Population Biology Commons^™

Bearpaw Reserve Wildlife Monitoring And Mapping With The Wildlands Conservancy, Hope Hansen

Scripps Senior Theses

For my Environmental Analysis Capstone, I worked in a small group to monitor and map the wildlife at Bearpaw Reserve. Bearpaw Reserve, located in Forest Falls, California, is a 600 acre tract of wilderness that is owned by The Wildlands Conservancy. Bearpaw is located about an hour from Claremont, in the San Bernardino Mountains. The Wildlands Conservancy makes management decisions about its reserves while applying conservation research to the real world.

My group’s task was to use trail cameras to gather data on the wildlife at Bearpaw, then visualize this information into a GIS map. We used a combination of …

Sediment Redox-Driven Iron Flux And Phytoplankton Community Responses: Implications For Cyanobacterial Suppression And Functional Stability Across Boreal Lakes, Julia K. Kozak

Theses and Dissertations (Comprehensive)

Freshwater eutrophication contributes towards the development of cyanobacterial harmful algal blooms (cHABs), but nutrient availability alone does not fully explain variation in phytoplankton community composition or physiological performance. While phosphorus (P) availability has been known to regulate phytoplanktonic biomass, iron (Fe) is an important micronutrient supporting Fe-heavy processes within cyanobacteria (i.e., nitrogen fixation and photosynthetic electron transport). Sediment Fe availability in freshwater ecosystems is regulated by reduction oxidation (redox) conditions at the sediment-water interface (SWI), where nitrate (NO₃^-) has been found to maintain oxidizing conditions and prevent the reduction of Fe(III) to more readily bioavailable soluble Fe(II), …

Phenotypic Variation Between Surface And Cave-Adapted Poeciliids And Its Effect On Metabolism, Karch Knipp, Michael Tobler, Soren Johnson

Undergraduate Research Symposium

Cave-adapted organisms often exhibit pronounced morphological changes relative to their surface counterparts, a phenomenon known as troglomorphy. In Poecilia mexicana (Atlantic molly), these differences include variation in coloration between surface and cave populations. Troglobitic organisms also typically exhibit reduced metabolic rates, likely as an adaptation to environments with low primary productivity. This makes P. mexicana an ideal system for investigating the evolution of metabolic traits. In this study, we leveraged variation in coloration among cave-dwelling mollies to examine potential associations with resting metabolic rate (RMR). Coloration was quantified using PCR values, and individuals were categorized as “yellow” or “non-yellow.” We …

Under The Surface: Human Disturbance Reduces Species Richness In Glade Microhabitats, Maddie Smith, Becky Hansis-O'Neill, Aimee Dunlap Phd

Undergraduate Research Symposium

Human disturbance can alter microhabitats in ways that affect biodiversity, especially in sensitive ecosystems like glades where many animals rely on rocks for thermoregulation and refuge. This study examined how rock displacement by human activity influences species richness and community composition in glade habitats at Shaw Nature Reserve and Victoria Glades Conservation Area. We hypothesized that disturbed rocks would be less suitable for wildlife and would support fewer species. From September to November 2025, about 30 rocks per site were pseudo-randomly selected and monitored. Each rock was classified as displaced or nondisplaced, and all organisms found beneath them were recorded. …

Bifurcation Dynamics Of A Harvested Predator-Prey Model, Hala H. Emam, Mohamed F. Abouelenein, Mona Anis, M. Y. Hamada, F. A. Atia, H. El-Metwally

Mathematical Modelling and Numerical Simulation with Applications

In ecosystems, the harvesting effect is essential to preserving the relationships between prey and predator. This work examines a model of predator-prey in discrete time with harvesting. The Jacobian matrix's eigenvalues are calculated for the associated fixed points. We examine the dynamical and qualitative analysis of this model, look into the criteria for stability and bifurcation, and analyze analytical results that show the rich dynamics and complexity of this model. We give sufficient circumstances for the Period-doubling at the interior equilibrium point by employing the harvesting effect. The discrete system's chaos control is carried out, and the outcomes are supported …

