Digital Commons Network^™

Demographics, Sexual Dimorphism, And Ecological Aspects Of Ambystoma Annulatum (Ringed Salamander) In Northwest Arkansas, Usa, Brian M. Becker

Graduate Theses and Dissertations

The need to study and monitor amphibian populations is increasing along with the threats to their population stability and persistence in nature. Northwest Arkansas is one of the fastest growing areas in the nation and with that growth comes rapid changes in land use, massive alterations to habitats, habitat loss, and the introduction of nonnative plants and animals. Ambystoma annulatum (Ringed Salamander) is an Ambystomatid endemic to the Ozark and Ouachita Mountains of southern Missouri, northern and western Arkansas, and eastern Oklahoma giving it a relatively small distribution compared to most Ambystoma. Therefore, Arkansas constitutes a significant portion of the …

Population Dynamics And Habitat Use By Gray Bats In An Anthropogenically Altered Landscape, Haley Price

Electronic Theses & Dissertations

Habitat loss resulting from land use change is among the greatest threats to biodiversity. Yet, in some cases, imperiled wildlife species may benefit from anthropogenic disturbance. The expansion of urbanization, agriculture, renewable energy, and mining practices impact conservation efforts for threatened and endangered bat species, and particularly species that are affected by white nose syndrome (WNS). The federally endangered gray bat (Myotis grisescens) is a cavernicolous species that is susceptible to WNS. Due to their unique roosting and foraging requirements, gray bats inhabit a small portion of the accessible caves within their geographic range. As habitat loss persists, …

Population Ecology Of The Diamondback Terrapin At Their Northern Range Limit, Patricia M. Levasseur

Doctoral Dissertations

This dissertation research focuses on the population ecology of the northern diamondback terrapin (Malaclemys terrapin terrapin) in Wellfleet Bay, MA. The northern diamondback terrapin is a Massachusetts-threatened turtle species restricted to estuarine environments. With a range from Cape Hatteras, North Carolina to Massachusetts, Cape Cod Bay is the northernmost part of the subspecies range. Mass Audubon’s Wellfleet Bay Wildlife Sanctuary has been using capture-mark-recapture (CMR) methods since 1980 marking over 3,000 individuals; however, low detection rates and variable search effort have resulted in unreliable population estimates not suitable for informing conservation practices within the bay. Low sample sizes, …

Ecology And Conservation Of Grey Crowned Cranes (Balearica Regulorum) In Tanzania, Bridget Amulike

Doctoral Dissertations

Grey-crowned cranes (Balearica regulorum) are listed as endangered and their population throughout Africa has declined by 50% from the period of 1985–2004. The major causes for their population loss are mainly linked to habitat loss and the illegal capture of live birds and collection of their eggs and other parts. Currently, throughout Africa, little has been done to study and protect grey crowned cranes. In this study, I incorporated local people’s knowledge, using survey questionnaires to investigate the distribution of grey crowned cranes in Arusha, Kilimanjaro, Singida, and Mbeya Region in Tanzania. I also investigated the perception and attitudes …

The Effects Of Commercial Harvest On The Density And Demography Of Aquatic Turtles In Arkansas, Andrhea Darleen Massey

Graduate Theses and Dissertations

The United States is home to the second highest concentration of turtle species in the world, after Asia. As of 2018, there are 57 turtle species recognized within the US, 40% of which are listed as threatened or endangered, with the primary threats to population persistence identified as over-consumption and/or habitat loss. Within the US, the Mississippi Alluvial Valley (MAV) region represents the second highest turtle species richness, after the Mobile River Basin. The MAV region of Arkansas is one of the least regulated in terms of commercial aquatic turtle harvest and has undergone large-scale habitat conversion from bottomland hardwood …

Population Genetic Analyses Of Arctic Char (Salvelinus Alpinus) Life History Types In Nettilling Lake & Amadjuak River Ecosystem: A Test Of Reproductive Isolation, Chen Liu

Electronic Theses and Dissertations

A great number of studies have identified strong genetic differences between sympatric anadromous and resident populations of Salmonidae. However, Arctic char (Salvelinus alpinus) migratory phenotypes in the Nettilling Lake and Amadjuak River ecosystem in Nunavut, Canada have not been genetically characterized, and it remains unclear if distinct genotypes and phenotypes associated with migratory life history differences are maintained through reproductive isolation, and they have been assumed to be sympatric populations, or co-occurring populations. Co-occurring Arctic char (n=225) were sampled from eleven sites along the Amadjuak River in 2014 and 2015. Twelve microsatellite loci were used to quantify genetic variation among …

