Digital Commons Network^™

Ecology And Evolution Of Social Information Use, Clare T. M. Doherty

Dartmouth College Ph.D Dissertations

Sociality is a strategy many animals employ to cope with their environments, enabling them to survive and reproduce more successfully than would otherwise be possible. When navigating their environments and making decisions, social individuals often use information provided by conspecifics (in the form of social cues and signals), thereby increasing the scope and reliability of the information they can gather. However, social information use may be influenced by many factors, including key differences in context across the physical and social environment. My thesis asks and answers a series of questions regarding the trade-offs in social information use across different contexts, …

Niche Overlap In Sympatric Rocio (Teleostei: Cichlidae) Of Guatemala, Cesar Estuardo Fuentes Montejo

College of Science and Health Theses and Dissertations

Rocio is a small genus of Neotropical freshwater fishes that is distributed in Atlantic drainages of northern Middle America. Two species in the genus exhibit sympatry in the Río Dulce basin (in Izabal, Guatemala), where one species is endemic (R. spinosissima), while the other only includes this area as part of a larger geographic range (R. octofasciata). Unfortunately, the ecology of these species has been poorly studied. This study sought to determine the ecological and morphological differences between these two closely related sympatric freshwater fishes. We hypothesized that R. octofasciata would exhibit greater ecological and morphological …

Consequences Of Biofilm Architecture On Vibrio Cholerae Ecology And Life History, Benjamin Ray Wucher

Dartmouth College Ph.D Dissertations

The diversity of microbes and the environments they inhabit are staggering. In many of these environments, bacteria have evolved to form sessile surface attached communities called biofilms. These biofilms have wide reaching impacts from importance in global carbon cycling, to persistent catheter infections, to biofouling and wastewater treatment. While many species of microbes form biofilms to survive in their environment, the architectures of these structures vary widely between organisms. Even though a great deal of work has been done to understand bacterial communities and their functions, little work has examined how the spatial aspects of biofilm architecture can affect the …

A Study Of Red Snapper (Lutjanus Campechanus) Ecology In The Northern Gulf Of Mexico And The Effect Of Variable River Outflow Using Stable Isotope Analysis Of The Food Web And Eye Lenses, Caitlin C. Slife

Dissertations

In the Mississippi Bight and surrounding waters, river outflow impacts the basal resources of the Red Snapper food web, altering carbon sources and impacting prey and predator isotopes. In this study, the impact of riverine outflow on nutrients, particulate organic matter (POM), and physical water parameters on Red Snapper and their food web was analyzed using stable isotope and stomach content analysis over 5 years. The Mississippi, Pearl, Pascagoula, and Mobile rivers were included in the analysis of river impact. The Mississippi and Mobile rivers were found to significantly impact nutrients and POM in the region. River outflow was also …

Characterizing Habitat Suitability For Gulf Sturgeon (Acipenser Oxyrinchus Desotoi) In Southern Louisiana, Jenna N. Brogdon

LSU Master's Theses

A generalized additive modeling (GAM) framework was used to characterize fish-habitat relationships and develop habitat suitability maps to predict spatiotemporal and ontogenetic shifts in Gulf sturgeon distribution within an impacted estuary in the northern Gulf of Mexico, Lake Pontchartrain. Gulf sturgeon (n = 103) were fitted with acoustic transmitters in the Pearl River during the early summer and fall from 2013 to 2018, and an array of acoustic receivers (n = 81) was used to monitor Gulf sturgeon habitat use and movement in the estuary from 2016 to 2019. Daily presence data from the telemetry array were paired with environmental …

Effects Of Mass Death On Community Structure And Ecosystem Function, Abby Kimpton Jones

Theses and Dissertations

Death and decomposition are natural processes that are generally well-understood. However, large events of death, such as mass mortality events (MMEs) are increasing in frequency and their impacts on the ecosystem are largely unknown. These events may have both bottom-up effects from increased nutrient input as well as top-down effects from loss of an ecological functional group by the affected population. Different functional MMEs may result in different top-down effects, creating cascading effects. In Chapter 1, I test the hypothesis that scavenger and herbivore simulated MMEs generate novel bottom-up and top-down effects. Results indicate that MMEs have a significant effect …

Quantifying Aboveground Biomass In A Tropical Forest Using A Lidar Waveform Weighted Allometric Model, Alejandro Rojas

Theses and Dissertations

Our knowledge of the distribution and amount of terrestrial above ground biomass (AGB) has increased using lidar technology. Recent advancements in satellite lidar has enabled global mapping of forest biomass and structure. However, there are large biases in satellite lidar estimates which impacts our understanding of carbon dynamics, particularly in tropical forests.

