Population Biology Commons^™

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 …

Singing Not To Sing: The Interplay Of The Environment And Behavior On The Reproductive Success Of Forest Breeding Migratory Birds, Miranda Bliss Zammarelli

Dartmouth College Ph.D Dissertations

Habitat selection is a key behavior that has consequences for fitness, which can shift with environmental variation. The environment can affect reproductive success indirectly by shaping behavior or via direct impacts. Many forest breeding migratory birds choose a habitat by establishing territories. To understand the interplay of environment and behavior on the reproductive success of forest breeding migratory birds, I leveraged long-term data and newly collected species-specific data from Hubbard Brook Experimental Forest, New Hampshire, USA. I analyzed over 50 years of territory maps from seven species occupying a 10-ha plot to understand how birds distribute themselves in a habitat. …

Hidden Diversity In A Clonal Endemic: Insights Into Clematis Socialis From A Population Genetics Perspective, Joanna M. Lapoint

Theses

Clematis socialis (Kral) is a rare, federally endangered perennial species restricted to a small number of fragmented populations in Alabama and Georgia. The species exhibits extensive clonality and limited sexual recruitment, characteristics that complicate expectations regarding genetic diversity and population connectivity. Despite its conservation significance, genome-wide assessments of population structure have been lacking. We used genotyping-by-sequencing (GBS) to generate a genome-wide SNP dataset for 170 individuals sampled from six natural populations. Population structure and genetic differentiation were evaluated using Bayesian clustering, analysis of molecular variance (AMOVA), pairwise FST estimates, and network-based visualization. Analyses revealed strong genetic structuring among populations and …

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 …

Bird Population Response To Abiotic And Biotic Stresses In Urban & Restored Oak Savannah Habitat, Annabelle Ball

Posters - 2026

Birds are heavily impacted by urban development. Many experience habitat fragmentation and removal of food sources. However, other species can adapt to and even thrive in urban environments, thanks to certain tree species, bird feeders, and buildings. In North America, the house sparrow and the European starling are invasive species that benefit from urban environments (Bartelt, 2011; Fitzwater, 2014). Meanwhile, many habitats across the continent are experiencing restoration/rewilding efforts for the benefit of birds. One such habitat is the oak-savannah, which is characterized by 10-30% canopy cover and a mixture of prairie & woodland vegetation, supporting a high diversity of …

Testing The Intermediate Disturbance Hypothesis On Anthropogenic Pressure In Central Alabama, Gavin Terrell

Theses

Biodiversity is fundamental to maintaining ecosystem structure and function globally. Prior to the late 20th century, ecological theory generally predicted that biodiversity would be highest in systems experiencing minimal disturbance. However, Joseph H. Connell challenged this view with the Intermediate Disturbance Hypothesis (IDH), which posits that species diversity peaks at intermediate levels of disturbance and declines under conditions of both low and high disturbance. Although widely cited, the applicability of the IDH to natural systems remains debated, particularly in the context of anthropogenic disturbances and when diversity is measured beyond species richness alone.

This study evaluated the predictions of the …

Fisheries Management Paper No.312: Discussion Paper On Management And Licensing Options For The Charter Industry - Statewide Strategic Review Of Western Australia’S Charter Fishing Sector, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Management Papers

This consultation paper has been prepared to support the statewide strategic review of Western Australia’s (WA) charter fishing sector, which was initiated as a government commitment.

The paper details issues and proposals relating to the management and licensing framework, development opportunities and representation model for the charter fishing industry. The proposals have been developed in consultation with the Charter Review Working Group. The Department of Primary Industries and Regional Development (DPIRD) now seeks comment from relevant stakeholders on the issues and proposals outlined within this paper.

Comments provided will assist in providing advice and recommendations to the Minister for Fisheries …

Alabama Prairie Reconstruction: Comparing Management Pathways For A Southeastern Landscape, Cecelia R. Geyer

Theses

Southeastern prairies are highly biodiverse yet increasingly threatened by land-use change, fire suppression, and habitat fragmentation. These disturbance-dependent systems rely on periodic fire and grazing to maintain plant diversity and ecosystem function. This study evaluates prairie restoration strategies by testing predictions from the Intermediate Disturbance Hypothesis and the Patch Mosaic Burn Hypothesis. The study site was divided into three treatments: prescribed burned only (B), prescribed burned with mowing (BM) to simulate grazing, and an undisturbed control (C). A standardized mix of native plant seeds was broadcast across all treatments. Ecosystem health and function were evaluated using plant community diversity and …

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 …

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 ( …