Life Sciences Commons^™

Linking Microbial Community Assembly In Flowers With Function Under Diverse Environmental Conditions: A Case Study Involving Erwinia Amylovora, Christopher Skylar Mcdaniel

All Graduate Theses and Dissertations, Fall 2023 to Present

Fire blight, a devastating disease of pome fruit trees caused by the bacterium Erwinia amylovora, can cause millions of dollars in losses for producers each year around the globe. Management approaches that involve use of antibiotics, such as streptomycin, can be effective; although concerns exist over pollinator and crop health when using them regularly. Recently, there have been developments that allow for biological agents such as microbes to curtail fire blight infection. These agents work by competing with Erwinia for resources or space, producing antibacterial compounds, or even killing Erwinia cells on contact. Unfortunately, these agents do not yet …

Using Biometrics, Behavioral Observations, And Multiple Molecular Techniques To Assess The Impacts Of Changes In Temperature And Salinity On The Common Bay Mussel (Mytilus Trossulus), Casey Martin

Dissertations and Theses

The intertidal zone is a place of rapid and frequent change that is home to a variety of creatures who are essential to the integrity of the habitat. Mussels are robust sessile bivalves that anchor to the rocks of the intertidal. The prominent species on the Oregon Coast, the Common Bay Mussel (Mytilus trossulus), plays an essential role as a coastal food source, water column filter, and barrier to prevent erosion due to wave action. Mytilus trossulus withstands daily shifts in temperature, salinity, and tide, as well as seasonal changes. Global climate change due to excess carbon emissions …

Illuminating The Drivers Of Genomic Diversification In Lamprologine Cichlids Of The Lower Congo River, Naoko P. Kurata

Dissertations, Theses, and Capstone Projects

Freshwater fishes are extraordinarily diverse, considering their available habitats represent a tiny proportion of the earth’s surface. Rivers connect heterogeneous habitats in a linear form and provide excellent simplified models to understand how aquatic biodiversity evolves. In particular, the lower Congo River (LCR) in west Central Africa consists of a dynamic hydroscape exhibiting extraordinary aquatic biodiversity, endemicity, and morphological and ecological specialization. This system is thus an excellent natural laboratory for understanding complex speciation and population diversification processes. In my research, I explore various drivers of diversification, and adaptive evolution in rheophilic lamprologine cichlids endemic to the LCR, including Lamprologus …

Understanding Context Dependent Responses To Climate Change In Arizona Tiger Salamanders (Ambystoma Mavortium Nebulosum), Kentrell Richardson

Masters Theses, 2020-current

Future emissions scenarios project climate change to increase average global temperatures by at least two ℃ in the next 50 years resulting in changes in local climate and causing increased variability within microclimates. Ectotherms are especially sensitive to climate change due to their dependence on environmental temperatures to regulate physiological functions. Changes in temperature are likely to impact thermally cued processes within amphibians and result in changes in variable magnitudes and directions within local populations.

Salamanders were placed in cups and partially submerged in a water bath and heated at a rate of ~0.27℃/ minute. Once salamanders were unable to …

The Effects Of Recent Climate Change On Spring Phenology, With A Special Focus On Patterns Of Bee Foraging, Michael Stemkovski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The date on which plants flower and on which bees begin to pollinate varies year-to-year depending on differences in weather. This seasonal timing is known as phenology, and it is already clear that climate change has pushed the spring phenology of many species earlier by increasing temperatures. This is particularly clear in flowering plants, but studying how and why the phenology of pollinators is shifting is more difficult. Most flowering plants rely on pollinators such as bees for their reproduction, and most bees rely on flowers for their sustenance, so bee and flower phenology has to overlap for the crucial …

Are Rising Seas Pushing Ghost Crabs Out Of Their Comfort Zone?, Finn Gillette

Honors Theses

Ghost crabs (Ocypode quadrata) can be found on sandy beaches bordering the western Atlantic Ocean. These semiterrestrial crustaceans are often found between the swash zone and the dunes on beaches. Dunes are critical refuges for ghost crabs during storms and extreme tide events. This makes them a useful indicator species for monitoring the effects of global warming-induced sea level rise on beach biota, as their distribution patterns among beach zones may correlate with shifts found in other species. Beach surveys conducted from 2015 onward assessed the population density of ghost crabs on beaches of Horry and Georgetown counties …

To Flee Or Not To Flee: How Range Dynamic Of Alpine Species Are Changing Through Time, Lian Noonan

WWU Graduate School Collection

In response to anthropogenic climate change, alpine floras in particular have been forecasted to shift their ranges upslope and north, yet recent analyses have shown otherwise. While a handful of floras have been found to track the trajectory of predictive models, most floristic elements have remained in their historical ranges despite a changing climate. Therefore, to improve the accuracy of models predicting range shifts, I address the following questions: (1) are mountain floras spatially structured through time; and (2) how are range dynamics of mountain floras changing through time. To address these questions, this study analyzed the herbarium records of …

