Population Biology Commons^™

Teeth That Tell Time: Elemental Analysis From Shark Teeth, Gisele-Elizabeth Perez

Posters - 2026

Sharks (Chondrichthyes) have hunted in the oceans for over 400 million years, their teeth leaving history behind, constantly becoming a part of the fossilization process (Worm et al. 2013). Their survival throughout 5 major extinctions is due to their ability to adapt easily with slow metabolism, a wide range of diet, and an efficient physiology. Shark teeth are vital to the hunting and consumption of their prey, making it a point for scientists to study them. Their tooth minerals contain fluorapatite in their enameloid, and dentin in the “root” of the tooth, with extinct species containing dentin and hydroxyapatite in …

The Missing Lynx: Ivestigating Passive And Active Rewilding With The Eurasian Lynx, Isaiah Charles, Tatiana Flores, Isabella Lopez

Posters - 2026

The Eurasian Lynx (Lynx lynx) is a wild cat native to the boreal forests, mountains and grasslands of Europe and Asia (Bhattacharyya, 2025). The Eurasian lynx keep ungulate populations in check which allow for forests to recover from overgrazing, promoting biodiversity and ecological balance. However, the Eurasian lynx had become locally extinct across Europe by the 1900s due to habitat loss, hunting by farmers in retaliation for predation of livestock and the illegal fur trade. Conservation and ecological restoration efforts to rebuild the lynx population have been underway. Rewilding is a form of ecological restoration involving the reintroduction of a …

Emerald Bowfin Amia Ocellicauda Ecology In Three Minnesota Lakes: Abundance, Age Analysis, Diet Composition, And Stable Isotope Food Web, Griffin Blegen

Biology Graduate Theses

The Emerald Bowfin Amia ocellicauda is a predatory fish species native to Minnesota that has often been discriminated against. This research expands ecological knowledge of Bowfin in Minnesota and provides population data to guide future management. Bowfin were sampled in the spring of 2024 and 2025 and a multi-census mark–recapture model was used to estimate abundance in three lakes. Estimated populations were 196 individuals in Little Toad Lake (95% CI: 116, 242) or 4.4 fish/littoral ha (95% CI: 2.7,5.7), 657 in Lake Sarah (95% CI: 436, 1014) or 4.2 fish/littoral ha (95% CI: 3.0, 6.7), and 612 in Gun Lake …

Optimal Control And Bifurcation Analysis Of A Predator–Prey Model With Self-Limiting Growth And Predator Disease, Dipo Aldila, Muhammad Akmal Fasya, Bevina D. Handari, Chidozie Williams Chukwu, Olumuyiwa James Peter

Mathematical Modelling and Numerical Simulation with Applications

We propose and analyze an eco-epidemiological predator–prey model that incorporates self-limitation and disease transmission within the predator population. The model is formulated as a system of ordinary differential equations describing logistic prey growth under the interspecific interaction with the predator. On the other hand, the predator population is divided into susceptible and infected classes, whose growth is constrained by prey availability. Three biologically relevant equilibria are identified: predator extinction, disease-free coexistence, and coexistence with endemic disease. The existence and stability of these equilibria are determined by key ecological and epidemiological thresholds, including the basic reproduction number. Using numerical continuation methods, …

Optimal Control Strategies For Infectious Diseases: A Numerical Simulation Approach, M. Abu Salek, Jannatun Nayeem, Romana Yesmin, M. Haider Ali Biswas, M. Humayun Kabir

Mathematical Modelling and Numerical Simulation with Applications

Various infectious diseases, such as Tuberculosis and Hepatitis B virus (HBV), caused by Mycobacterium bacteria and hepatitis B virus, respectively, pose serious threats worldwide. This paper examines the spread of these diseases using a mathematical model that incorporates control measures, including vaccination and awareness programs. We use a system of differential equations with control variables and apply Pontryagin's principle to determine optimal control strategies. The stability of the Disease Free Equilibrium (DFE) has been analysed and demonstrated to be both locally and globally asymptotically stable when the basic reproduction number remains below unity, thereby ensuring disease elimination. Furthermore, the Endemic …

Dynamical Analysis And Optimal Control Of The Mpox Transmission Model With Stratified Susceptibility, Tuhfatul Janan, Fatmawati Fatmawati, Cicik Alfiniyah, Santi Martini, Dipo Aldila, Agus Hasan