Distribution And Diversity Of Ponyfishes (Perciformes, Leiognathidae) In The Waters Of Sonmiani’S Bay, Balochistan, Pakistan, Noor Hawa, Noor Us Saher

Journal of Bioresource Management

The current research was conducted during October 2020 to September 2021 in bay waters of Sonmiani, Balochistan as aimed to fill the paucity of diversity and distribution of research for the bay waters. Monthly fish samples were collected using gill net and beach seine during high and low tide. In the present study, out of nine species, the six species were identified as a new report species belongs to Leiognathidae family. Secutor interruptus (N=132) was the most abundant species whereas the least abundant species collected during the study period was Karalla daura (N=1). Highest diversity (1.37) was estimated during the …

Differential Equation Modeling For Sustainable Resource Management: A Steady-State Optimal Harvesting Approach, Iordanka N. Panayotova, Aleksei Talonov

CODEE Journal

Mathematical models based on differential equations provide a powerful framework for connecting real-world data to informed decision-making. In this work, we present a student-accessible project that uses an optimal-control framework to study the sustainable management of biological resources.

Motivated by fisheries management, we examine a predator--prey system in which harvesting decisions must balance ecological and economic considerations. The model is formulated as an optimal control problem that seeks to maximize the total discounted net revenue from harvesting. Rather than solving for the complete time-dependent harvesting trajectory, we restrict the analysis to positive controlled coexistence equilibria and characterize an interior stationary …

Genomic Analysis Reveals New Subspecies Of Cercyonis Scudder, 1875 (Nymphalidae: Satyrinae: Satyrini), Jing Zhang, Qian Cong, Jinhui Shen, Leina Song, Todd L. Stout, Michael S. Fisher, Robb Hannawacker, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

Genomic analysis of Cercyonis (Cercyonis) Scudder, 1875 (Nymphalidae Rafinesque, 1815) partitions the subgenus into three species groups and reveals five new subspecies from the USA (type localities in parentheses): Cercyonis (Cercyonis) pegala koosharem Stout and Grishin, ssp. n. (Utah, Sevier Co.), Cercyonis (Cercyonis) pegala lasala Grishin, M. Fisher, and Hannawacker ssp. n. (Utah, Grand Co.), Cercyonis (Cercyonis) pegala hortoni Grishin, ssp. n. (Arizona, Gila Co.), Cercyonis (Cercyonis) meadii maculana Grishin, ssp. n. (Colorado, Montezuma Co.), and Cercyonis (Cercyonis) meadii rimana Grishin, ssp. n. (Arizona, Yavapai Co.). A neotype is designated for Satyrus boopis Behr, 1864 (USA, California, Contra Costa Co.). …

Modeling Population Growth With Logistic And Modified Logistic Equations, Mihil Dimpal Patel

Discovery Day - Daytona Beach

Population growth models are essential tools for understanding how biological populations change over time under environmental constraints. This study examines population dynamics by comparing the classical exponential growth model with the logistic growth model. While exponential growth assumes unlimited resources and results in unbounded population increase, the logistic model incorporates a carrying capacity that limits growth as resources become scarce. To better represent real-world conditions, the logistic model is extended by introducing modifications such as harvesting terms and time-varying carrying capacities, which account for external removal of individuals and changing environmental limits. The equilibria of these models are determined, and …

From Genes To Streams: Mitochondrial Approaches To Population Monitoring Of The Santa Ana Sucker Catostomus Santaanae, Mariana Antonio

Electronic Theses, Projects, and Dissertations

This study was developed to use aquatic environmental DNA (eDNA) as a tool to detect the presence of the Santa Ana sucker (Catostomus santaanae), a federally threatened fish species, across the Santa Ana River in Southern California. Environmental DNA is any genetic material that an organism sheds into the environment. We can get an idea of what aquatic species are present when sampling water at a given site. We sequenced the complete mitochondrial genome (mitogenome) of the Santa Ana sucker and designed custom DNA primers to improve eDNA detection accuracy. These primers were selected based on high genetic …

