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Theses and Dissertations

2023

Articles 1 - 15 of 15

Full-Text Articles in Ecology and Evolutionary Biology

Habitat Utilization Of Marsh And Adjacent Submerged Landscape By Fish And Macroinvertebrates In A Gulf Of Mexico Tidal Oligohaline Environment, Tia Offner Dec 2023

Habitat Utilization Of Marsh And Adjacent Submerged Landscape By Fish And Macroinvertebrates In A Gulf Of Mexico Tidal Oligohaline Environment, Tia Offner

Theses and Dissertations

Estuarine habitats are considered nursery habitats for fishes and invertebrates, but oligohaline environments are critically understudied. Using a seine net and fyke nets, we sampled Back Bay, Mississippi (USA), a low salinity estuary, once a month for a year to explore the temporal use of the marsh and adjacent submerged landscape by nekton species. We also looked at whether there is evidence of habitat preference in the most numerous nekton species. We used a novel habitat usage index (HUI) to compare seine and fyke net catches of our top 10 species, and evaluated catch size in relation to maturation size. …

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Towards Understanding The Interactions Between Ospreys And Human-Made Structures In The Tennessee River Valley, Natasha Karina Murphy Dec 2023

Towards Understanding The Interactions Between Ospreys And Human-Made Structures In The Tennessee River Valley, Natasha Karina Murphy

Theses and Dissertations

Raptor nests on human-built structures represent a significant source of conflict as they can result in bird mortality, fires, structure damage, service distribution, or power outages when falling nest materials or animals connect with energized conductors. Power companies, such as the Tennessee Valley Authority (TVA), wish to mitigate these conflicts to avoid service disruptions. In this dissertation, I present my work towards understanding and mitigating the interactions between Ospreys (Pandion haliaetus) and human-made structures. To achieve this, I explored multiple elements of conflict identification, monitoring, and basic ecology of the target species to better inform conflict mitigation. In Chapter I, …

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A Four-Pronged Approach To Addressing A Wild Pig Invasion In A Bottomland And Upland Forested Landscape, Tyler Scott Evans Aug 2023

A Four-Pronged Approach To Addressing A Wild Pig Invasion In A Bottomland And Upland Forested Landscape, Tyler Scott Evans

Theses and Dissertations

Among exotic species that are capable of invading, establishing, and reaching pest status, few pose the range of impacts to biotic (e.g., competition with native species, predation, herbivory, introduction of other exotics) and abiotic (e.g., soil, hydrology) ecosystem components that can be attributed to the wild pig (Sus scrofa). Despite the presence of wild pigs throughout the southeastern United States for centuries, new invasions continue to occur in previously uninhabited and often under-investigated landscapes, including bottomland and upland forests. The recent invasion of the Sam D. Hamilton Noxubee National Wildlife Refuge (hereafter, NNWR) in east-central Mississippi represents an …

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Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald Thomas Garrett Jul 2023

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald Thomas Garrett

Theses and Dissertations

Though the rate of deforestation has slowed in recent years, it remains a primary cause of land cover change within forest ecosystems. The Lower Rio Grande Valley, Texas (LRGV) has lost nearly 95% of its native thornforest since the early 1900’s due to agricultural and urban expansion. The focus of this study is to assess the current vegetative state of restored thornforest sites located in the eastern LRGV and to evaluate the use of cover crops during replanting of native seedlings. Our assessment of restored thornforest sites revealed actively restored sites demonstrated higher overall averages of richness, abundance, and diversity …

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Macroecological Patterns Of Frugivorous Fishes’ Diversity (Serrasalmidae) In The Amazon Drainage Basin, Karold Vivianna Coronado Franco May 2023

Macroecological Patterns Of Frugivorous Fishes’ Diversity (Serrasalmidae) In The Amazon Drainage Basin, Karold Vivianna Coronado Franco

Theses and Dissertations

The Amazon River drainage basin is known as the most biodiverse region in the world. Regarding freshwater fish, this region contains around 15% of the world's fish richness. The fish family Serrasalmidae have a variety of feeding preferences including Pacus (herbivores) and Piranhas (carnivores). Fruit eating fish species are evolutionarily the oldest species in the family and have a mutualistic interaction with flooded forests. Considering the diversity of feeding habits of the Serrasalmidae family, it represents an excellent model to study ecological questions related to factors that influence the spatial distribution of species and factors that contribute to the maintenance …

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The Response Of An Avian Community To Intercropping And Forest Management Practices In A Private Working Pine Forest, Rebecca Doyne Bracken May 2023

The Response Of An Avian Community To Intercropping And Forest Management Practices In A Private Working Pine Forest, Rebecca Doyne Bracken