Mathematical Modelling and Numerical Simulation with Applications

This study develops a mathematical model of Mpox transmission that combines stratified susceptibility (low-risk and high-risk groups) with vaccinated and asymptomatically infected compartments. The analysis of the model begins with examining the well-posedness, boundedness, and nonnegativity conditions for the solutions. The local stabilities of the equilibria are examined through the Jacobian matrix and phase plane analysis, while the global stabilities are provided through Lyapunov functions. The estimated parameters are verified using epidemiological data on Mpox cases in the United States, with an MAPE of 2.20% and R_0 > 1, indicating that Mpox remains endemic. Sensitivity analysis indicates that the contact rate …

Louisiana Species Of The Genus Xestia Hübner And The Genus Agnorisma Lafontaine, Vernon Antoine Brou Jr., Charlotte Dozar Brou

The Taxonomic Report of the International Lepidoptera Survey

We address three species of the genus Xestia Hübner recorded for the state of Louisiana: Xestia dilucida (Morrison), Xestia elimata (Guenée) and Xestia c-nigrum (Linnaeus), and we also address new state capture records for Agnorisma badinodis (Grote) and Agnorisma bollii in Louisiana.

Three Butterfly Genera Across The Central Texas Suture Zone, Qian Cong, Jing Zhang, Jinhui Shen, Leina Song, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

Genome-scale analyses of butterfly specimens across the Central Texas Suture Zone revealed that several taxa currently treated as subspecies exhibit genomic differentiation similar to that observed between species. Further investigation and genomic sequencing of additional specimens from across the ranges of these taxa support this conclusion and result in the following changes to nomenclature and taxonomy. Two new subspecies of Nymphalidae Rafinesque, 1815 are described: Asterocampa louisa monterra Grishin, ssp. n. (type locality in Mexico: Nuevo León) and Asterocampa clyton plana Grishin, ssp. n. (type locality in USA: Texas, Denton Co.). The following taxa are recognized as species, not subspecies: …

(Si16-21) Dynamical Study Of A Hassell-Varley Model With Nonlinear Harvesting And Fear Effect In Prey, Aditya Bhattacharya, Anindita Bhattacharyya

Applications and Applied Mathematics: An International Journal (AAM)

In this article, a one predator-one prey model incorporating Richards’ type growth in prey population, Hassell-Varley type functional response and Michaelis-Menten type prey harvesting is proposed and analyzed. Richards’ type growth with fear factor is incorporated in the proposed model to generalize the reduction effect of predator-induced fear on the rate of growth of the prey population. Positivity and boundedness of the system’s solutions are first established to ensure biological feasibility of the model. Existence and stability conditions of various types of equilibrium points associated with the model such as trivial equilibrium, axial (predator–free) equilibrium and coexistence equilibrium are obtained …

Trophic Structure And Mercury Bioaccumulation In Walleye And Yellow Perch In The Upper And Lower Red Lake Basins, Marissa Pribyl

Biology Graduate Theses

Mercury is a persistent global contaminant that biomagnifies through aquatic food webs, with dietary and environmental factors serving as the primary drivers of accumulation in fishes. Trophic structure and methylmercury dynamics in Walleye (ogaa; Sander vitreus) and Yellow Perch (asaawens; Perca flavescens) were investigated in the Upper and Lower Red Lake basins in Red Lake, Minnesota, during 2024-2025. Diets of Walleye and Yellow Perch were assessed through stomach dissections, and tissue samples from both species were analyzed for total mercury concentrations. Additional analyses included shiners (gigoozens; Notropis spp., Hudsonius spp.) along with a variety of freshwater fish and …

Observations Of Puddling Butterflies In Maryland, Usa, Aydin Örstan

The Taxonomic Report of the International Lepidoptera Survey

Six butterfly species in four families were observed puddling on damp soil, scat and carrion in various locations in Montgomery County, Maryland and on small islands in the Potomac River. Four species preferred damp soil to nearby mud, but the reason for this behavior is unknown. The presence of butterflies on small islands in the Potomac River is documented for the first time.

A Taxonomic Overview Of The Apodemia Mormo Complex From A Genomic Perspective, Jing Zhang, Qian Cong, Jinhui Shen, Leina Song, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

Genomic analysis of the Apodemia mormo group (Riodinidae Grote, 1895 (1827)) specimens across the range from southwestern Canada through much of the western USA and northwestern Mexico, complemented by phenotypic examination and photographs of live individuals to inspect eye color, partitions the complex into eight species, one of which is proposed as new: Apodemia (Apodemia) apache Grishin, sp. n. (type locality in USA: Arizona, Apache Co.), and three elevated from subspecies of A. mejicanus: Apodemia (Apodemia) maxima (Weeks, 1891), stat. rest., Apodemia (Apodemia) deserti W. Barnes & McDunnough, 1918, stat. nov., and Apodemia ( …

Vultures, Bryan M. Kluever, Lee A. Humberg, Scott C. Barras

Wildlife Damage Management Technical Series

Fact sheet about vultures including information about human--wildlife conflicts, the vulture roost, affects on livestock, structures, human health and safety, identification of damage, management methods, legal considerations, and economics. Also included is an overview of the species.