Noninvasive Genetic Sampling With A Bayesian Spatial Capture-Recapture Analysis To Estimate Abundance Of Roosevelt Elk (Cervus Canadensis Roosevelti), Makenzie Henk

Cal Poly Humboldt theses and projects

Determining abundance of Roosevelt elk (Cervus canadensis roosevelti) in central Humboldt County, California has presented a unique challenge to wildlife managers due to the dense forest habitat and the animals’ elusive behavior. As the elk population has increased, so has human-wildlife conflict, and wildlife agencies need efficient and repeatable methods for determining abundance to inform management decisions. Traditional monitoring methods such as helicopter surveys are ineffective due to low sighting probability and strong behavioral responses to the aircraft. They also often lead to biased sex ratios when the distribution of males and females varies across the landscape. Non-invasive …

Sea Level Rise Vulnerability Analysis Of Mangrove Ecosystems Using Gis, Kayla Caldwell

HCNSO Student Theses and Dissertations

Climate change is accelerating beyond what is natural due to excessive emissions from human activities. The sea level has been rising for many years and is currently at a rate of 3.6 mm/yr. Mangroves are known to only keep pace with a sea level rate of less than 1.2 mm/yr. Mangroves are particularly vulnerable to rising sea levels if they are not able to keep pace through vertical sediment accretion or inland migration. To test the vulnerability of the south Florida mangrove ecosystems to sea level rise, this study analyzed changes in the mangrove forest coverage of the Oleta River …

Mammal Species Inventory Using Various Trapping Methods In Zone 4 Of Billy Barquedier National Park, Belize During Rainy Season, Mersady Redding

Animal Science Undergraduate Honors Theses

Belize is a small country, but it is extremely ecologically diverse. Based on the few studies conducted in Belize, the abundance of mammals is low but diversity is high. Particular findings note the number and identity of species differed between four sites in the Maya Mountains of Belize, indicating that a data set from a single site is not representative of the Neotropical region. Insufficient data is available to estimate current species richness of many areas in Belize, including Billy Barquedier National Park (BBNP). The objective of this study was to explore trapping and documentation methods of terrestrial mammals in …

Adult Atlantic Sturgeon Population Dynamics In The York River, Virginia, Jason E. Kahn

Graduate Theses, Dissertations, and Problem Reports

Sturgeon first appear in the fossil record in the Triassic Period just over 200 million years ago and are among the most primitive of the bony fishes. Despite their large size and historic presence along the East Coast, Atlantic sturgeon were not targeted for their meat and caviar as a commercial fishery until 1880. By 1905 they had declined to less than one percent of their pre-fishing abundance but the fishery continued. Prior to 1980, there had been very little research on Atlantic sturgeon, primarily limited to documenting landing location and poundage, maximum longevity, or weight of eggs per fish. …

Effect Of Reinforcement Selection On Mate Selection Rates Of Gambusia Affinis And Gambusia Holbrooki, Molly Stephens

Honors Theses

This study was conducted in order to investigate the effects that reinforcement selection has on non-hybridized and hybridized populations of two separate species of Gambusia (G. affinis and G. holbrooki). In order to examine if organisms from a population that had been previously exposed to hybridization would choose mates so as to not produce species hybrid offspring, 29 trials consisting of 9 different mate preference combinations and 87 individuals were recorded and analyzed. Once mate preference was determined for each female used in each trial, the effect that reproductive isolation had on reinforcement in hybrid zones was analyzed. The results …

Surveillance Of South Dakota Mosquito Abundance, Infection Rate, And Insecticide Susceptibility, Geoffrey P. Vincent

Electronic Theses and Dissertations

The aim of this dissertation was to survey and evaluate the abundance, infection rate, and insecticide susceptibility of mosquito fauna present in South Dakota. Mosquito surveillance has been conducted across South Dakota to record and track potential West Nile virus (WNV) vectors from 2004 to 2017. The nuisance mosquito Aedes vexans was found to be the most abundant species overall in the state and most abundant in many of the regions. The WNV vector, Culex tarsalis, was found to be the second most abundant mosquito and the most abundant vector mosquito across the state. However, geospatial variation did exist between …