Ni-Meister et al. (2022) developed a lidar full waveform weighted height-based allometric model which produced very good results in temperate deciduous/conifer forest in the continental US. The purpose of this study was to evaluate this biomass model in an African tropical forest using the Land Vegetation and Ice …

Regional-Scale Climate-Induced Variation In Ant Physiology And Morphology, Daniel E. Murphy

Biology Theses

The biology of ectotherms such as insects is influenced by ambient thermal conditions. Ants are a ubiquitous and ecologically important group of insects and are well-established as bioindicators of thermal conditions. Ants are sensitive to the thermal extremes that vary with latitude, elevation, and land use, and these thermal gradients influence their spatial and temporal distributions. As a result, ants have evolved physiological and morphological thermal adaptations in response to the thermal environment of their habitats. These adaptations include increased physiological and morphological tolerance for temperature extremes. In Western New York (WNY), temperatures are temporally and spatially heterogeneous, changing with …

Competing Behaviors Of Thermoregulation And Ambush Foraging In The Timber Rattlesnake (Crotalus Horridus Horridus): A Mechanistic Assessment Of Thermal Conduction, Larry K. Kamees

Graduate Theses and Dissertations

The interaction between the biophysical environment and ectotherm morphology elicits behaviors designed to maintain internal body temperature (Tb) within a range that promotes physiological functions. The short-term requirements of mass (energy requirements) and heat balance are subject to tradeoffs imposed by the organisms current physiological (heat and mass budgets) and environmental (biophysical, demographic, social, and predation) constraints and available resources. In temperate forests, extreme temperatures are common in summer even with intermittent sun exposure due to dense canopy cover. In Spring and Fall, temperatures can range from below freezing to 35 ℃ in 24 hrs. An ambush predator like the …

Disturbance Ecology Of The Sonadora River Rock Pool Insect Assemblage At Luquillo Experimental Forest, Puerto Rico, Patrick Gilkey

Master's Theses

Freshwater rock pools can serve as habitat for aquatic insects. Flash-flooding can have profound effects on insect communities in streams and rivers, but these effects have not been studied on freshwater rock pools. The goal of this thesis was to describe ecological patterns of the Sonadora River rock pool insect community at the Luquillo Experiment Forrest, Puerto Rico, specifically in response to intense flash-flooding, and then perform experiments to elucidate possible processes to explain those patterns. The rock pools contained primarily three taxa of Dipteran (true-fly) larvae, in order of decreasing abundance, 1) a newly discovered species of ceratopogonid (biting …

Distribution And Ecological Function Of Pacific Lamprey In The San Luis Obispo Creek Watershed, Parker Kalan

Master's Theses

Pacific lamprey (Entosphenus tridentatus) is an endemic species to coastal watersheds along the Pacific Rim in North America and Asia. The species' geographic distribution is retracting and has not been mapped precisely, and the ability for the species to provide ecosystem services, such as water filtration, for supporting watershed management has not been tested. The San Luis Obispo Creek watershed, California, USA is at the southern end of Pacific lamprey’s retracting distribution, and the San Luis Obispo watershed is impacted by degraded water quality, making investigation of Pacific lamprey in the San Luis Obispo Creek watershed of direct …

Distribution Patterns Of The Invasive Mussel Arcuatula Senhousia In Mission Bay, San Diego, California: Effects Of Sediment Grain Size And Byssus Thread Production On Predation, Samantha Ahlman

Theses

The ability of bivalves to avoid predation by using defensive behaviors such as burrowing and byssus production may vary depending on the sediment characteristics of a given habitat. The varying sediment characteristics that change with water velocity within estuaries may influence the distribution of bivalves and limit them to areas that optimize their ability to defend against predators. We examined the distribution patterns of the invasive Asian date mussel Arcuatula senhousia relative to the sediment grain size distribution in Mission Bay, an urban estuary located in San Diego, California, USA. Mussels and sediment were collected using an Ekman grab at …