Reproductive Biology Of Hybopsis Amblops, The Bigeye Chub, In The Flint River Of Alabama, Crissy L. Tarver, Bruce W. Stallsmith

Southeastern Fishes Council Proceedings

The purpose of this study was to establish a reproductive schedule and examine reproductive traits that shape fecundity of the Bigeye Chub, Hybopsis amblops Leuciscidae in the Flint River system of north Alabama. Traits associated with reproduction, growth, and maturation were assessed. Specimens were collected and examined monthly from August, 2013 until July, 2014. This Bigeye Chub population primarily spawns in April and May as indicated by gonadosomatic index (GSI), ovarian condition and clutch size. Mean GSI values began to rise in February, peaking in April and May at over 13% for females and 1.6% for males. There was a …

Decoupling Of Reproduction And Lifespan Trade-Off In Caenorhabditis Elegans Through Microbial Programming, Nora M. Villafuerte

LSU Master's Theses

The microbiome is increasingly recognized as a major regulator of host physiology. Using the Caenorhabditis elegans model, we investigated how natural commensal bacteria modulate host reproduction and lifespan through internal egg hatching, a phenotype in which retained embryos hatch within the maternal body. Screening strains from the CeMbio collection identified four focal strains Ochrobactrum BH3, Lelliottia JUb66, Pantoea BIGb0393, and Enterobacter CEent1 that significantly increased internal egg hatching during the late reproductive period. This contrasts with pathogenic bacteria, which induce early-onset internal egg hatching. Across the focal strains, worms exhibited reduced total brood size but an expanded reproductive window relative …

Assessing Localized Recovery And Synchrony Of An Endangered Wetland Species., Aiyana Reissman

Theses

The state and federally endangered light-footed Ridgway’s rail (LFRR; Rallus obsoletus levipes) is central to regional conservation, yet the drivers of its population fluctuations remain poorly understood. The fragmented nature of coastal wetlands in Southern California is threatening the existence of endemic species like the LFRR. Tidal inundation, severe storms, and overpredation threaten the survival of LFRR. This study addresses population fluctuations by analyzing the spatial and temporal drivers of LFRR populations to inform effective, site-specific management.

To do this, a 45-year (1980–2024) LFRR census data set across 16 wetlands throughout its range in California was synthesized. A multi-faceted …

Relationship Between Ratio Of Hybrid Sunfish To Their Parent Species And Latitude, Maxwell Kattner

Journal of Earth and Life Science

Hybrid sunfish of the Lepomis genus make up a generally small but notable portion of the population of sunfish in Minnesota lakes. Hybrid sunfish play a significant role in freshwater ecosystems across the United States. They are both morphologically and behaviorally distinct in some ways and similar in other ways to their parent species, causing them to both fill and compete with their parent species for niches occupied by multiple Lepomis species. Despite this, the ratio of hybrid sunfish to their parent species has never been properly explored. This study observed if the ratio of hybrid sunfish to their parent …

Coho Salmon (Oncorhynchus Kisutch) Response To Habitat Restoration Through Space And Time: Monitoring Growth, Survival, And Movement In A Restored Habitat Network, Carter Perez Adamson

Cal Poly Humboldt theses and projects

Despite the decline of coho salmon (Oncorhynchus kisutch), Prairie Creek, a tributary of Redwood Creek in northern California, remains a coho salmon stronghold. The restoration of juvenile coho rearing habitat was identified as a recovery objective in this watershed by the National Marine Fisheries Service. Among the restoration projects addressing this objective are an ongoing project on Prairie Creek and its tributary Skunk Cabbage Creek, and a prior effort on Strawberry Creek (a tributary of Redwood Creek’s estuary). Standard monitoring methods for assessing project success have limitations and may be improved by measuring salmon use of restored habitats …

Geographic Variation In Proteomic Responses To Ocean Acidification In A Cold-Water Coral (Balanophyllia Elegans), Keana A. Richmond

