Population Biology Commons^™

A Genetic Analysis Of The Rare Endemic Astragalus Ripleyi Barneby, Juan Antonio Jaramillo-Chico

Master's Theses

Astragalus ripleyi Barneby is a rare endemic species found in the San Luis Valley of the southern portions of the Rocky Mountains in Colorado and New Mexico. Though not federally listed as endangered, the species is on the Bureau of Land Management’s Sensitive Species List, warranting protection and continued management. This study aims to provide information about the genetic health of the species to inform conservation efforts and provide updated management recommendations. A genetic health analysis was conducted investigating the levels of diversity present in the species, how genetic diversity is structured across the known range of the species and …

Investigating Cryptic Diversity In The Hawaiian Endemic Plant, Psychotria Mariniana (Rubiaceae), Uyen Thi Hoang Nguyen

Master's Theses

Islands, with their isolation and steep environmental gradients, serve as natural laboratories for studying speciation. Molecular phylogenetic and population genetic methods utilizing Next-Generation Sequencing (NGS) have revolutionized our ability to document patterns of genetic divergence and diversity. Cryptic diversity, genetically distinct populations that were previously unrecognized as unique, and cryptic speciation, where divergent genetic populations may be deserving of status as unique species, have been observed in many taxa. The Hawaiian Islands provide an ideal setting for studying divergence and speciation due to their extreme isolation, known ages, and volcanic origin. Previous work has investigated the evolutionary relationships of the …

Morphological Variation Of Lingual Glands In Wild American Alligator (Alligator Mississippiensis) Populations, Benjamin Angalet

Master's Theses

American alligators (Alligator mississippiensis) inhabit diverse aquatic ecosystems including freshwater wetlands, swamps, and estuarine rivers. As apex predators, their physiological resilience has implications for ecosystem stability and long-term conservation. With projected sea-level rise and increasing saltwater intrusion into coastal freshwater habitats, understanding the osmoregulatory capacity of alligators is increasingly important. Unlike marine-tolerant crocodilians such as the saltwater crocodile (Crocodylus porosus), which possess specialized salt-secreting lingual glands in addition to renal and cloacal mechanisms, the morphology and physiological significance of lingual glands in wild American alligators remain poorly understood. This study examined lingual gland morphology and plasma …

Pollinator Plant Communities Within Restored Montane Longleaf Pine Ecosystems, Hanen Van Rossem

Master's Theses

Historically the fire-dependent and biodiverse longleaf pine (Pinus palustris) ecosystem was the dominant ecosystem of the Southeastern US. This ecosystem’s range was massively reduced due to land conversion and fire exclusion, causing the decline of many native species. Efforts to restore and protect longleaf pine stands are now ongoing with the goal of expanding habitat and refuge for threatened species. Differences in restoration practices and prior land use may influence the extent to which restored habitat patches can support pollinators and their plants. This study compared pollinator plant biodiversity between restored neighboring montane longleaf pine stands that differed in …

Tricolored Bat (Perimyotis Subflavus) Population Genetic Structure In The Southeastern United States, Laura Henderson

Master's Theses

Tricolored bats (Perimyotis subflavus) have experienced substantial population losses from white-nose syndrome (WNS), a disease caused by the pathogenic fungus Pseudogymnoascus destructans (Pd) which infects hibernating bats. Determining population genetic structure helps assess genetic diversity and the impacts of wildlife threats to populations. Pre-WNS data shows weak-to-negligible structure and panmictic P. subflavus populations at core portions of their range. However, current genetic data from their southeastern U.S. range is lacking. I sought to determine whether recent genetic data help resolve genetic structure among southeastern populations and assess genetic differences at two stages of impact: post-WNS and …

Geomorphic Assessment And Flow Modeling Of Pearl Darter (Percina Aurora) Habitat In The Pascagoula River Watershed, Malia Davidson

Master's Theses

Freshwater ecosystems are complex ecosystems driven by hydrologic, geomorphic, and biological processes. Considering both abiotic and biotic factors is important to understanding resident species habitat. Geomorphology is a known, but often neglected factor in habitat assessment for freshwater fishes. A crucial feature commonly seen in alluvial stream systems are sandbars, which are dynamic and variable sediment structures that are known to have many associated species. One such species is the Pearl Darter, Percina aurora, a federally threatened species that only resides in the Pascagoula River watershed. Despite its status, habitat preference remains unclear. To fill this knowledge gap, I …