Application Of Hierarchical Species Distribution Models To Avian Species Of South Dakota And The Upper Missouri River Basin, Reza Goljani Amirkhiz

Dissertations and Theses

Recognizing the distributional patterns of species can inform management actions and increase scientific knowledge about species. Habitat Suitability Models (HSMs) are valuable tools in modeling species’ niches and effects of climate change and anthropogenic and natural disturbances on species’ distributions and abundances. In this dissertation, I expanded the application of hierarchical HSMs for a rare bird (Virginia’s warbler) and an economically valuable bird (ring-necked pheasant) in South Dakota. Also, we developed multiscale HSMs for grassland birds in the Upper Missouri River Basin (UMRB) to quantify current habitat associations and predict the influences of climate and landcover change associated with the …

Exploring The Metabolic Capabilities And Biotransformation Potential Of Environmental Lactococcus Strains, Desirée Román Naranjo

Theses

The aim of this thesis is to characterize environmental Lactococcus strains to identify different and diverse metabolic capabilities that could be applied to microbial biotransformation, defined as the conversion of a cheap/waste substrate into a value-added product. Due to the increased amounts of food processing waste generated worldwide and the impact of climate change, new sustainable approaches are necessary to contribute to waste valorization and the circular bioeconomy. We ask to what extent and in what ways environment isolated Lactococcus strains could contribute to food biotransformation by metabolizing a different range of substrates. We do so to further understand and …

Quantifying Life History Energetics Of An Oviparous Elasmobranch Subject To Future Warming Water, Carolyn R. Wheeler

Graduate Doctoral Dissertations

Marine ectothermic fishes – fishes that do not regulate internal body temperature independent from the water temperature – are some of the most vulnerable organisms to rapid and alarming increases in environmental temperature occurring due to climate change mediated-ocean warming. For tropical fish species that live near their thermal maxima, this warming could be of grave consequence to individuals, populations, and whole marine ecosystems. Certain key life stages such as embryos and reproducing adults may be particularly vulnerable to warming given the excess energetic costs of these life stages, which may disallow compensation for extreme changes in temperature. One taxonomic …

Landscape Genomics Of The Tussock Cottongrass (Eriophorum Vaginatum) And The Dwarf Birch (Betula Nana) In North Central Alaska, Elizabeth Stunz

Open Access Theses & Dissertations

Global climate change has resulted in geographic range shifts of flora and fauna at a global scale. Extreme environments, like the Arctic, are seeing some of the most pronounced changes. This region covers 14% of the Earthâ??s land area, and while many arctic species are widespread, understanding ecotypic variation at the genomic level will be important for elucidating how range shifts will affect ecological processes. Increase in shrub cover is a major effect of ongoing climate change in arctic tundra ecosystems. The relative increases in abundance and cover of shrub species such as birch, willow, and alder (Betula, Salix, and …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

University of New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Chihuahuan Desert Rock Pool Community Assemblages: Patterns Of Taxonomic Diversity, Joseph Lee Mcdaniel

Open Access Theses & Dissertations

As climate change continues to become more prevalent, increasing temperatures and altering precipitation patterns will disrupt the environmental balance of ecosystems and spark the imminent threat of a 6th mass extinction event. Many researchers believe this has already begun, as losses for numerous taxonomic clades have been well documented; however, the loss of invertebrates is still unknown and may be much more severe than those of other animal clades. A significant factor contributing to the shortfall of invertebrate biodiversity loss is rooted in the lack of understanding of the diversity and distribution of these animals. There is still much to …

An Evaluation Of Landscape, Climate, And Management Impacts On Bumble Bees (Hymenoptera: Apidae: Bombus) In Agroecosystems, Morgan Elizabeth Christman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bumble bees play pivotal roles in pollinating wild and cultivated plant communities. Unfortunately, bumble bee populations are declining due to disturbances such as landscape conversion and climate change. Additionally, traps used to monitor pest insect populations often capture bumble bees, leading to a concern that trap captures increase bumble bee mortality. First, I studied bumble bee communities based on land cover and weather variables in agricultural fields in Utah. Bumble bee communities were more diverse in agricultural fields with more agricultural land in the surrounding area, low temperatures, and high humidity during the growing season, and less diverse in fields …

Connecting Above- And Belowground Effects Of Climate Warming On Bumble Bee Health, Francis Mullan