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 …

Influence Of Genetic Relationships On The Spatial Distribution Of Breeding Eastern Wild Turkeys (Meleagris Gallopavo Silvestris) In West-Central Louisiana, Rachel D. Price

LSU Master's Theses

Eastern wild turkeys (Meleagris gallopavo silvestris) have a complex social system influenced by dominance hierarchies and exhibit seasonal variation in gregarious behaviors. Previous work has examined the influence of kin relationships on interactions between same sex conspecifics and flock associations, but information on how genetic relatedness influences interactions between individuals remains lacking. We constructed a dyad-based social network using high-resolution GPS data from 179 female and 68 male wild turkeys in west-central Louisiana during the 28-day period before a females’ 1^st nest initiation to quantify interaction probability based on genetic relatedness and age. Our findings suggest that …

History And Distribution Of The Dark Ibises (Glossy Ibis Plegadis Falcinellus And White-Faced Ibis P. Chihi) In Arkansas, R. Tumlison, P. D. Rodriguez

Journal of the Arkansas Academy of Science

The Glossy Ibis (Plegadis falcinellus) and White-faced Ibis (P. chihi) sometimes are reported simply as Dark Ibises due to difficulty in identifying them when mature characters are not clearly visible. We evaluated reports verified on citizen science websites to examine the origins and distributions of these migratory species in Arkansas. The Glossy Ibis was first documented in Arkansas in 1956, has been reported in 21 of our 75 counties, and is found more commonly in eastern Arkansas. The White-faced Ibis was first reported in Arkansas in 1971, has been reported in 41 of our 75 counties, …

Butterfly Taxa Discovery Via Genomic Analysis, Jing Zhang, Qian Cong, Jinhui Shen, Leina Song, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

Expanding a genomics-guided assessment of butterfly taxonomy, we integrate phylogenetic evidence from all protein-coding genes with morphological considerations to refine our understanding of butterfly systematics and discover new taxa. As a result, 2 subgenera, 39 species, and 5 subspecies are proposed as new (type species in original combinations or type localities are listed in parentheses): Erebia (Magda) magdalena uintana Grishin, ssp. n. (USA: Utah, Uintah Co.) in Nymphalidae Rafinesque, 1815; Myselasia rondea Grishin, sp. n. (Brazil: Rondônia), Myselasia pseudocrinon Grishin, sp. n. (Ecuador: Pastaza), Myselasia paramatuta Grishin, sp. n. (Ecuador: Morona-Santiago), Euselasia anapellos Grishin, sp. n. (Peru: Loreto), …

Pickleweed In The Disappearing Marsh: Population Genetics & Metal Accumulation In Salicornia Depressa, Alice Kaisla

Graduate Doctoral Dissertations

Salicornia is a genus of succulent halophytes found in salt marshes around the world. Salicornia species have a remarkably high tolerance for heavy metal pollution and have been shown to accumulate high concentrations of heavy metals in their tissue under experimental conditions. As a result, they are both a useful system for studying evolution in polluted coastlines and a potential candidate for use in phytoremediation. My research focuses on Salicornia depressa, known as pickleweed, a species commonly found in marshes along the heavily urbanized and industrialized New England coast. I investigate genetic diversity and population structure in S. depressa populations …

Adapting Population Genetics, Practice, And Policy For Plant Conservation In A Changing World, Cooper M. Kimball-Rhines

Graduate Doctoral Dissertations

Biodiversity conservation is an inherently interdisciplinary goal that requires effective collaboration among academics, ecosystem managers, policymakers, and other stakeholders. Codesigning research with these groups ensures experiments are useful and improves adoption of policy and practice recommendations while advancing our understanding of basic science. This dissertation explores the power of codesigned research in shaping plant conservation strategies using stakeholder engagement, causal inference, demographic modeling, and multi-omic sequencing techniques. In chapter 1 I discuss the history of New England ecosystems and the need for research-driven changes to plant conservation policy and practice in the face of global change. In chapter 2, I …