Cal Poly Humboldt theses and projects

In the face of a rapidly changing climate, assessing organismal responses to future stressors in the context of current, natural exposure to stress could provide key insights to understanding marine ecosystem resilience. I used Balanophyllia elegans, a cold-water, solitary, azooxanthellate coral as a model to better understand how varying oceanographic conditions across its geographic range have shaped its ability to tolerate and potentially adapt to current and future ocean acidification conditions. I collected B. elegans individuals from four sites across 2,500km of their range and subjected them to two pH treatments to investigate site-specific protein expression in response to …

Impacts Of Native And Nonnative Plant Species On Avian Community Diversity, Matty John Mackay, Steven Van Dang, Brandon Lee Corn

SPARK Symposium Presentations

Avian communities play an essential role in maintaining a healthy ecosystem dynamic by regulating insect populations, assisting in plant pollination, and seed dispersal. These contribute to the overall health of natural ecosystems and mitigate ecological disruptions that would arise in their absence. However, the introduction of non-native invasive plant species can interrupt the balance avian communities bring to ecosystems by reducing availability of food sources, altering habitat structures, increasing competition among individuals, and disrupting ecological relationships through rapid invasion of ecological spaces. Point count observations of birds at Shelby Bottoms Park, Nashville, Tennessee in areas dominated by non-native privet and …

A Frog, A Toad, And A Salamander Walk Into A Forest: How Timber Harvest And Environmental Conditions Impact Amphibian Species Abundance In The White Mountain National Forest, William T. Brandenburg

Honors Theses and Capstones

Balancing the needs of humans and wildlife is one of the primary goals of conservation. Understanding how species respond to resource extraction is essential to achieve long-term population stability. This is especially relevant for amphibians, which are particularly sensitive to environmental disturbances due to habitat loss and degradation. As such they are often used as indicator species. This study leverages 20-years of amphibian abundance data from surveys in different silvicultural treatments to understand how American toads (Anaxyrus americanus), wood frogs (Lithobates sylvaticus), and red-backed salamanders (Plethodon cinereus) respond to changes in forest structure, weather, …

Current And Historical Occurrences Of Rare Coastal Plants In The Hampton Falls Salt Marshes, Liliana T. Chirichella

Honors Theses and Capstones

A botanical survey of two sites in the Hampton Falls saltmarshes was conducted to document the occurrences of a list of eleven endangered and threatened coastal plants listed in the Natural Heritage Bureau’s NH Rare Plant List. This survey was conducted in fulfillment of the NH Native Plant Protection Act to highlight and identify target species in an area where restorative runneling is to be implemented in order to restore proper hydrology and prevent further expansion of mega-pools in the Little River and Depot Road salt marsh sites, which have been subject to historical ditching and are a part of …

Hidden In The Mist: Three New Species Of Salamanders Of The Genus Pseudoeurycea (Amphibia: Plethodontidae) From Oaxaca, Mexico, Eduardo A. Aguilar-Herrera, Salomón Sanabria-Urbán, Dulce L. Flores-Martínez, José David Gómez-Tapia, Misael Seba-Chacha, Leopoldo D. Vázquez-Reyes, Francisco A. Rivera-Ortíz, Patricia Ramírez-Bastida, Bruno Cortés-Ortiz, R. Alejandro Calzada-Arciniega, Etienne U. Avila-Ortega, Dónovan I. Víquez-Vega, Omar Hernández-Ordoñez, Christopher Blair, Víctor H. Jiménez-Arcos

Publications and Research

We describe three new species of lungless salamanders (Plethodontidae) in the genus Pseudoeurycea from Cerro Rabon, located on the eastern slopes of the Sierra Mazateca, Oaxaca, Mexico. This mid-elevation mountain, largely surrounded by warmer lowlands, remains relatively understudied. We present molecular and morphological evidence distinguishing the three new species from their congeners. According to our phylogenetic analysis, one of the new species belongs to the P. leprosa group, while the other two are members of the P. juarezi group. Notably, one of the new species represents the fourth worm salamander known from west of the Isthmus of Tehuantepec, and another …

Fisheries Research Report No. 359: Metropolitan Monitoring Program 2025, Alissa Tate, Claire B. Smallwood, Karina L. Ryan, Troy Matthews

Fisheries Research Reports

Ongoing monitoring of recreational fisheries in the Perth Metropolitan zone is essential to ensure the sustainable use of fisheries resources. Surveys of shore- and boatbased recreational fishers within the Metropolitan zone of the West Coast bioregion provide information on human dimensions and catch-per-fisher as well as mean length and weight of key recreationally caught species. For shore-based fishers, estimates of fishing effort, catch and harvest are also presented for key nearshore species. This information is used to support ongoing assessments for key nearshore species and the development and evaluation of harvest strategies and other management actions, such as for Australian …