Theses and Dissertations

Within managed pine forest systems, a plethora of bird species exist throughout the lifecycle of a stand akin to what may be experienced through post-disturbance regeneration in a natural forest system. I sought to address how breeding avian communities shift across time in response to stand aging and forest management, evaluate species-specific responses to stand conditions, investigate the responses of at-risk avian species to forest management, and determine avian non-breeding, over-wintering presence in a managed loblolly pine (Pinus taeda) forest. I conducted breeding bird point count and vegetation surveys within five stands of privately owned and managed pine forest in …

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Determining The Impact Of Post-Harvest Water Management On Chironomid Abundance, Agrochemical Biomass And Potential Trophic Biomagnification, Mason Thomas May 2023

Determining The Impact Of Post-Harvest Water Management On Chironomid Abundance, Agrochemical Biomass And Potential Trophic Biomagnification, Mason Thomas

Theses and Dissertations

Agriculture has diminished shorebirds’ natural habitat in the Mississippi Alluvial Valley. Remaining natural stopover sites are supplemented with agricultural fields during the fall and winter. This study evaluates the impact of 4 different post-harvest water management strategies on shorebird food abundance and potential agrochemical biomagnification. Chironomid samples estimated abundance, biomass, and chironomid agrochemical concentration in each field. A risk assessment of agrochemical biomagnification to shorebirds was made across all treatments. Of treatments represented on all study sites, winter treatment had greatest chironomid abundance and biomass. Models indicated that days since flood initiation, start date, and temperature are significant predictors of …

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Evaluation Of Nutrient Digestibility Of Weaned Calves From Early And Late Shedding Dams, Jennifer Keele May 2023

Evaluation Of Nutrient Digestibility Of Weaned Calves From Early And Late Shedding Dams, Jennifer Keele

Theses and Dissertations

Researchers have investigated several factors that could alter fetal growth, including nutrient restriction (Valiente et al., 2021), hair shedding (Gray et al., 2011), and extreme hot and cold temperatures (Davidson et al., 2022). Hot temperatures and increased humidity percentages in the southeast United States caused researchers to investigate the hair coats of Angus cattle in the commercial production setting. An improvement in fiber digestibility and calf birth and weaning weights has been observed in Angus dams that shed 50% of the winter hair coat by May (Gray et al., 2011; Burnett et al., 2021). Our objective of this experiment was …

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Habitat Effects On Scorpion Densities And Microhabitat Use By Centruroides Vittatus And Vaejovis Waueri In South Texas, Jonathan Beltran Apr 2023

Habitat Effects On Scorpion Densities And Microhabitat Use By Centruroides Vittatus And Vaejovis Waueri In South Texas, Jonathan Beltran

Theses and Dissertations

Co-existence between Centruroides vittatus and Vaejovis waueri is influenced by environmental factors that shape their habitats. Differences in surface activity frequency between the two species suggest differential microhabitat use. The observed frequency of scorpions using microhabitats in the Martinez Ranch and La Union Ranch were not significantly different from the expected frequencies. Frequency of scorpions observed using microhabitats in La Union South was significantly different from the expected frequency (P<0.001). Microhabitat use of catclaw was lower than expected and higher than expected for other vegetation. Conditional comparisons of microhabitats were significantly different among habitats (P<0.001), size classes were significantly different among microhabitats (P<0.001), and size classes were significantly different among habitats (P<0.01). Microhabitat use by scorpions on the ground was higher among all habitats. Scorpion use of ground and grass were different among size classes. Size class I-II scorpions had a higher frequency than size class III. Scorpion density for C. vittatus was significantly different among habitats (P<0.0001) and scorpion density for V. waueri was significantly different among habitats (P<0.0001). Centruroides vittatus was significantly higher in the Martinez Ranch and in La Union South. Vaejovis waueri was significantly higher in La iv Union South. Associations between plant densities and scorpion size classes were tested. Plant densities had a significant association with C. vittatus size classes I and II in the Martinez Ranch. Association between plants had a significant correlation with C. vittatus size classes I and IV in La Union Ranch. Association between plants had a significant correlation with V. waueri’s total density. These associations may suggest plant densities may have a synergistic effect on scorpion densities. Soil type composition for the different habitats was hypothesized to influence scorpion densities. Maps for each site were created to show soil type compositions. Soil type findings suggest that La Union South had the soil types with the lowest soil strength. Vaejovis waueri was shown to have a higher density in La Union South where soils are sandier. Results indicate that co-existence between C. vittatus and V. waueri is possible because competition is low through minimal overlap in microhabitat use and intraguild predation avoidance.