Popgenhelpr: An R Package To Streamline And Facilitate Informed Population Genomic Analyses And Visualization Of Genetic Ancestry, Diversity And Differentiation, Keaka Farleigh, Mason O. Murphy, Christopher Marie Blair, Tereza Jezkova

Publications and Research

Analysing large population genomic datasets requires an interdisciplinary skillset. Beyond a knowledge base in genetics and population biology, population genomic analyses involve computer science and statistics, representing a barrier for researchers without experience in those fields. PopGenHelpR seeks to lower this barrier by enabling researchers to perform population genomic analyses and generate near-publication quality figures in a streamlined and informed fashion. PopGenHelpR allows users to estimate genetic diversity within populations as well as differentiation among populations and individuals from single nucleotide polymorphism data. PopGenHelpR includes commonly used measures such as observed heterozygosity and FST. PopGenHelpR also provides five …

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 …

Remote Sensing To Detect Crop Damage By An Invasive Species, Cole Butler

Biology and Medicine Through Mathematics Conference

No abstract provided.

Incorporating Thermal Performance Curves Into Population Dynamic Models For The West Nile Vector, Culex Pipiens, Benjamin Bruncati, Helle Aronson, Chloé Lahondère, Michael A. Robert

Biology and Medicine Through Mathematics Conference

No abstract provided.

Recognition Of The Spring Flight Of Celastrina (Tutt) (Lycaenidae: Polyommatinae) In Southern New England As An Introgressed Hybrid Species, Harry Pavulaan

The Taxonomic Report of the International Lepidoptera Survey

Populations of Celastrina (“Azure”) butterflies in southern New England have historically been referred to as either C. ladon (Cramer) or C. lucia (W. Kirby) by various authors. Following the discovery of elongated dorsal wing scales in males of C. ladon (D. Wright & Pavulaan, 1999; Ômura et al., 2015)—structures that replace the androconia that are typically present in most Celastrina species—it was believed that this trait was restricted to C. ladon, C. nigra (W. Forbes), and, more recently, C. iryna (Pavulaan, 2025). Microscopic examination of male “Spring Azure” specimens from across southern New …

Quantifying Genetic Diversity In Nematode Feeding Rate, Jacob King

Honors Theses

Understanding how populations persist under changing environmental conditions is a central question in ecology and evolutionary biology. Variation in traits related to resource acquisition may play a key role in determining population survival when resources are limited or fluctuate over time. In this study, I investigated how variation in feeding-related traits influences population persistence using a combination of computational modeling and laboratory experiments. I developed a stochastic, individual-based consumer–resource model to simulate population dynamics across varying levels of trait variance and resource regimes. Across 60,000 simulated populations, increased trait variation consistently reduced extinction risk and extended persistence time, although the …

A New Subspecies Of Papilio Indra (Papilionidae) From The West Desert Of Utah, Usa, Wayne H. Whaley, Alexander A. Jason, Todd L. Stout

The Taxonomic Report of the International Lepidoptera Survey

Papilio indra bonnevillensis is a new described subspecies partly based on taxonomic rearrangement of its larval host plant reproductive phenology relative to Wasatch Range nominate P. indra. It is geographically isolated in Utah’s West Desert from populations of ssp. nevadensis to the west and ssp. calcicola to the south. In addition to phenological differences compared to these two subspecies, it merits description based on host Lomatium depauperatum which recently speciated from L. grayi, neither of which is used as host by other subspecies of P. indra. The evolution of new host L. depauperatum is …

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 …

Contrasting Roles Of Downed Wood And Leaf Litter In Structuring Aphaenogaster Ants And Other Forest-Floor Arthropod Communities, Danielle E. Dolan

Great Lakes Center Masters Theses

Forest floors are dynamic and spatially heterogenous landscapes characterized by differing amounts of light, temperature, and moisture. Bounded substrates, like downed wood and leaf litter, add further complexity to this landscape. Specifically, downed wood is noted for its ability to retain a higher moisture level than the surrounding environment, and as such can serve as an ideal microhabitat for desiccation intolerant organisms (e.g., salamanders and eusocial insects). Here, I attempt to disentangle the relationship between forest floor arthropods and microhabitat selection (i.e., downed wood vs leaf litter) on a northeastern forest floor. The ant, Aphaenogaster picea, was chosen as my …