An Evaluation Of Trap-Neuter-Release Practices For Free-Roaming Cat Populations, Brian Gaston

Master's Theses

As of 2002, estimates of free-roaming domestic cat (Felis catus) populations exceeded 100 million individuals, throughout the United States. Many lost or abandoned cats will revert to living outdoors as free-roaming individuals. To try to control the abundance of free-roaming cats, trap-neuter-release (TNR) programs have been implemented across the United States. The goal of many TNR programs is to reduce cat populations by sterilizing the individuals to prevent breeding, while also providing food and water to the unconfined colony. However, wildlife conservationists question the effectiveness of TNR programs. The objectives of my study were to: determine the population size and …

Population Size And Habitat Association Of Etheostoma Nebra, The Buck Darter, Using Abundance Modeling In The Buck Creek System, Cumberland River Drainage, Kentucky, Harold Davidson Black

Online Theses and Dissertations

Etheostoma nebra (Buck Darter) is a recently described fish species confined to the Buck Creek system, Cumberland River drainage, Kentucky. A 2010-2012 survey of Buck Creek by Kentucky Department of Fish and Wildlife Resources personnel observed E. nebra at 2 of 47 historical sites. Within the entire system, individuals were found only in Flat Lick Creek around the confluence of two spring-fed tributaries, Big Spring Branch and Stewart Branch. The objectives of this study were to: (1) determine population size, demographics, and habitat association of E. nebra in Big Spring Branch and Stewart Branch, (2) evaluate habitat conditions both within …

Estimating Density And Residency Of Bottlenose Dolphins (Tursiops Truncatus) In Three Estuarine Sites In South Carolina, Jessica Nicole Conway

Electronic Theses and Dissertations

Of the three estuarine bottlenose dolphin stocks in South Carolina, two are considered data insufficient, with no minimum population estimate or assigned potential biological removal value. Additionally, the Northern Georgia Southern South Carolina Estuarine System (NGSSCES) stock’s boundaries are based on sighting data that do not extend to the full area encompassed by the boundary lines. In areas where stock boundaries are not clearly defined and data is insufficient for traditional methods of estimating abundance, density may provide insight into local distributions and serve as a proxy for actual abundance. Photo-identification surveys were conducted in three sites, representative of the …

Biology And Impacts Of Leech Infestation In Largemouth Bass (Micropterus Salmoides) In Back Bay, Virginia, Amanda Nicole Pomposini

Biological Sciences Theses & Dissertations

Back Bay is an oligohaline coastal bay in Southeast Virginia, USA. The Oregon Inlet along the Outer Banks of North Carolina is the only significant salinity source to the Bay via the Pamlico and Currituck Sounds of North Carolina. Today Back Bay is considered a brackish ecosystem with salinity of 2004, leeches have been observed in the oral cavities of Largemouth Bass (Micropterus salmoides) in Back Bay. Leeches (Myzobdella lugubris) have previously been documented in the oral cavities of largemouth bass in the Currituck Sound. In 2009, the Virginia Department of Game and Inland Fisheries (VDGIF) …

Development Of Novel Allele Specific Pcr Based Assays To Investigate The Contribution Of Cortisol To Metabolic Syndrome And It's Potential Implications In Depression Treatment, Justin Robert Salm

Honors Theses

The shared circuitries of depression and the stress response, regulated by the Hypothalamic-Pituitary-Adrenal (HPA) axis, implies that major depression may reflect dysregulations of the HPA axis. Previous studies find that that melancholic depression is accompanied by hyperactive HPA activity, anxiety, insomnia etc. Adversely, patients with atypical depression present CRH deficiency accompanied by lethargy and fatigue. According to the corticosteroid receptor hypothesis, HPA axis dysregulation that causes these variable phenotypic depressive moods may be attributed to defective GR expression or function. Multiple GR polymorphisms that could impact its expression or function have been identified. Due to limitations, it was not feasible …

Effects Of Variable And Changing Environments On Demography: Inferences From A Lesser Snow Goose Colony, David T. Iles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mean and variability of environmental conditions have changed as a result of human activity, and continued changes are predicted. The strongest effects on natural populations will often be channeled through species interactions, as shifts in species range limits and life cycle schedules will shift in relation to each other. These changes will often impact rates of survival, growth, and reproduction simultaneously, and these effects will likely differ across habitats.