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Stage-Structured Predator-Prey Interactions In A Warming World: A Case Study In Riverine Rock Pools, Andrew T. Davidson Jan 2023

Stage-Structured Predator-Prey Interactions In A Warming World: A Case Study In Riverine Rock Pools, Andrew T. Davidson

Theses and Dissertations

Warming can impact predator-prey interactions through a variety of mechanisms. For example, warming can both alter the rate at which predators consume prey and the rate prey develop through vulnerable life stages. Thus, the overall effect of warming on consumer-resource interactions will depend upon the strength and asymmetry of warming effects on predator and prey performance. Here, we describe the consequences of these asymmetrical responses to temperature by first developing a simple stage-structured modeling framework, then applying that framework to predation of American rock pool mosquito larvae, Aedes atropalpus, by several common predators in riverine rock pools. We then …

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Quantifying Insect Emergence In Tidal Freshwaters And The Importance Of Aquatic Prey In Wetland-Dependent Songbird Diet, Samantha L. Rogers Jan 2023

Quantifying Insect Emergence In Tidal Freshwaters And The Importance Of Aquatic Prey In Wetland-Dependent Songbird Diet, Samantha L. Rogers

Theses and Dissertations

Insectivorous birds and their arthropod prey are experiencing widespread population declines, driven largely by anthropogenic disturbance and climate change. For wetland-dependent insectivores that consume a mixture of terrestrial and aquatic insects, understanding the availability, consumption, and nutritional qualities of aquatic diet subsidies is important for conservation. I use prothonotary warblers (Protonotaria citrea) as a model species throughout this work, because their breeding season aligns with aquatic insect emergence and they include aquatic insects when provisioning nestlings. In the first chapter, I estimate aquatic insect emergence from tidal freshwaters, which are understudied compared to nontidal systems. Using continuous field …

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Climate, Physiology, And Distributions: The Role Of Thermal Physiology In Biological Invasions, Sean D. Powers Jan 2023

Climate, Physiology, And Distributions: The Role Of Thermal Physiology In Biological Invasions, Sean D. Powers

Theses and Dissertations

Climate is a primary factor influencing species range dynamics, particularly for ectotherms whose body temperature is closely tied to the surrounding conditions. While range shifts of ectotherms are attributed to climate warming, the mechanism driving these shifts are not well understood. Studies in macrophysiology demonstrate that the interaction of climate with thermal physiology plays a key role in determining large-scale spatial and temporal patterns for many temperature-sensitive physiological traits. This work has revealed a clear relationship between thermal tolerance breadth and range size. However, more recent analyses of this relationship demonstrate that thermal tolerance breadth only provides a partial explanation …

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Patterns, Mechanisms, And Characterization Of Carbon Cycling Stability Following Partial Forest Disturbance, Kayla C. Mathes Jan 2023

Patterns, Mechanisms, And Characterization Of Carbon Cycling Stability Following Partial Forest Disturbance, Kayla C. Mathes

Theses and Dissertations

Among the most essential questions in the era of climate change is how the forest carbon (C) cycle will respond to an increase in the extent of biotic disturbances from insects and pathogens. While research has focused on stand-replacing disturbance regimes, less is known about C cycling stability following partial disturbances that produce gradients of disturbance severity. Belowground C cycling responses to disturbance are especially poorly understood, even though temperate forest soils contain up to 50% of total ecosystem C and soil respiration (Rs) accounts for more than half of temperate forest C loss. Interpreting trends and mechanisms …

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Plant Trait Effects On Tidal Wetland Methane Emission, Adam M. Dunn Jan 2023

Plant Trait Effects On Tidal Wetland Methane Emission, Adam M. Dunn

Theses and Dissertations

High rates of carbon (C) sequestration exhibited by coastal wetlands is an important natural climate solution to global environmental change. At the same time, however, wetlands are the largest natural source of methane (CH4) to Earth’s atmosphere, a potent greenhouse gas that influences the global climate. Wetland CH4 emissions display high degrees of uncertainty in accounting for spatial and temporal variations in emissions due to the complex interactions between biotic and abiotic factors that influence methane production and transport, in addition to simultaneous influences from climate-driven effects on wetlands such as rapid sea level rise and increased …

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Salinization Impacts On Heterotrophic Respiration, Ecosystem Respiration, And Plant Productivity In Tidal Freshwater Marshes, Kelsie J. Moses Jan 2023

Salinization Impacts On Heterotrophic Respiration, Ecosystem Respiration, And Plant Productivity In Tidal Freshwater Marshes, Kelsie J. Moses

Theses and Dissertations

Tidal freshwater marshes have preserved substantial stocks of soil carbon, which represents carbon dioxide that is no longer in the atmosphere. There is conflicting evidence in the literature about how disturbances such as sea level rise and associated wetland salinization impact the accumulation and long-term stability of this stored carbon. The goal of this experiment was to quantify how salinization impacts total ecosystem respiration and its component parts, autotrophic and heterotrophic respiration. This was a microcosm experiment using a C4 plant (Spartina cynosuroides) grown in soil derived from C3 plant matter and exposed to different salinities (0 to …

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