Undergraduate Honors Theses

Nematostella vectensis is a marine sea animal that has become a model for developmental and evolutionary research. Included in the phylum Cnidaria, N. vectensis’ was chosen as the model for this research. Not only can this animal go through asexual and sexual reproduction, but it also has the ability to regenerate. Although much research has been put forth in an effort to understand regeneration better, much is still unknown. The underlying mechanisms of regeneration in Cnidaria are illusive; however, studies within vertebrates have shown the substantial role of the nervous system. The objective of this experiment is to test if …

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The Synchronization Of Nocturnal Pollinator Behavior And Apple Flower Nectar Production, Madison Jennings May 2022

The Synchronization Of Nocturnal Pollinator Behavior And Apple Flower Nectar Production, Madison Jennings

Biological Sciences Undergraduate Honors Theses

Insects perform an essential ecological service by facilitating the pollination of crops for food production worldwide. Recent declines in diurnal bee populations threaten food security and has led to growing concerns about existent pollination methods. Pollination contributions by native nocturnal insects have been documented to occur in a variety of systems, thought to be supported by the plant’s attractant and reward system. If this is the case, pollination of flowers by nocturnal vectors may be influenced by circadian cycles of nectar production and insect activity. To test this hypothesis, we recorded insect abundance of nocturnal pollinators periodically throughout the night …

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Using Ai To Examine Nocturnal Moth Pollination, Conor Moriarty May 2022

Using Ai To Examine Nocturnal Moth Pollination, Conor Moriarty

Biological Sciences Undergraduate Honors Theses

The importance of insect-mediated agriculture cannot be understated especially in the wake of pollinator population declines. Most research of insect-mediated pollination is focused on diurnal pollinators like the honeybee (Apis mellifera). Deepening our understanding of how other pollinators, such as nocturnal pollinators, can benefit agriculture and ecosystems will be very important as honeybee populations decline. I explored nocturnal moth interactions with flowering apple flowers during their pollination season to better understand how these nocturnal pollinators interact with the plants. To accomplish this, I used a University of Arkansas farm area with a dedicated apple orchard. I gathered my raw data …

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Effects Of Vegetation Heterogeneity On Multiphasic Treatment Outcomes In Sagebrush Steppe, Rebecca Donaldson May 2022

Effects Of Vegetation Heterogeneity On Multiphasic Treatment Outcomes In Sagebrush Steppe, Rebecca Donaldson

Boise State University Theses and Dissertations

Exotic annual grass invasion into western North America has led to significant loss of native perennials, altering the structure and function of sagebrush-steppe ecosystems. Monitoring and assessment of necessary restoration treatments have provided mixed evidence of success. We hypothesized that treatment outcomes would be influenced by restoration strategy (e.g., the timing of herbicide or drill seeding) and by within-treatment vegetation heterogeneity. We evaluated exotic annual grass and exotic perennial forb response to three replicate treatments of the pre-emergent herbicides indaziflam and imazapic, and a combination treatment of both herbicides, followed with the broadleaf herbicide, aminopyralid, at a highly invaded site …

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Sex, Body Size, And Winter Weather Explain Migration Strategies In A Partial Migrant Population Of American Kestrels (Falco Sparverius), Sadie Claire Ranck May 2022

Sex, Body Size, And Winter Weather Explain Migration Strategies In A Partial Migrant Population Of American Kestrels (Falco Sparverius), Sadie Claire Ranck

Boise State University Theses and Dissertations

Partially migratory systems describe populations that consist of both individuals that migrate away from the breeding grounds for the winter, and others that remain resident near their nesting sites year-round. Partial migration is the most common type of migration across all animal taxa, but the evolution, maintenance, and consequences associated with different movement strategies are still poorly understood. Studying the factors that drive migratory strategies and the associated consequences of those decisions is important to understand how migratory animals may adapt to climate change. Partial migrant populations offer a great opportunity for which to study these questions because individuals with …

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The Effects Of Roads On Movement, Flight Dynamics, Occupancy, And Productivity In Barn Owls (Tyto Alba), Brian Thomas Busby May 2022

The Effects Of Roads On Movement, Flight Dynamics, Occupancy, And Productivity In Barn Owls (Tyto Alba), Brian Thomas Busby