Master of Science in Integrative Biology Theses

Climate warming has been identified as one of the primary factors causing worldwide pollinator declines. One of the most at-risk groups of pollinators is bumble bees (Bombus spp.). Bumble bees are common, widespread, and key pollinators of a wide range of crops and wild plants. Although studies have examined the thermal physiological traits of individual bumble bees to understand how they may be impacted by climate warming, little to no studies have examined how climate warming may impact whole bumble bee colonies both in their ability to thermoregulate their nest for their brood or in their ability to forage …

Biodiversity And Global Change In Terrestrial Ecosystems, Timothy J. Ohlert

Biology ETDs

Terrestrial ecosystems are critical to human and ecological processes but many gaps in our knowledge remain regarding how terrestrial plant communities assemble and respond to global change. I used field experiments distributed around the world, including long-term experiments from the Sevilleta National Wildlife Refuge (SNWR) in New Mexico and deserts of the southwestern U.S., to evaluate the consequences of drought and other abiotic stressors on plant communities. Dominant grasses were particularly important for the productivity and structure of grasslands at SNWR. In general, the structure of desert plant communities had high resistance to extreme drought, though grasses and other perennial …

An Analysis Of The Effects Of Temperature And Other Environmental Factors On Microorganismal Productivity Within Aquatic Ecosystems Using Long-Term Data From Various Lter And Ilter Sites, Andrew Dorbu

Theses and Dissertations

Global climate change is a phenomenon resulting in more extreme weather patterns and species diversity loss. In this study, I explore the impacts of climate change on regional patterns of microbial productivity. Variation in microbial productivity was explained using temperature, salinity, and dissolved oxygen as predictors in regression models with data from the LTER and iLTER network of sites that ranged from the poles to the equator. I found a positive relationship between temperature and productivity. Antarctica and Arctic sites exhibited the strongest positive relationships supporting prior research demonstrating temperature as one of the driving forces of productivity change in …

The Potential Impact Of Climate Change On The Distributions Of Eleutherodactylus Cystignathoides And E. Planirostris (Anura: Eleutherodactylidae), Rebecca T. Chastain

Theses and Dissertations

Climate change is inducing changes in the distributions of many species, causing range shifts and habitat loss as well as facilitating invasions. It is a broad contributor to global amphibian decline, already causing mass extinctions and extirpations of amphibian populations, a phenomenon which is expected to continue. The understudied direct-developing frog Eleutherodactylus cystignathoides is a notable outlier, having rapidly expanded its distribution in recent years. This is of particular interest given that other eleutherodactylids, such as E. coqui and E. planirostris, have already shown propensity for rapid dispersal and invasion. Originally found in the southernmost tip of …

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 …

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 …

From Individuals To Communities: The Effect Of Climate Change On Ectothermic Predators, Matthew Lawrence Meehan

Electronic Thesis and Dissertation Repository

The living components of ecological systems exist within a nested hierarchy, consisting of individuals, populations, and communities. Because of this nestedness, climate change can greatly impact ecological systems, as whole-organism metabolic and physiological demands change for ectotherms under warming, the effects of which may compound with every succeeding level. Therefore, a multi-level approach can better isolate how climate change will reshape ecological systems. In my doctoral research, I used feeding and mesocosm experiments to examine how climate change affects ectothermic predators at the individual-, population-, and community-level, using mesostigmatic mites (Arachnida: Parasitiformes) as my model predator. My research objectives were …

Temperature-Dependent Developmental Plasticity In The Cardiorespiratory System Of Atlantic Salmon, Carlie A. Muir

Electronic Thesis and Dissertation Repository

Anthropogenic climate change is expected to have pervasive impacts on the performance and viability of fishes, as increasing temperatures create aerobically constrained environments for many species. Given the rapid rates of projected temperature increases, it is critical to evaluate the capacity for fish to respond to a changing thermal environment through phenotypic plasticity. In this thesis, I examined the capacity for developmental plasticity in the thermal performance of juvenile Atlantic salmon (Salmo salar) reared under two thermal regimes from fertilization, and investigated potential mechanistic underpinnings within the cardiorespiratory system. Cardiac performance was examined using a noninvasive Doppler echocardiograph …

A Tipping Point In The Ecuadorian Amazon Rainforest: Current And Future Land-Use And Climate Change Trends, Alula Shields

Masters Theses

Many regions of the Amazon are experiencing drastic changes as deforestation and climate change drive the world’s largest continuous rainforest towards a ‘tipping point’. These disturbances are changing natural cycles that once past a critical threshold, will mark an unstoppable transition to an altered ecosystem. Losing areas of the Amazon rainforest will have implications for the global climate, global carbon budget, and global hydrological regimes. Scholars have projected these tipping points for areas of the eastern Amazon rainforest, but much less scholarship focuses on the headwaters of the Western Amazon, an area of great cultural and biological importance. Ecuador is …

