Integrative Biology Commons^™

Exploring The Interrelationships Among Structural Complexity, Multi-Trophic Biodiversity, And Ecosystem Productivity In Forested Ecosystems., Ayanna St. Rose

Graduate Theses and Dissertations

Forests play a pivotal role in sustaining global biodiversity and mitigating the global climate, as they serve as the primary refuge for terrestrial biodiversity and effectively capture and store atmospheric carbon dioxide. However, changing climate and land use are altering the geographic distribution, physical structure, and productivity of forested ecosystems that can have profound impacts on biodiversity conservation, forest productivity, and global climate. This dissertation contributes to our understanding of multifaceted interactions between the physical and biological structural complexity and ecosystem functions in forested landscapes across the United states by using openly available data from two national networks: the National …

Human-Bat Interactions In A Disease Emergence Hotspot: Implications For Human Health And Bat Conservation, Reilly Tempest Jackson

Graduate Theses and Dissertations

Bats are an ecologically important taxon that can host zoonotic pathogens. Globally, many bat species are synanthropic and live closely with humans, often roosting in man-made structures. The spatial overlap between humans and bats creates opportunities for human-bat contact, which can lead to human exposure to bat-borne pathogens and conflicts that cause bat mortality. Despite this risk, little is known about the drivers and characteristics of these human-bat interactions in buildings and work is needed to understand this aspect of the wildlife-urban interface. In Chapter I, I present a literature review that identifies the geographic and taxonomic trends in reported …

Effects Of Seasonal Environment On Abundance, Behavior, Visual Signaling, And Perception In Prairie Butterflies, Grace Elizabeth Hirzel

Graduate Theses and Dissertations

Phenotypic plasticity is a widespread mechanism that allows animals to respond quickly to seasonal changes in their environment. However, the depth and complexity of these plastic responses is still being discovered. One aspect of seasonal physiology that is relatively unstudied is changes to sensory physiology and how it may explain changes in behavior. To determine how changes in seasonal conditions affect behavior, coloration, and vision, I examined populations of wild butterflies in Northwest Arkansas. Focusing on a single species, the common buckeye Junonia coenia, I found that seasonal coloration covaries with thermoregulating behavior and is accompanied by changes in visual …

Patterns Of Evolutionary Conservation And Divergence In The Short-Term Hyposalinity Stress Response Of A Euryhaline Diatom, Skeletonema Marinoi, Kathryn Judy

Graduate Theses and Dissertations

Survival under fluctuating environmental conditions, such as those increasing in frequency and magnitude under environmental change, requires a successful response to stress. Interspecific differences in stress responses may result in differential survival of species, even within a lineage. Diatoms may constitute one such lineage, as salinity tolerance among extant species is diverse, and the observation of frequent historic habitat transitions between marine and freshwater environments indicates that diatoms successfully mitigated (low) salinity stress in the past, followed by adaptation and diversification over evolutionary time scales. To understand to what extent the diatom hypoosmotic stress response consists of conserved and variable …

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 …

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 …

The Effects Of Multiple Stressors On Stream Communities: The Convergence Of Drought, Nutrient Pollution, And Invasive Species, Robert Joseph Fournier Iii

Graduate Theses and Dissertations

Freshwater systems experience multi-faceted degradation from a variety of ecological and environmental stressors. Three common stressors in these systems, drought, nutrient pollution, and invasive species, have wide-ranging effects on stream population- community- and ecosystem dynamics. We have a broad understanding of how each of these stressors works to influence stream systems independently. However, we still know relatively little about if, and how, these stressors might interact when they co-occur. Though drought is a natural part of many stream systems, all three of these stressors can be exacerbated or facilitated by anthropogenic actions. Accordingly, as human population and resource use continue …

Genetic Relationships Using Mitochondrial Versus Nuclear Markers: Is The Catfish Rag1 Gene Suitable For Species Differentiation In The Family Pangasiidae?, Huong Thanh Hoang

Graduate Theses and Dissertations

The Mekong River located in Southeast Asia is a global “hotspot” for aquatic biodiversity. It includes an extensive variety of fish species second only to the Amazon River in South America. Recent studies have revealed the impacts of anthropogenic and climate factors on this river system. Such impacts can result in the formation of barriers, which divide a species population and impede gene flow between separated sub-populations. Barriers influence evolutionary trajectories resulting in the generation of geographic variants or subspecies from an ancestral population. Catfish (Teleostei: Siluriformes) are a key species of the Mekong River ecosystem and are an essential …

The Functional Conservation Of Frazzled In Insects, Benjamin Wadsworth

Graduate Theses and Dissertations

Axons in the developing embryo receive and react to signals that direct their growth to reach target tissues at specified locations. The signal pathways that direct midline crossing of axons during embryonic development have been comprehensively examined in the past years using the Drosophila ventral nerve cord or the spinal cord as a model system. A number of these signaling mechanisms are conserved, however disparities have been found between species in general strategy or the molecular signals controlling the response of axons to guidance cues.

The Netrin-Frazzled pathway has been shown to aid in midline crossing of axons in the …