Boise State University Theses and Dissertations

Barn Owls (Tyto alba) are a species of conservation concern in many portions of their cosmopolitan range. One important factor contributing to population declines and sometimes local extirpations is roads, which can cause direct mortality through Barn Owl-vehicle collisions, fragment habitat, limit dispersal and movement, and imperil long-term population viability. However, the effects of roads on Barn Owl reproduction are less clear. Further, the cumulative effects of roads on Barn Owls can be dependent on how they respond to them. Road and traffic responses of animals have been classified into four categories: 1) speeders, who increase speed to …

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Severe Hypoxia Up-Regulates Gluconeogenesis In Daphnia, Morad C. Malek May 2022

Severe Hypoxia Up-Regulates Gluconeogenesis In Daphnia, Morad C. Malek

Undergraduate Honors Theses

Hypoxia is a significant low oxygen state that has complex and diverse impacts on organisms. In aerobes, various adaptive responses to hypoxia are observed that vary depending on the level of oxygen depletion and previous adaptation, hence the continued attention to hypoxia as an important abiotic stressor. Adaptive responses to hypoxia are primarily governed by the hypoxia-inducible factors (HIFs), which activate downstream genetic pathways responsible for oxygen transport and metabolic plasticity. In aquatic habitats, oxygen availability can vary greatly over time and space. Therefore, aquatic organisms’ adaptation to hypoxia is likely pervasive, especially in genotypes originating from waterbodies prone to …

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The Effects Of Dissolved And Suspended Solids On Freshwater Meiofauna, Jessica Cline May 2022

The Effects Of Dissolved And Suspended Solids On Freshwater Meiofauna, Jessica Cline

Honors Theses

Meiofauna include small-sized animals (< 1mm) distributed in all aquatic ecosystems on Earth, where they play fundamental trophic and ecological roles. The biodiversity of marine meiofauna and its links with anthropogenic activities is routinely investigated, however, freshwater communities are less known. This is particularly true for the Southeastern United States, which is greatly investigated and elected a hotspot of biodiversity for larger species but very little is known about the meiofauna. The purpose of this research is to reveal the biodiversity of meiofauna from the Tennessee River and test for potential correlations with anthropogenic activities. As a proxy for pollution, dissolved and suspended solids were considered in this study. The research hypothesis is that meiofaunal biodiversity would be affected by possible changes of dissolved and suspended solids in the water column. Possible mechanisms causing biodiversity shifts could be ascribed to osmotic stresses of animals to cope with variation in dissolved solids or, more indirectly, because different sunlight penetration caused by suspended solids would affect primary production. To test the hypothesis, water samples were collected from nine stations located along the Tennessee River in Hamilton County. Each station was visited three times, and, during each visit, environmental parameters (including dissolved and suspended solids) were measured. Meiofauna biodiversity (estimated as richness, community composition, and phylogenetic diversity) was revealed using a metagenomic approach. Statistical analyses were applied to test for possible correlations between the biodiversity estimates and the measured environmental parameters. Results show a high biodiversity of meiofauna with more than 200 amplicon-sequence variants distributed across 10 metazoan phyla. Environmental conditions are highly variable among stations and statistical analyses show that while both dissolved solids (TDS) and turbidity (suspended solids, NTU) did not significantly affect meiofauna biodiversity in the collected samples, various other water, and sediment metrics were found to be significant predictors of meiofauna biodiversity. In conclusion, the results of this project not only reveal for the first time the meiofauna biodiversity from the Tennessee River, but also suggest that meiofauna could be used as bioindicators for several anthropogenic activities in freshwater ecosystems.

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Fish Community Assembly At Multiple Spatial Scales In East Texas Streams, Jake R. Swanson May 2022

Fish Community Assembly At Multiple Spatial Scales In East Texas Streams, Jake R. Swanson

Electronic Theses and Dissertations

Stream communities are structured by environmental processes that vary in strength across different spatiotemporal scales. Therefore, revealing how stream fish communities are influenced by environmental gradients may clarify how communities respond to disturbance associated with anthropogenic change. I investigated the relative role environmental variables play in the processes that structure the taxonomic and functional diversity of stream fish communities, as well as historical trends in occurrence and local habitat associated with a species of greatest conservation need within east Texas. The results of this study indicate that stream sites with more habitat complexity and stability support a more taxonomically and …

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Relative Palatability And Efficacy Of Brodifacoum-25d Conservation Rodenticide Pellets For Mouse Eradication On Midway Atoll, Peter J. Kappes, Shane R. Siers, Israel L. Leinbach, Robert T. Sugihara, Wesley J. Jolley, Jonathan H. Plissner, Elizabeth N. Flint, Kelly L. Goodale, Gregg R. Howald May 2022