Spatial And Abiotic Effects Of Urbanization On Small Mammal Communities, Bri Casement

Master's Theses

Urbanization, the phenomenon of increasing human population density and artificial structures, is known to decrease the richness, abundance, and diversity of native wildlife populations, fragment natural areas, and increase human and human-commensal animal interactions with wildlife. Dynamics of species persistence in habitat fragments is often understood in the framework of island biogeography theory (IBT), with habitat fragments being analogous to oceanic islands. Despite the conceptual similarities between oceanic islands in IBT and urbanized habitat fragments (fragment size, fragment age, and distance to immigration sources), there are important differences. In urban fragments, the matrix is not completely impassible, habitats within fragments …

Soil Bacterial Community Shifts In A Montane Longleaf Pine Restoration Site: Effects Of Dominant Herbaceous Species Removal, Prescribed Burn, And Changes In Season, Isabella K. Vahle

Master's Theses

Longleaf pine (Pinus palustris Mill.) ecosystems are one of the most endangered and ecologically diverse systems in North America. The native herbaceous species serve as fuel for low-intensity, recurring fires this system relies on. The herbaceous species play major roles in maintaining ecosystem structure and diversity. Soil microorganisms like bacteria are known to aid greatly in many different plant and ecosystem processes. However, little is known about the dominant herbaceous species and soil bacterial compositions within montane longleaf pine ecosystems, especially before and after a prescribed fire. We completed a multiyear, seasonal analysis of the soil bacterial community in …

Factors Affecting California Grassland Biodiversity: Two Case Studies, Nora Bales

Master's Theses

Biodiversity loss over the last century has been significant and is projected to increase. Biodiversity loss is accelerating due to climate change and habitat loss and degradation. Biodiversity supports key ecosystem services including pollination services, climate regulation, and water filtration. Biodiversity conservation is a top priority for land managers and researchers, however many ecological studies with practical applications lack a thorough understanding of the soil environment in their study system. We conducted two case studies integrating soil and plant data to answer management questions. The first case study investigated the relationship between a threatened plant, Hooveria purpurea var. purpurea and …

Investigation Of Dead Ocean Quahogs (Arctica Islandica) Shells On The Mid-Atlantic Bight Continental Shelf, Alyssa Leclaire

Master's Theses

Ocean quahogs, Arctica islandica, are a long-lived, widely dispersed, biomass dominate in the Mid-Atlantic; therefore, quahog shells are valuable resources for studying climate change over time. Recently, dead ocean quahog shells were discovered south and inshore of the present biogeographic range of this animal. The presence of ocean quahog shells outside the current range is presumably a consequence of past regressions and transgressions of the Cold Pool, the bottom-trapped, cool body of water that allows boreal animals to live at lower latitudes. Dead ocean quahog shells were collected offshore of the DelMarVa Peninsula then radiocarbon-dated, evaluated for taphonomic condition, …

Population Genetics Of Cownose Rays, Rhinoptera Spp. In The Western Atlantic, Helen Weber

Master's Theses

Using molecular tools (e.g., the NADH subunit II mitochondrial gene), this study was the first to document the Brazilian cownose ray, Rhinoptera brasiliensis, within the northwestern Atlantic (NWA), and was the first study to examine population structure in R. brasiliensis within the NWA or northern Gulf of Mexico (GMX), revealing novel insights into the population biology of the animal and extending its range by nearly 1,500 km. This study also examined the sympatrically occurring American cownose ray, R. bonasus, and found population structure between the NWA and the GMX and the NWA and the southwestern Atlantic (SWA). High …

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 …

Selection Of Overwintering Microclimate By Migratory Western Monarch Butterflies, Kiana Saniee

Master's Theses

Migratory species are expected to demonstrate habitat selection that occurs at multiple spatial and temporal scales. Western monarch butterflies migrate seasonally to overwinter in groves at geographically predictable locations along the California coast. To date, overwintering habitat selection by western monarch butterflies has been studied assuming that habitat selection occurs where overwintering aggregations form, meaning at the spatial scale where monarchs form dense overwintering aggregations within overwintering groves. We argue that since western monarch butterflies are migratory, studies of habitat selection could have commingled selection at different scales into a single spatial scale. This likely leads to ignoring some levels …