Climate-Related Declines In Reproductive Output In A High-Elevation Population Of Ground Squirrels, Kayleigh Little

Undergraduate Honors Theses

Beginning in the 1900s, changes in climate have resulted in an increase in global temperatures. This warming has driven behavioral and demographic changes within a multitude of species worldwide. Historically, small mammal populations have responded to changes in temperature by adjusting their geographic ranges. As temperatures rise, high-elevation populations may no longer be able to adjust as they have before. In this study, we evaluated possible effects of climate change on a high-elevation population of Belding’s ground squirrels (Urocitellus beldingi) at Tioga Pass in Northern California. We used local climate data and long-term population data from 1994 to …

Detection, Occupancy, Abundance, And Mercury Accumulation Of The Alligator Snapping Turtle (Macrochelys Temminckii) In Texas, David Rosenbaum

Electronic Theses and Dissertations

Land use practices and physical alterations of ecosystems result in habitat loss and fragmentation, while chemical alterations, such as pollutant input, reduce habitat quality and health of exposed organisms. Here, I investigated the effects of watershed- and local-scale environmental variables on the occupancy, abundance, and mercury accumulation of a threatened aquatic species (Macrochelys temminckii, i.e., alligator snapping turtle) within the southwestern periphery of its distribution. Hierarchical modeling suggested the distribution of the species is more affected by watershed-scale land-cover than local habitat, and provided a baseline estimate of average species abundance across its range in eastern Texas. Abundance …

Fire And Periodical Cicadas: Impacts On Soil Nutrients And Understory Plant Germination, Andrea Gamache

Master of Science in Integrative Biology Theses

Purpose

A compound disturbance, composed of a prescribed fire and a periodical cicada emergence, occurred in northern Georgia in the summer of 2021. Independently these disturbances have substantial effects on the surrounding ecosystems. This study investigated the collective impact on soil composition and seed germination.

Methods

Through the soil analysis of cicada turrets, burned soil, and unburned soil, we hope to understand the composition of each soil type. Additionally, a 2 x 2 factorial study was performed with those same samples, providing insight into the impact on seed germination these disturbances have. The two factors were between burned and unburned …

Discovery Of Truffles (Tuber Species) In North Mississippi Pecan Orchards, Scout Hodges

Honors Theses

This thesis describes a study conducted in the years 2019-2022, which aimed to discover a new species of truffle in the state of Mississippi. Tuber lyonii, more commonly referred to as the “pecan truffle,” is an ectomycorrhizal fungus found on the roots of pecan trees in much of the southeastern region of the United States. Though there are many truffles native to the United States, the pecan truffle is one of the few that has been found to have high culinary value. Given the plethora of pecan orchards in the state of Mississippi, I decided to search for evidence …

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 …

Evaluating The Ecological Relationships Among Beauveria Bassiana, Kudzu Bug And Kudzu, Kassie L. Hollabaugh

Masters Theses

When kudzu bug, Megacopta cribraria, was identified in the United States in 2009 as an invasive species, populations began to establish, increase, and spread throughout the southeastern region at intense rates. Kudzu bug invades urban structures, causing unpleasant scenes for homeowners, and reduces crop yield, such as soybean. Kudzu bug caused about $2.8 million in soybean yield loss and treatment in Tennessee in 2020. Although initial spread was rapid throughout the southeastern U.S., spatial modeling has shown populations of kudzu bug are declining and reducing risk of crop damage to growers. These local and regional declines in populations appear …

Plant-Pollinator Communities Responsive To Local And Landscape Level Factors In Grassland Restorations., Aaron Sexton

Electronic Theses and Dissertations

As humans continue to degrade natural ecosystems via greenhouse gas emissions and habitat destruction, many species are being pushed to the brink of extinction. In hopes to offset this degradation, habitat restoration attempts to restore ecosystem function to an improved state resembling intact, remnant values. This is a difficult, but important, undertaking with factors to consider at multiple spatial and temporal scales. The restoration and conservation of pollinator communities has garnered heightened attention because of the valuable ecosystem services they provide. This dissertation investigates the local and landscape level factors of grassland restorations that influence plant-pollinator communities. I used a …