In chapter 2, I used mathematical modeling and computer simulations to investigate the evolutionary significance of increasingly variable environments, and examine how evolutionary pressures change when multiple vital rates are …

Hybridization Dynamics Of A Newly Discovered Parrotfish Swarm In The Tropical Eastern Pacific, Robert Barron

Honors Projects

Hybrid zones and their dynamics are important in the understanding of the genetic basis of reproductive isolation and speciation. This study seeks to investigate the hybridization dynamics of a Scarus hybrid swarm within the Tropical Eastern Pacific (TEP) that includes four phenotypically distinct species: S. perrico, S. ghobban, S. rubroviolaceus, and S. compressus. Genetic and population structure analyses of four nuclear loci and a mitochondrial locus revealed that one of the four species, S. compressus, was the result of two different hybrid crosses: S. perrico ✕ S. rubroviolaceus and S. perrico ✕ S. ghobban. A …

Assessing The Rate And Extent Of Transgenerational Acclimation And Adaptation To Ocean Warming, Abby C. Nease

HCNSO Student Theses and Dissertations

A primary goal of climate change research is to determine if species will be able to persist in a warmer environment. Most studies predict climate change will cause many species to become extinct. However, these predictions are based on experiments where only a single life stage or generation of a species was exposed to predicted future conditions (i.e. shock treatments), and thus overlook the possibility of species adapting or acclimatizing to new environmental conditions over multiple generations. As a result, current projections of species persistence through climate change are likely to overestimate species extinction. In this study, the rate and …

Survival And Cause-Specific Mortality Of A Southeastern Kentucky Deer Population, Caleb Anderson Haymes

Theses and Dissertations--Forestry and Natural Resources

White-tailed deer are one of the most sought after game species in Kentucky. While much of the Commonwealth boasts high deer populations, those in southeast Kentucky are viewed as relatively low compared to other regions, even after a decade of restrictive doe harvest and multiple years of population supplementation via translocation. We studied survival and cause specific mortality of a local population of deer near the Redbird District of the Daniel Boone National Forest in Clay and Leslie County, Kentucky from January 2014 - January 2017. We estimated female annual survival at 0.89 (CI: 0.88-0.87), with an overall 3-year survival …

The Influence Of Canopy Cover And Climate On Early Life-Stage Vital Rates For Northern Red-Legged Frogs (Rana Aurora), And The Implications For Population Growth Rates, Kecly Mcharry

Cal Poly Humboldt theses and projects

Many amphibian species are in decline due to habitat loss and changing climates. Understanding how habitat characteristics and climate influence vital rates, and if they act in concert or in opposition can inform management decisions. This study investigated the potential interaction of canopy cover and climate on early stage vital rates of northern red-legged frogs. Demographic data were collected from sample populations in experimental canopy cover treatments across a latitudinal distribution. Rearing cages were used to estimate hatch success, and mark-recapture surveys to estimate tadpole survival. Ambient air temperature was used as an index of climate because it is easily …

Effect Of The 2013-2015 California Drought On Small Mammal Abundance And Diversity In Chaparral, Oak Woodland And Riparian Habitats, Nicole Desideri

Biological Sciences

Long-term biodiversity surveys are a useful tool for assessing the impacts of stochastic events on wildlife and their communities. A recent stochastic event to affect the state of California is the historic 2013-2015 drought. This drought, described as a one-in-one-thousand year event, brought precipitation to a historic low; the statewide rainfall reaching 34% below average (Swain et al. 2014). While humans are feeling the impact of this water shortage, the effects on native ecosystems and wildlife populations are poorly documented. Baseline small mammal biodiversity data collected in 2011, before the drought, allows us the opportunity to study the impacts of …

Impacts Of Forest Disturbance On Small Mammal Distribution, Allyson Lenora Degrassi

Graduate College Dissertations and Theses

Natural habitat in the eastern United States has diminished over the past century because of the effects of invasive species. Both plant and animal invaders can alter habitat structure and may decrease survival of native species. The degree to which an invasive species alters ecosystem function depends on the functional characteristics of affected species and the resulting cascading effects. The loss of important native species, such as foundation species, can potentially influence the structure and distribution of animal communities because of the foundation species' unique ecosystem roles. The foundation species concept is relatively new to the terrestrial ecology and the …