Habitat Heterogeneity Affects The Thermal Ecology Of The Federally Endangered Blunt-Nosed Leopard Lizard, Nicole Gaudenti

Master's Theses

Global climate change is already contributing to the extirpation of numerous species worldwide, and sensitive species will continue to face challenges associated with rising temperatures throughout this century and beyond. It is especially important to evaluate the thermal ecology of endangered ectotherm species now so that mitigation measures can be taken as early as possible. A recent study of the thermal ecology of the federally endangered Blunt-Nosed Leopard Lizard (Gambelia sila) suggested that they face major activity restrictions due to thermal constraints in their desert habitat, but that large shade-providing shrubs act as thermal buffers to allow them …

Testing The Climatic Variability Hypothesis With Coastal And Inland Populations Of Mimulus Guttatus And Implications For These Populations Under Climate Change, Alec Chiono

Master's Theses

How climate shapes the niche of a species is a core interest in evolution and ecology. Research on the evolution of climatic niches can inform us on the historical relationship between organisms and their climate, and, in an era of great environmental change, what that relationship may look like in the future. In this study, I tested an essential idea in the history of climate niche research, the Climatic Variability Hypothesis, by comparing the thermal niche breadth of coastal and inland populations of Mimulus guttatus. Using thermal performance results from this experiment, I also forecasted how the suitability of …

Assessment Of Genetic Diversity In Largetooth Sawfish, Pristis Pristis, Populations Over The 20th Century, Ann Fearing

Master's Theses

The Critically Endangered Largetooth Sawfish, Pristis pristis, experienced global declines in range and abundance over the past century and Australia is now their last stronghold. This research aimed to understand whether these declines have been accompanied by a reduction in levels of genetic diversity. Using P. pristis tissue samples sourced from natural history specimens, three fragments (616-bp, 386-bp, 141-bp) in the mitochondrial DNA (mtDNA) control region were PCR-amplified. At each fragment, significant genetic structure was found in P. pristis overall (Φ_ST=0.946, N=9; 0.813, N=54; 0.771, N=99). The Indo-West Pacific and Atlantic/Eastern Pacific each harbor genetically distinct lineages of …

Pismo Clams (Tivela Stultorum) In Califorina: Population Status, Habitat Associations, Reproduction, And Growth, Alexandria R. Marquardt

Master's Theses

Marine shellfish play a vital role in intertidal ecosystems and coastal communities, but many of these fisheries are small-scale and lack the necessary monitoring to ensure long-term sustainability. Effective management often requires information on key demographic parameters, such as population status, reproduction and growth. Pismo clams (Tivela stultorum) are a culturally important and iconic species in California, which supported a thriving commercial and recreational fishery throughout much of the 1900’s. However, Pismo clam populations have declined statewide in recent decades and are attributed to human harvest and predation by California sea otters (Enhydra lutris); However, no …

Short Term Shifts In Soil Nematode Food Feb Structure And Nutrient Cycling Following Sustainable Soil Management In A California Vineyard, Holly M. Deniston-Sheets

Master's Theses

Evaluating soil health using bioindicator organisms has been suggested as a method of analyzing the long-term sustainability of agricultural management practices. The main objective of this study was to determine the effects of vineyard management strategies on soil food web structure and function, using nematodes as bioindicators by calculating established nematode ecological indices. Three field trials were conducted in a commercial Pinot Noir vineyard in San Luis Obispo, California; the effects of (i) fertilizer type (organic and inorganic), (ii) weed management (herbicide and tillage), and (iii) cover crops (high or low water requirements) on nematode community structure, soil nutrient content, …

Life-History Characteristics And Fishery Dynamics Of Red Drum (Sciaenops Ocellatus), In The North-Central Gulf Of Mexico, Corbin Bennetts