Assemblage Composition And Vertical Distributions Of Deep-Sea Anglerfishes (Suborder: Ceratioidei) Of The Northern Gulf Of Mexico, Kimberly S. Schmutz

All HCAS Student Capstones, Theses, and Dissertations

The bathypelagic zone, despite being the largest cumulative ecosystem on the planet, represents the largest data gap in biological oceanography. In a deep environment with no solar light and pressures so high that survival is impossible for most marine organisms, some species have been able to adapt and overcome these challenges to radiate into diverse and successful taxa. Among the most notable of these successful taxa are the deep-sea anglerfishes (Lophiiformes: Ceratioidei). Ceratioid anglerfishes possess unique adaptations such as a symbiotic bioluminescent lure (females) and extreme dwarfism (males) that make them a particularly interesting group to study. Despite this research …

Trophic Ecology Of A Dominant Mesopredatory Fish Family (Alepisauridae) In The Western North Atlantic Revealed By Stomach Content And Stable Isotope Analysis, Ellyn Willse

All HCAS Student Capstones, Theses, and Dissertations

The mesopelagic zone of the ocean is gaining increased notice due to its potential for commercial value and the lack of knowledge of its ecosystems. Lancetfishes, Alepisaurus spp., are large mesopelagic predators and common bycatch species in commercial fishing operations that potentially play a role in connecting epipelagic and mesopelagic waters and may be a source of carbon from near the surface to the mesopelagic. While little is known about the behavior and biology of Lancetfishes, they share many food sources, and are themselves a food source for important commercial fisheries species such as tuna and swordfish. This study examines …

A Multi-Spatial Analysis Of Land Use Effects On Freshwater Mussels In The Upper Cuyahoga River And Tinkers Creek, Tamar Atwell

ETD Archive

Mussels are considered one indicator of good water quality in rivers, but over the past 20 years mussel populations have continued to decline, while water quality improves. According to the Ohio Environmental Protection Agency (OEPA), water quality in the Cuyahoga River is now within safe levels for all parameters. However, what are safe levels for humans may not be safe for mussels. An analysis of freshwater mussel populations in two similarly sized watersheds, the Upper Cuyahoga River and Tinkers Creek was conducted. Correlations of mussel abundance and diversity were assessed by multivariate GIS/remote sensing tools to contrast water flow rates, …

Analysis And Identification Of Lipolytic Bacterial Species For The Degradation Of Wastewater Lipids, Lindsay C. Smoak

Honors College Theses

The aim of this study was to isolate native bacterial strains from the wastewater treatment facilities of Statesboro, GA to identify their lipolytic activities. Obtained bacterial strains were further assessed via morphological and biochemical methods to determine their enzymatic capabilities. Use of the detergent Tween-20 in growth mediums was the first criteria to assess lipase activity, and these isolates were further investigated to quantitatively measure lipase presence and activity. Lipase protein was precipitated and dialyzed to perform a lipase activity assay, followed by Sodium Dodecyl Sulphate–Polyacrylamide Gel Electrophoresis (SDS-PAGE) to confirm the presence of the lipolytic enzymes. Sanger sequencing was …

Movement Patterns Of The Shovelnose Guitarfish (Pseudobatos Productus) And California Bat Ray (Myliobatis Californica) In The Southern California Bight, Annabel Gong

Theses

While the movement patterns of large elasmobranch species have been studied extensively, those of smaller, mesopredatory species remain understudied. The shovelnose guitarfish (Pseudobatos productus) and the California bat ray (Myliobatis californica) are among the least studied elasmobranchs in the Southern California Bight. This study quantified the broad- and fine-scale movement patterns of these species using passive acoustic telemetry. Twelve guitarfish were surgically implanted with coded acoustic transmitters at a known aggregation site off La Jolla (San Diego County), California, USA and tracked for 849.5 days each, on average. Six bat rays were also implanted here and tracked for …