Relative Palatability And Efficacy Of Brodifacoum-25d Conservation Rodenticide Pellets For Mouse Eradication On Midway Atoll, Peter J. Kappes, Shane R. Siers, Israel L. Leinbach, Robert T. Sugihara, Wesley J. Jolley, Jonathan H. Plissner, Elizabeth N. Flint, Kelly L. Goodale, Gregg R. Howald

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive mice (Mus spp.) can negatively impact island species and ecosystems. Because fewer island rodent eradications have been attempted for mice compared to rats (Rattus spp.), less is known about efficacy and palatability of rodenticide baits for mouse eradications. We performed a series of bait acceptance and efficacy cage trials using a standard formulation of brodifacoum-based rodenticide on wild-caught mice from Sand Island, Midway Atoll, to help inform a proposed eradication there. Mice were offered ad libitum brodifacoum pellets along with various alternative food sources, and a “no choice” treatment group received only bait pellets. Mortality in the no choice …

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Effect Of Larval Experience On Learning Mate Preference In Bicyclus Anynana, Taryn Tibbs May 2022

Effect Of Larval Experience On Learning Mate Preference In Bicyclus Anynana, Taryn Tibbs

Biological Sciences Undergraduate Honors Theses

Phenotypic traits are shaped by the interaction of an organism's genes and the environment they experience. The plasticity of phenotypic traits is particularly responsive to developmental environments which can shape adult traits, such as expressed behaviors like mate choice and the ability to learn preferences. The Lepidoptera species Bicyclus anynana has been shown to learn mate preference based on social interaction following emergence from the chrysalis, however if and how the social complexity of the larval experience affects this ability to learn is less understood. Here I test the effects of isolation during the larval period on a female’s ability …

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The Influence Of Temperature And Body Size On Food Consumption In Prairie Lizards (Sceloporus Consobrinus), Morgan Pelley May 2022

The Influence Of Temperature And Body Size On Food Consumption In Prairie Lizards (Sceloporus Consobrinus), Morgan Pelley

Biological Sciences Undergraduate Honors Theses

Understanding the effect of temperature on physiological and digestive processes, such as voluntary consumption rate, is critical for assessing the impact of climate change. Food consumption is required for lizard survival and reproduction and its rate is dependent on temperature. For ectotherms, as temperatures increase, the amount of food consumed to meet the energy requirements related to survival and reproduction must also increase. Information on the amount of food voluntarily consumed may aid in determining if lizards can meet energy requirements. Such information could also aid in predicting survival of lizard populations, through construction of predictive climate change models. In …

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Risk-Prone And Risk-Averse Foraging Strategies Enable Niche Partitioning By Two Diurnal Orb-Weaving Spider Species, Mitchell D. Long May 2022

Risk-Prone And Risk-Averse Foraging Strategies Enable Niche Partitioning By Two Diurnal Orb-Weaving Spider Species, Mitchell D. Long

Electronic Theses and Dissertations

Niche partitioning is a major component in understanding community ecology and how ecologically similar species coexist. Temporal and spatial partitioning and differences in foraging strategy, including sensitivity to risk (variance), likely contribute to partitioning as well. Here, we approach this partitioning with fine resolution to investigate differences in overall strategy between two species of diurnal, orb-weaving spiders, Verrucosa arenata and Micrathena gracilis (Araneae: Araneidae), that share similar spatial positioning, temporal foraging window, and prey. Through field observation, we found that V. arenata individuals appear to increase spatial and temporal sampling to compensate for an overall risk-prone strategy that depends on …

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Habitat Preference Of F. Notatus And F. Olivaceus From A Reversed Hybrid Zone, Elizabeth Hart Williams May 2022

Habitat Preference Of F. Notatus And F. Olivaceus From A Reversed Hybrid Zone, Elizabeth Hart Williams

Honors Theses

Understanding the mechanisms driving habitat preference throughout an organism’s life opens doors to the further understanding of the origins of diversity. Two species of minnow, Fundulus notatus and Fundulus olivaceus, are ideal for ecological research on habitat preference. Ordinarily, F. notatus and F. olivaceus display habitat preferences of downstream and upstream, respectively, with minimal coexistence at confluences. However, in some drainages, these preferences are flipped, like those in the Tombigbee River basin. Members of both species were collected from the Tombigbee River, tagged with species and sex specific colored elastomer marks, and placed in either a homogeneous control or …