Master's Theses

Red Drum (Sciaenops ocellatus) are highly targeted recreationally in the Gulf of Mexico, and support a small commercial fishery in Mississippi. Despite their popularity, the stock is assessed using data limited approaches that necessitate accurate life history information. I estimated the year-specific and year-aggregated escapement rates for the Mississippi stock (years 2004 to 2015), which were sensitive to mortality estimation methods; year-aggregated estimates were 6.9 to 28.2 % depending on the method, but temporal patterns were consistent. I then addressed concerns with previously estimated life-history characteristics by describing the sex-specific growth and reproductive dynamics. The three-parameter von Bertalanffy …

Environmentally-Driven Variation In The Population Dynamics Of Gulf Menhaden (Brevoortia Patronus), Grant D. Adams

Master's Theses

Gulf Menhaden (Brevoortia patronus) is an abundant forage fish distributed throughout the Northern Gulf of Mexico (NGOM). Gulf Menhaden support the second largest fishery, by weight, in the United States and represent a key linkage between upper and lower trophic levels. Variation in the population dynamics can, therefore, pose consequences for the ecology and economy in the NGOM. Here we aim to understand variation in the individual and population dynamics of Gulf Menhaden throughout ontogeny and how such variation relates to environmental processes. We utilized a suite of fishery-dependent and –independent, remote sensing, modeled, and in situ data …

Evidence Of Multidecadal Recruitment In The Ocean Quahog, Arctica Islandica In The Western Atlantic Ocean, Sara M. Pace

Master's Theses

Ocean quahogs (Arctica islandica) are the longest-lived, non-colonial animals known today, with a maximum life span exceeding 500 years. Limited information is available regarding recruitment, making the sustainable management of this valuable fishery a challenge. The objective of this research was to describe the age structure and growth rates for four populations of ocean quahogs from the mid-Atlantic stock to evaluate long-term recruitment trends. Clams were sectioned for age estimation to develop population age frequencies. Initial colonization began approximately 175-250 years ago depending upon site. All sites experienced an increase in recruitment beginning in the late 1800’s to …

The Population Genetics Of Morro Bay Eelgrass (Zostera Marina), Julia Gardner Harencar

Master's Theses

Seagrass populations are in decline worldwide. Zostera marina (eelgrass), one of California’s native seagrasses, is no exception to this trend. In the last 8 years, Morro Bay, California has lost 95% of its eelgrass. Eelgrass is an ecosystem engineer, providing important ecosystem services such as sediment stabilization, nutrient cycling, and nursery habitats for fish. The failure of recent restoration efforts necessitates a better understanding of the causes of eelgrass decline in this estuary. Previous research on eelgrass in California has demonstrated a link between population genetic diversity and eelgrass bed health, ecosystem functioning, and resilience to disturbance and extreme climatic …

An Assessment Of Potential False Positive E.Coli Pyroprints In The Cplop Database, Skyler A. Gordon

Master's Theses

The genetic information found in each species of organism is unique, and can be used as a tool to differentiate at the molecular level. This has caused rapid genotyping methods to become the cornerstone of a new area of research dependent on reading the genome as a form of identification. One of these specific identification methods, known as pyroprinting, relies on the small variation of DNA sequences within the same species to develop a unique, reproducible fingerprint. By simultaneously pyrosequencing multiple polymorphic loci within the ribosomal operons known as the intergenic transcribed spacers, a reproducible output is obtained, known as …

Development Of Genomic Resources For The Evaluation Of Red Snapper, An Emerging Species Candidate For Marine Aquaculture And Stock Enhancement, Adrienne Elise Norrell

Master's Theses

The northern red snapper (Lutjanus campechanus) is a highly targeted reef fish candidate for marine aquaculture and stock enhancement in the southern United States. This work aimed to develop genomic resources for the genetic management of aquaculture programs and to investigate population structure using high-throughput sequencing technologies. Eighty-four new microsatellite markers were developed through screening of Illumina paired-end sequencing reads. Microsatellite loci and Single Nucleotide Polymorphisms (SNPs) generated through Restriction Site Associated DNA (RAD) sequencing were assayed in 5 outbred full-sib families to construct a high-density linkage map of the red snapper genome. The map consists of 7,964 …

The Effectiveness Of Periodically-Harvested Closures In Meeting Ecological And Socioeconomic Objectives, Paul G. Carvalho