Managing Multi-Drug Resistance: An Evolutionary Game Theory And Optimal Control Approach, Shukhrat Nasrulloev

Theses and Dissertations

Multi-drug resistance is an evolutionary process in which treatment eliminates sensitive cells, allowing resistant clones to dominate. This thesis investigates this process using a framework integrating population dynamics, evolutionary game theory, and optimal control theory. We develop a two-population logistic growth model describing competition between drug-sensitive and drug-resistant cells under treatment, construct dose-dependent payoff matrices and replicator dynamics to characterize evolutionary competition, and derive a critical drug level D_crit = (r_S - rR)/(dS - d_R) at which resistant cells gain a fitness advantage. An optimal control problem is formulated via Pontryagin's Maximum Principle to identify schedules …

Mapping The Distribution Of The Common House Mosquito (Culex Pipiens) In The City Of Spokane: Mosquito Breeding Sites And Blood Meal Analysis, Oluwapelumi Hannah Sonoiki

EWU Masters Thesis Collection

Mosquitoes in the genus Culex are the primary vectors of West Nile virus (WNv) in the United States, with Culex pipiens and Culex tarsalis serving as the dominant species in Spokane. In urban environments, catch basins and other artificial water bodies that collect stagnant and polluted water provide favorable breeding habitats for Culex pipiens. This study aimed to assess the spatial distribution and seasonal dynamics of Culex larvae in Spokane. We examined 303 randomly selected catch basins in the summer of 2025, and at each site we recorded the presence or absence of water, water depth, and mosquito larval …

False-Positive Detections In Avian Auditory Surveys: Effects Of Song Number And Directionality In A Calibration-Based Immersive Sound Environment, Katia Elena Chavez

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Detection-based surveys are widely conducted to monitor wildlife populations and provide data for estimating density and abundance. Avian count surveys are especially common because birds respond quickly to habitat degradation and restoration, making them effective indicator species. However, these detection-based surveys rely heavily on human observers and are prone to errors. If left unaddressed, these errors can bias estimates of species occurrence, and abundance, leading to misleading ecological inferences and management decisions. False-positive errors have received limited attention, in part because they are difficult to identify without independent confirmation of true species. To investigate false-positive rates in a controlled setting, …

Long-Term Banding And Encounter Patterns Of Cinnamon Teal Banded In Utah (1960-2025), Gracie A. Henrie

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Utah is a valuable breeding and nesting ground for a number of waterfowl species, largely because of the Great Salt Lake, which supports over 400,000 acres of wetland habitat (Ducks Unlimited, n.d.). The Utah Division of Wildlife Resources manages 24 wildlife management areas (WMAs) with the purpose of creating high quality waterfowl habitat in these wetlands that can be enjoyed by hunters, recreators, and birds alike (Wildlife/Waterfowl Management Areas (WMAs), 2025). Effective management is supported with an understanding of the movement and demographic patterns of the waterfowl species the WMAs are designed to support. Bird banding is one tool managers …

Equid Major Histocompatibility Complex (Mhc) Evolution & Genome Organization, Lauren C. Johnson

Theses and Dissertations--Veterinary Science

The evolution of modern horses has a well-documented fossil record and has long been of interest to the genetics community. Although non-caballine equids (e.g. zebras, donkeys, and asses) can hybridize with horses, the resulting offspring are typically infertile. Despite these reproductive barriers, genomic analyses reveal regions of high sequence similarity among equid species. This dissertation investigates the role of historical introgression in the evolution of modern Equus species. The first chapter re-evaluates earlier findings derived from a limited horse population and a single reference genome. The variants of the identified regions were pushed through Ensembl’s Variant Effect Predictor to assess …

Using Camera-Based Unmarked Spatial Capture-Recapture Modeling To Estimate Reintroduced Elk (Cervus Canadensis) Population Parameters And Distribution In Southeastern Kentucky, Claire Marie Muia

Theses and Dissertations--Forestry and Natural Resources

Estimation of population parameters is important for wildlife management decisions. Elk reintroduced to southeastern Kentucky experienced early irruptive population growth and are currently monitored using a statewide harvest-based statistical population reconstruction model (SPR) across the Kentucky Elk Restoration Zone (KERZ). Because the SPR model is spatially coarse and difficult to scale to the smaller management units comprising the KERZ, we conducted a spatially explicit capture-recapture study using a clustered camera-trapping array deployed for 10 weeks from June–August 2024 to estimate elk population parameters within Management Unit 4. Due to a lack of resights of GPS-marked elk, population parameters were estimated …