Impacts Of Changing Permafrost Conditions On Vegetation Productivity In The Northern Boreal Forest, Emily Ogden

Theses and Dissertations (Comprehensive)

Vegetation productivity across the boreal forest has increased over the past several decades. However, at a regional scale there is large variation from increased (greening) to decreased (browning) productivity and large areas with no measured change. Some of this variation can be explained by disturbances, such as wildfire, or by increased climate variability. In northern regions underlain by permafrost, the interactions between climate, disturbance, and vegetation productivity may be more complex. For my thesis, I used a time-series of ground thermal data from permafrost monitoring sites established by the Geological Survey of Canada along a latitudinal transect of the Northwest …

The Effects Of Average Annual Temperature On Flowering Times And Flower Count, Angela Copploe

Williams Honors College, Honors Research Projects

Over a course of 15 years, three different species of flowers were examined to see the relationship between the increase in average annual temperature, flowering time, and flower count.

An Elevational Gradient In Thermal Tolerance Among Daphnia From Western Maine Lakes, Wheeler Lowell

HON 499 Honors Thesis or Creative Project

With climate change threatening biodiversity worldwide, it is important to understand species’ physiological responses to changing thermal environments. This study examined whether thermal tolerance (measured as time to immobilization, Timm) in the zooplankton Daphnia catawba and D. schødleri varied along an elevational gradient in Western Maine. Specimens collected from five lakes were subjected to heat stress trials to look for inter-population variation. Thermal tolerance was strongly correlated with several elevation-driven lake temperature variables, with the percent of variation explained ranging from 13-37%. Daphnia from cooler, high-elevation lakes were more sensitive to elevated temperatures. While latitudinal gradients have been examined extensively, …

Three Lc-Ms Plant Metabolomics Studies Of Hop (Humulus) Species: Wild H. Neomexicanus, Drought Stress, And Agricultural Terroir, Taylan Morcol

Dissertations, Theses, and Capstone Projects

The hop plant (Humulus L., Cannabaceae) is a dioecious, perennial, twining vine with a long history of human use. Nowadays, hop plants are generally grown for their inflorescences (“cones”), which are used in brewing for their phytochemical metabolites. Many of these metabolites are involved in plant stress response and communication. Genetics and environment are two major factors that affect plant metabolism. In three separate metabolomics studies, this project examined the effects of both genetic and environmental factors on hop phytochemistry.

In the first study, 23 hop genotypes were grown in two different locations in the Pacific Northwest region of …

Investigating Local Adaptation To Hypoxia Stress In The Eastern Oyster Through Comparative Transcriptomics, Heather Nichole Smith

LSU Master's Theses

Climate change represents one of the most important challenges to biodiversity, therefore it is important to understand the mechanisms that allow species to respond to rapid environmental change. Here, we compared two populations of eastern oysters, Crassostrea virginica, from the Gulf of Mexico to study the mechanisms underlying hypoxia tolerance. Using a common garden experiment and comparative transcriptomics, we identified sets of genes involved in the hypoxia response and found differences in both the timing and baseline expression of hypoxia-responsive genes between tolerant and sensitive populations, consistent with a scenario of local adaptation. These genes include the signaling transcription factor …

Examining The Links Between Environmental Variation, Foraging Behaviour And Foraging Success In An Arctic Seabird, Alyssa Eby

Electronic Theses and Dissertations

Arctic regions are experiencing increasing variability in inter-annual sea ice dynamics ultimately impacting marine Arctic ecosystems. Arctic-breeding seabirds, such as thick-billed murres (Uria lomvia) are thus likely to be negatively impacted by fluctuating environmental conditions through its influence on prey availability. Additional extrinsic factors (colony size and chick demand) and intrinsic factors (sex) are also likely to impact foraging behaviour and success of murres in combination with environmental conditions. First, we tested the effect of colony size on colony sensitivity to environmental change at two low Arctic colonies of varying sizes, Coats Island, Nunavut and Digges Island, Nunavut …

Climate-Driven Impacts On Himalayan Aquatic Biodiversity: A Case Study Involving Snowtrout (Cyprinidae: Schizothorax), Riri Wiyanti Retnaningtyas

Graduate Theses and Dissertations

Monitoring biodiversity, to include its relative dispersal and contraction, has become a conservation task of great importance, particularly given the catastrophic and ongoing loss of habitat due to climate change. However, the timing, direction, and magnitude of these rates vary across taxa and ecosystems. Predicting specific impacts of climate change can thus be difficult and this, in turn, hampers management action. Metrics are needed to not only quantify contemporary requirements of species, but also predict potential distributions that fluctuate in lockstep with climate.

Montane ecosystems in the Himalayas are highly impacted by climate change, yet remain largely understudied due to …