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Study Of Adaptive Radiation Effects On Sprint Performance In Anolis Ecomorphs, Alexander J. Bergeson May 2022

Study Of Adaptive Radiation Effects On Sprint Performance In Anolis Ecomorphs, Alexander J. Bergeson

Honors Thesis

Anolis lizards have become model organisms for the study of adaptive radiation and convergent evolution due to repeated patterns of specialization that allow them to live in different environmental niches within the habitats they occur. As part of a suite of adaptations for living in specific habitats, many species have repeatedly evolved specific changes in anatomy and physiology that make them better able to perform and survive in their surroundings. These specialized forms are referred to as “ecomorphs” based on their preferred habitats and have been well documented among Caribbean anoles. Mainland species, on the other hand, are less studied. …

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Site Fidelity Of Bottlenose Dolphins (Tursiops Truncatus) Using Elemental Analyses And Photo-Identification, Lauren R. Clance May 2022

Site Fidelity Of Bottlenose Dolphins (Tursiops Truncatus) Using Elemental Analyses And Photo-Identification, Lauren R. Clance

Graduate Theses and Dissertations (2019 - present)

The objective of this study was to determine if bottlenose dolphins (Tursiops truncatus) in Alabama waters acquire location-specific elemental signatures indicative of site fidelity. I measured trace metal concentrations (Chapter II) and stable isotope ratios (Chapter III) in skin from free-ranging dolphins remotely biopsied in Mobile Bay, the northern Gulf of Mexico (Gulf) and eastern Mississippi Sound (EMSS). Elemental findings were corroborated with photo-identification data. I found that dolphins acquired some location-specific elements indicative of site fidelity, with the greatest differences at geographic extremes, particularly relative to salinity. For trace metals, highest concentrations were found in winter, consistent with higher …

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Alfred Russel Wallace Notes 21: Wallace & The Doorway To The Universe, Charles H. Smith May 2022

Alfred Russel Wallace Notes 21: Wallace & The Doorway To The Universe, Charles H. Smith

Faculty/Staff Personal Papers

An important yet largely unrecognized theme in the thought of Alfred Russel Wallace (1823−1913) was his insistence that all dependably-reported phenomena, even those of aberrant nature, were worthy of a respectful kind of attention: that is, a kind which did not automatically banish difficult subjects to the realm of myth or superstition. In this work, Wallace’s philosophy in this direction is documented, and linked to the world of post-Age-of-Enlightenment revisionism.

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Epidemiology And Impacts Of A Leaf Spot Disease In Veratrum Viride (Melanthiaceae), Leeah R. Sutton, Foster Levy May 2022

Epidemiology And Impacts Of A Leaf Spot Disease In Veratrum Viride (Melanthiaceae), Leeah R. Sutton, Foster Levy

Undergraduate Honors Theses

Fungal phytopathogens can cause disease epidemics in crops, weeds, and
populations of native plants. To investigate the impact of a foliar phytopathogen on the native herbaceous species, Veratrum viride, a demographic and disease assessment was carried out on two high elevation grassy bald populations on Roan Mountain, Tennessee. A leaf spot disease impacted all plants in both populations, causing widespread premature senescence of leaves and stems. Disease severity increased over the course of the growing season. Based on host disease symptoms and fungal conidia morphology, Pseudocercosporella sublineolata was shown to be the causal pathogen. A study of herbarium specimens …

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Understanding The Role Of Small Mammals In Arctic Biogeochemical Cycling, Austin Roy May 2022

Understanding The Role Of Small Mammals In Arctic Biogeochemical Cycling, Austin Roy

Open Access Theses & Dissertations

Small mammals play an integral role in their ecosystems. This is especially true in northern ecosystems, where small mammals represent both top-down and bottom-up forces and can have strong effects on ecosystem function through affecting biogeochemical cycling. Despite these important effects, the role of small mammals in influencing biogeochemical cycling has been largely underappreciated in the understanding of arctic ecosystems, leading to a call to better understand how small mammal herbivores impact ecosystem processes including carbon cycling. The overarching goal of this dissertation is to assess how biogeochemical cycling is affected by small mammal herbivore presence, behavior, and population dynamics …

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Carnivoran Frugivory And Its Effect On Seed Dispersal, Plant Community Composition, Migration, And Biotic Carbon Storage, John P. Draper May 2022