Non-Suitable Habitat A Cause For Declining Bobolink Populations In Northern Utah, Bethany Q. Unger

Undergraduate Honors Capstone Projects

Bobolink, Dolichonyx oryxivories, populations are declining in Utah. I characterized the habitat conditions of known bobolink nesting sites in Utah and compared these conditions to those for nest sites in Wisconsin where bobolinks are abundant. My habitat assessment included identifying vegetation species, vegetation cover, pH, temperature, and precipitation at each site location. Vegetation cover different between Utah and Wisconsin nest sites. Precipitation varied for both locations with no correlation between water availability and bobolink presence. One possible driver for the reduction in bobolinks throughout Utah is the drastic increase in temperature. Other possible external factors include livestock grazing, edge distance, …

Population Structure And Habitat Association Of Aquatic Testudines In Quivira National Wildlife Refuge, Jeffrey T. Seim

Master's Theses

I researched aquatic turtle population structure and habitat association of the turtles of Quivira National Wildlife Refuge (QNWR), in central Kansas. This group of organisms was focused on because of the lack of baseline knowledge and understanding of species presences, population sizes, structure, or habitat use on the refuge. I selected wetland units for sampling based on water permanence and quality of habitat. I then deployed baited hoop traps on these wetland units from April 24 to July 4, 2015. Captures were identified to species, measured, marked, and then release. Schnabel Multiple Census Method and Combined Percent Estimates were used …

Genetic Diversity, Population Structure, And Evolution Of Virulence In Toxoplasma Gondii, Elliot Keats Cullen Shwab

Doctoral Dissertations

Toxoplasma gondii is among the most widespread eukaryotic pathogens known. It chronically infects approximately one third of the world’s human population and has been isolated from an extremely diverse array of globally distributed mammals and birds. Understanding the structure of the worldwide T. gondii population enhances our understanding of the factors that have shaped that structure and led to the proliferation of one of the most evolutionarily successful pathogens on Earth. Herein we collate genotypic data from global isolates, demonstrating that T. gondii possesses a unique population structure in which only a small number of genotypes dominate throughout the northern …

Population And Community Dynamics Of Freshwater Decapods In Response To Ecological And Anthropogenic Factors In Subtropical Streams In The Caribbean, Omar Perez-Reyes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Historically, cities were established in close proximity to the richest agricultural lands and freshwater resources. In tropical islands, urbanization occupies a large percentage of land use along streams and rivers and strongly affects the biota and habitat quality. I studied freshwater decapod population and community dynamics in tropical streams of Puerto Rico across human and elevational gradients. I found that: 1) streams with less urbanization had higher decapod species richness and population sizes than the highly urbanized streams; 2) changes in the food webs in the streams are the result of the influence of changes in land use and environmental …

Impact Of Development On Freshwater Turtle Populations Of Coastal South Carolina: An Examination Of Land Use And Road Density, Andre Dominguez

Electronic Theses and Dissertations

Previous studies (Haxon 2000; Steen and Gibbs 2004; Marchand and Litvaitis 2004; Aresco 2005) have demonstrated that urbanization and development have disproportionally adverse affects on female turtles. In order to test this paradigm I caught 301 turtles (primarily Trachemys scripta scripta) in ten ponds (5 impacted and 5 unimpacted) across coastal South Carolina. Not only do coastal South Carolina turtles not follow the same male biased pattern of many other studies, there was an overall female bias (154:95). Turtle metrics were between the types of sites existed as well, indicating larger/older population of turtles in unimpacted sites. Water quality parameters …

Carnivore Diet Identification Through Scat And Genetic Analysis In Namibia, Africa, Alicia J. Walsh

Honors Theses and Capstones

Worldwide the cheetah population is declining making them Africa’s most endangered large cat. Namibia, Africa currently has the largest population of cheetahs in the world. During the summer of 2014, I did scat analysis of carnivores on the property of the Cheetah Conservation Fund (CCF) in Namibia in order to better understand the predators that compete with the cheetah and how the ecosystem works as a whole. I worked at CCF for nine weeks to analyze the diets of carnivores in the area through genetic and scat analysis. Analyzing carnivore feces would ultimately identify the diet of various carnivores in …