Enhancing Walleye (Ogaa) Recruitment: Evaluating Assisted Reproduction As A Mitigation Strategy, Douglass Keiser

Biology Graduate Theses

Over the past several decades, cold- and cool-water fish populations across the Upper Midwest, including Minnesota and Wisconsin, have shown troubling signs of decline. Among the most affected is the walleye/Ogaa (Sander vitreus), a species deeply embedded in the ecological balance, cultural identity, and economic vitality of the region, and central to the lifeways, treaty-reserved rights, and resource stewardship of Tribal Nations, including Ojibwe communities across the Upper Midwest. Despite ongoing stocking efforts and harvest regulations, many lake systems have experienced persistent declines in natural recruitment, prompting resource agencies to investigate the underlying causes. One such system is …

How Pollinator Populations Can Impact Chronic Disease Risk, Kylee Cubbison

Honors Projects

This project investigates how pollinator populations can impact chronic disease risk. Pollinator populations are declining, which can have serious implications for human health. Declining pollinator populations can limit healthy food production and affordability. Poor nutrition is a major risk factor for most chronic diseases. Less healthy food available for people to consume can negatively impact diets and increase the risk of developing chronic diseases. This project aims to address a potential gap in research existing on this specific topic regarding pollinator populations and human chronic disease risk. A brochure targeted towards educating the general public on this topic was created …

Skin Pattern As A Potential Monitoring Tool For Frog Populations, Lídize Sagarnaga Rivera, Virginie Rolland Dr., Lorin Neuman-Lee Dr.

Create@State

Skin pattern as a potential monitoring tool for frog populations

Population monitoring, which requires identifying individuals, is crucial for species conservation. Common techniques involve marking, which can harm animals and alter their behaviors. Natural markings are an alternative not yet explored for amphibians. Yet, the traditional method with elastomers (fluorescent implants) is invasive and not completely reliable—the tag may become lost or hard to see. The American green tree frog (Dryophytes cinereus) possesses naturally occurring and distinct golden dots on their dorsal side.  Therefore, we aim to assess whether patterns of golden dots on the skin of green …

Tipping Points In Crayfish Management: Exploring Population Dynamics With The Bifurcations Activity In Slopes, Evan Inrig, Benjamin Lucas

Seaver College Research And Scholarly Achievement Symposium

Slopes is an interactive environment for exploring numerical methods and graphical solutions to ordinary differential equations. The app launched with five activities for exploration: slopefields, phase planes, oscillations, solutions to systems, and numerical methods for approximation. Bifurcations is a new sixth activity that we designed to investigate changes in the long term behavior of solutions to autonomous differential equations. This activity displays a slopefield and implements the ability to add solutions, but also introduces two new views that show how varying a single parameter impacts the values and stability of equilibrium solutions. We demonstrate the value of the new bifurcations …

Where The Ice Plant Reaches: Mapping Biodiversity Shifts Along Distance Gradients From Carpobrotus Edulis, Leon Hong, Patrick Thomas, Steven Kim, Florybeth La Valle

Seaver College Research And Scholarly Achievement Symposium

This study examined the influence of the invasive ice plant Carpobrotus edulis on species richness and biodiversity in Bluffs Park. Because previous research suggests that C. edulis suppresses nearby native flora, our team used quadrat and transect sampling to measure plant diversity at seven distances from the invasion edge (1 m, 3m, 5m, 10m, 15m, 20m, 30 m). Flora were identified using iNaturalist and recorded. Shannon diversity showed no significant change with distance (ANOVA: F₆,₄₂ = 1.34, p = 0.18), and assumptions of normality and equal variance were met. Tukey’s post-hoc tests found no significant pairwise differences. Community composition based …