Carnivoran Frugivory And Its Effect On Seed Dispersal, Plant Community Composition, Migration, And Biotic Carbon Storage, John P. Draper

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Seed dispersal by animals is important for the ecology of plants. It is particularly important to understand which animals are involved and how they move seeds differently from one another. Some seed dispersers are understudied despite ample evidence they consume fruits and seeds. This includes animals commonly referred to as carnivores in the order Carnivora. The overall goal of my dissertation was to describe the extent and quality of seed dispersal by Carnivorans, estimate important aspects of seed dispersal for a specific Carnivoran, the coyote, and estimate how differences between a coyote and songbirds affect where plants …

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Quantifying The Indirect Effect Of Wolves On Aspen In Northern Yellowstone National Park: Evidence For A Trophic Cascade?, Elaine M. Brice May 2022

Quantifying The Indirect Effect Of Wolves On Aspen In Northern Yellowstone National Park: Evidence For A Trophic Cascade?, Elaine M. Brice

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Yellowstone National Park is renowned for its incredible wildlife, and perhaps the most famous of these species is the gray wolf, which was reintroduced to the Park in the mid-1990s. After reintroduction, it was highly publicized by scientists, journalists, and environmentalists that the wolf both decreased elk density and changed elk behavior in a way that reduced elk effects on plants, a process known as a “trophic cascade.” Aspen, which is eaten by elk in winter, is one species at the forefront of Yellowstone trophic cascade research because it has been in decline across the Park for over a century. …

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Detecting Ecosystem Response To Restoration Efforts With Implications For Recovery Of The Threatened June Sucker (Chasmistes Liorus) In A Shallow, Eutrophic, Utah Lake, Ryan D. Dillingham May 2022

Detecting Ecosystem Response To Restoration Efforts With Implications For Recovery Of The Threatened June Sucker (Chasmistes Liorus) In A Shallow, Eutrophic, Utah Lake, Ryan D. Dillingham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Environmental damage associated with a growing human population will increase globally without active management. Restoration can promote ecosystem recovery, yet often fails to produce desired results and may require decades to achieve noticeable benefits. Detecting small, incremental change sis imperative in these difficult situations. Here, I demonstrate that restoration focused on fish removal triggers incremental responses in aquatic plants and animals. Removing common carp is expected to encourage recovery of aquatic plants, increasing animal habitat, resulting in more macroinvertebrates (e.g., aquatic insects, snails). Carp removal should also increase water clarity, improving visibility for fishes, thus increasing their ability to find …

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Spatiotemporal Factors Affecting The Occupancy And Phenology Of A Declining Songbird (Bachman's Sparrow - Peucaea Aestivalis) At The Western Extent Of Its Range, Liam G. Wolff May 2022

Spatiotemporal Factors Affecting The Occupancy And Phenology Of A Declining Songbird (Bachman's Sparrow - Peucaea Aestivalis) At The Western Extent Of Its Range, Liam G. Wolff

Electronic Theses and Dissertations

The Bachman’s Sparrow (Peucaea aestivalis) is a declining songbird that occurs throughout the southeastern United States. Bachman’s Sparrow is a Species of Greatest Conservation Need in Texas, but information crucial to management efforts, such as factors affecting their detectability and occupancy, is lacking. I investigated the predictors of Bachman’s Sparrow occupancy and phenology in Texas using detections from autonomous recording units coupled with site characteristics and weather data. My results indicate that Bachman’s Sparrow occupancy is associated with increasing herbaceous ground cover and decreasing basal area, distance to the nearest source population, and basal area when canopy height …

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Reconstructing Bison And Mammoth Migration During The Late Pleistocene And Early Holocene Of Central Texas Using Strontium Isotopes, Joshua John Porter May 2022

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 …

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Impact Of Genetic Variation And Timescale On Diatom Salinity Stress Response, Kala M. Downey May 2022

Impact Of Genetic Variation And Timescale On Diatom Salinity Stress Response, Kala M. Downey

Graduate Theses and Dissertations

Natural environments are dynamic, and organisms must sense and respond to changing conditions. One common way organisms deal with stressful environments is through gene expression changes, allowing for stress acclimation and resistance which occurs over varying time spans in different species. The recent evolutionary history of populations could greatly influence their ability to respond successfully. An evolutionary history in disturbed or fluctuating conditions could promote increased resistance or a more rapid response to these environmental stressors. To understand the impact of genotypic variation and timescales on response and acclimation to salinity changes, we have been exploiting the abilities of euryhaline …

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