Making Forests, Making Communities: An Ethnography Of Reforestation In Monteverde, Costa Rica, Megan Brown

Anthropology Theses and Dissertations

Reforestation is not just planting trees in the ground. More than net increase in forest cover, reforestation is a complex political endeavor undertaken by both humans and non-humans and a popular climate change mitigation tactic. However, little research has examined the dynamics between selection of specific reforestation strategies, health, and community resilience, particularly with attention to entanglements between the lives of both human and non-human forest dwellers. This ethnographic work, based on six months of in-person fieldwork and six months of digital ethnography, examines reforestation and forest relations in Costa Rica’s Monte Verde zone, a region which experienced widespread deforestation, …

Understanding The Genomic Influence And Virulence Capabilities Of Environmentally Isolated Vibrios, Shannon Elizabeth Pipes

Theses and Dissertations

The genus Vibrio consists of Gram-negative bacteria that possess a curved rod shape and are routinely isolated from estuarine and coastal salt water. Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus are the major three species that contribute to human disease worldwide, and a variety of other Vibrio species contribute to persistent problems in the aquaculture and fishing industries. The CDC estimates that vibrios cause 80,000 cases of disease each year in the United States alone, however, this number is thought to be underestimated, since some disease is only self-limiting, meaning patients may not seek medical treatment and have …

Crassostrea Gigas Invasion In Southern California: Macrofaunal Diversity And Local Community Impacts Of Ecosystem Engineers On Estuarine Habitats, Noah Jansen-Yee

Theses

Many marine ecosystems are facing the growing threat of biological invasions. These invasions can have a variety of different impacts on ecosystems and their inhabitants. The Pacific oyster, Crassostrea gigas, is currently in the relatively early stages of invasion in San Diego estuaries. Crassostrea gigas is a large, filter-feeding bivalve that forms dense oyster beds on hard substrate. These oysters are known to outcompete native counterparts and drastically alter habitats where they are present. Crassostrea gigas is an ecosystem engineer that, through shell creation and formation of a dense oyster matrix, impacts ecosystems in a variety of direct and indirect …

Geographic Range Size As A Predictor Of Dispersal-Dependent Behavioral Traits In Two Clades Of A Terrestrial Salamander, Teah Evers

Masters Theses

Animal movement has the potential to affect diverse processes within ecology and evolution including range expansion, gene flow, adaptation, and speciation. Two aspects of animal personality that are germane to dispersal are exploratory and aggressive behavior. These behavioral categories may represent a trade-off such that energy invested in territorial defense leaves little energy for movement and dispersal. The Eastern Red-backed Salamander (Plethodon cinereus) is a wide ranging, dispersal limited, terrestrial salamander with well documented phylogeographic divisions. I examined dispersal-relevant behavioral traits within two clades of P. cinereus with disparate geographic ranges. The Northern Clade (NC) has a range extending from …

Responses Of Arthropods To Fire And How Pollinators And Pollination Services Are Affected By Fire Severity, Blyssalyn V. Bieber

Electronic Theses and Dissertations

Fires impact ecosystems globally and due to climate change, there are shifts in fire regimes that impact ecological communities which provide essential ecosystem services. Focusing on arthropods, fire can influence this ubiquitous animal group in various way. We performed a comprehensive meta-analysis evaluating how fires impact differing arthropod functional groups. We found that overall, fire negatively effects community level responses for most functional groups with herbivores as the only exception showing some positive effects of fire. We also studied mixed-severity fires that burned >20 years ago and compared floral visitor communities across fire severities. We implemented a pollinator exclusion experiment …

Bottom-Up Effects Of Degradation Outweighs Stabilizing Potential Of Omnivores, Hannah Marie Moore

Murray State Theses and Dissertations

Anthropogenic activities have led to degradation in streams throughout much of Western North America. In particular, cattle grazing has led to a loss of riparian vegetation resulting in higher water temperatures and an increase in nutrient runoff. The effects of degradation on food quality and quantity for aquatic consumers could have large implications for stream communities. Since omnivores feed at multiple trophic levels, they may be resilient to altered food webs, which may allow them to stabilize communities in degraded environments where resources have been reduced. To test the hypothesis that omnivores positively impact community stability in degraded conditions, I …