Master's Theses

Periodically-harvested fisheries closures (PHCs) are a widespread form of community-based marine spatial management used throughout the Indo-Pacific that also is currently being intensively advocated by conservation organizations for supporting productive fisheries and healthy marine ecosystems. However, local implementation of PHCs has historically been designed to support occasional and efficient exploitation of fish stocks, and not necessarily sustainable fisheries yields and stock conservation. The efficacy of PHCs for achieving their historical cultural objectives of periodicity and efficiency of harvest, simultaneously with achieving contemporary fisheries objectives of fisheries productivity and conservation is undetermined. As a result, the utility of PHCs for supporting …

Fishery And Population Dynamics Of Mississippi’S Spotted Seatrout, David Arthur Dippold

Master's Theses

Spotted Seatrout (Cynoscion nebulosus) is the most popular recreational inshore fishery in Mississippi coastal waters. Because of the popularity of Spotted Seatrout in Mississippi as a recreational target and the magnitude of harvest, quantitative approaches to describe the population and fishery dynamics of the Mississippi stock are needed to continue the sustainability of the stock. Quantitative approaches to describing stock dynamics are useful because they can help describe population characteristics, assess the current status of the stock, and be used to evaluate alternative management strategies. In this thesis, I use a suite of quantitative methods to describe, evaluate, …

The Conservation Genetics Of Two Emydid Turtles: Emydoidea Blandingii And Malaclemys Terrapin, Charlotte Lizana Petre

Master's Theses

Conservation of turtles is complicated by their sensitivity to habitat degradation and overexploitation. I used microsatellites and standard population genetic analyses to explore genetic diversity, population structure, paternity and demographic history in two emydid turtles that are currently experiencing threats to their survival. The Blanding’s turtle, Emydoidea blandingii, has experienced habitat fragmentation throughout its range, and this study focuses on a population in Massachusetts where hatchlings from one population are being translocated to establish a new population. I found evidence of multiple paternity within clutches and found no significant reduction in genetic diversity when comparing the source population and …

Spatial And Temporal Comparisons Of Gopher Rockfish (Sebastes Carnatus) Life History And Condition In South Central California, Natasha Leigh Meyers-Cherry

Master's Theses

Recent studies have shown environmental factors influence life history traits in fishes. Understanding intraspecific variability of life history characteristics and condition is necessary to determine local fisheries management strategies. Gopher rockfish, Sebastes carnatus, comprise 50% of the estimated shallow nearshore recreational rockfish catch in California, yet insufficient local data exist regarding life history traits and condition of this species. Our study locally defines growth parameters (maximum size and age), size (age) at reproductive maturity, and condition (hepatosomatic indices) for gopher rockfish in south central California. The growth parameter values of gopher rockfish from our study are similar to previously …

Monarch Butterfly (Danaus Plexippus) Tree Preference And Intersite Movement At California Overwintering Sites, Jessica Lynn Griffiths

Master's Theses

Managing Monarch butterfly overwintering groves: making room among the eucalyptus

Proper management and conservation of the coastal California overwintering sites used by western Monarch butterflies (Danaus plexippus L.) is critical for continued use of these sites by monarchs. Many management efforts are currently concentrating on eucalyptus-only sites because of the prevailing notion that monarchs prefer eucalyptus over native tree species. Yet, whether a preference exists or not has never been tested. Herein, we test the “eucalyptus preference” hypothesis with data from five overwintering sites comprised of blue gum eucalyptus (Eucalyptus globulus) and at least one other native tree …

An Assessment Of Habitat Suitability For Pronghorn Populations Of The Central Valley Region Of California, Virginia Burroughs

Master's Theses

Efforts to reintroduce and maintain populations of pronghorn (Antilocapra americana) to the California Central Valley, specifically the Carrizo Plain National Monument (CPNM) and the Mojave Desert (Antelope Valley) portion of Tejon Ranch, have largely been unsuccessful due to dwindling numbers of translocated animals. The objective of this study was to improve upon previous models for the CPNM using aerial survey data and then apply the model to the Tejon Ranch. Aerial survey data collected from 2000-2010 on the CPNM was used to establish “use” and “non-use” areas in the model. Model variables included vegetation type (forest, shrub, grassland, …