Population Biology Commons^™

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 …

Determining The Influence Of A Low-Head Dam On Macroinvertebrate Communities In The Bouie River, Natalie Santiago

Honors Theses

The Bouie River is a tributary of the Leaf River and belongs to the Pascagoula River watershed, the latter of which has no flow impediments in the form of sills or dams. The Bouie River has been heavily altered in the lower 10 river kilometers (rkm) from aggregate mining (creating a series of deep gravel pits) and the presence of an earthen and concrete low-head dam (sill) located 6 rkm from the mouth of the river. However, despite these alterations, the immediate stretch of river below the low-head dam is a known spawning habitat for diadromous fish species, including the …

Sibship Analysis Of Fall And Spring Spawn Gulf Sturgeon Eggs In The Choctawhatchee River, Florida, Lyric Mccullouch

Honors Theses

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is an anadromous species that inhabits rivers along the northern Gulf of Mexico. Facing challenges from overfishing and habitat alteration, the Gulf sturgeon is listed as threatened under the Endangered Species Act. This study investigated the genetic distinctiveness of fall and spring spawning groups of Gulf sturgeon in the Choctawhatchee River, a critical habitat for the species. In this study, I used microsatellite loci to analyze Gulf sturgeon eggs previously collected in the fall and spring of 2019 and 2020. The goals of this study were to verify the genetic identity of …

Survey Of The Bolctes From Fish River Nature Preserve, Noah T. Nelson

Honors Theses

Boletes are a special kind of mushroom inside of the Kingdom Fungi that are distinguished from other mushrooms by their uniquely pored hymenium, as opposed to gills. Many boletes are ectomycorrhizal, meaning they are mutualists with vascular plants, and thus beneficial to the overall health of the terrestrial ecosystem. Some are well-known for their edibility and are of economic importance. In the United States 59 genus-level clades comprising 290 operational taxonomic units have been reported. The southeastern US and Gulf Coast regions however are less researched and recorded for their mushroom ecology. In Alabama, only 56 bolete species have been …

Impacts Of Disturbance And Nutrient Addition On Coastal Dune Arthropod Communities, Kayla Beitzel

Honors Theses

Coastal dune ecosystems are globally distributed ecosystems that occur from the tropics to the poles and serve as the first line of defense during storms. They are critical habitats for a variety of organisms and also play a critical role in stabilizing coastal habitats. These systems face increased pressure via urban development, recreational expansion, and sea-level rise (Newman et al. 2023; Webster et al. 2005). Insects are vital consumers in coastal ecosystems and act as regulators of plant growth. Low-diversity ecosystems, like coastal dune systems, often contain a higher abundance of low-diverse insect consumers (Ripple et al. 2021), which can …

A Camera Trap Study Of Scavenger Species On The University Of Mississippi Campus, Lise Larsen

Honors Theses

This is a camera trap study to understand what kind of mammalian scavenger community we have on the University of Mississippi campus and where they are most prominent. Three motion-triggered cameras were used to survey ten buildings on campus over ten weeks. A low number of individuals were caught on camera during this study. There were limitations on this study such as a low number of cameras and a short span of time. More research needs to be done to understand the scavenger community on this campus.

Striped Blenny (Chasmodes Bosquianus) Presence And Behavior Between Sunrise And Sunset At Oyster Landing, South Carolina, Madeline Schuetze

Honors Theses

Lunar and diel cycles of fishes can help to interpret their behaviors during their reproductive season. Temperate estuaries are used by many benthic fishes for shelter and reproduction. This study examined the behavior and presence of striped blennies (Chasmodes bosquianus) during diel and lunar cycles. PVC pipe shelters were placed to mimic oyster shell nests, a natural habitat for blennies, and cameras were placed to monitor these shelters in April, May, and June 2022, during the striped blenny reproductive period. Video footage was reviewed and analyzed for the presence and behavior of both male and female blennies. Male presence …

Species Diversity Of Coleoptera Populations In An Urban Garden In Chattanooga, Tennessee, Mallory Anderson

Honors Theses

Insects are an essential part of the function of ecosystems. The majority of entomological faunistic research has been conducted primarily in rural areas due to high diversity, space for bulky traps, and less outside influence from human activities. However, the need for time-series insect biodiversity data, in rural areas and urban areas alike, is paramount in the wake of our current sixth mass extinction event. Previous research has shown that the greater Chattanooga area is comprised of a diverse population of insects in the Coleoptera (beetles) order, and as shown in the University of Tennessee at Chattanooga’s (UTC) Insect Collection. …

Effect Of Temperature On The Microbiome Of A Laboratory-Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna L. Mitchell

Honors Theses

Haemaphysalis longicornis ticks are invasive to the United States with potential to transmit several tick-borne pathogens that are native to the United States. Based on existing locations of H. longicornis in its native regions in Asia, as well as its invasive populations that are established in the United States, several geographic range prediction models have been produced to help understand future range expansion and distribution of this invasive tick in North America. Unfortunately, these models do not all agree and there is uncertainty associated with the potential geographic range expansion of H. longicornis ticks in North America. Climate can affect …

Analysis Of Ecological Tradeoffs Between Congeneric Shrimp In Coastal Mississippi Waters, Baylor K. Lynch

Honors Theses

Palaemonidae is an ecologically important and abundant family of shrimp that link the benthos to many estuarine food webs. Palaemon pugio and Palaemon vulgaris regularly co-occur along estuarine edge habitats despite previous studies suggesting different preferred sediment types and salinity regimes. The objective was to determine if competition is occurring between the congeners by comparing their relative abundance and assessing isotope niche space along an estuarine gradient. I seasonally sampled various edge habitats at four sites throughout Biloxi Bay, MS, using fyke nets fished over a tidal cycle from November 2020 to November 2021. Collected organisms were identified to the …

Striped Blenny (Chasmodes Bosquianus) Behavior And Shelter Use In A Southeastern Salt Marsh Tidal Creek, Brooklyn Johnson, Juliana Harding

Honors Theses

Temperate estuaries are important habitats for resident species and maturing juvenile transient fishes. The North Inlet estuary, SC resident fish fauna includes the Striped Blenny (Chasmodes bosquianus) and Crested Blenny (Hypleurochilus geminatus). Individual blenny males occupy habitat shelters year-round. During breeding season, blenny males attract mates to nest and protect developing embryos within the nest. Salinity requirements establish blenny spatial distribution in the estuary. Seasonal spawning activity by these temperate blenny species is related to water temperature and seasonal productivity patterns. Blenny nest site occupancy patterns relative to the lunar cycle, water depth, and salinity were …

Density Dependent Growth Of Pseudomonas Fluorescens In The Presence And Absence Of C. Elegans Predation In Liquid Media, Jack Landmann

Honors Theses

The purpose of this study was to understand the predator-prey relationship between C. elegans worms and P. fluorescens bacteria in liquid media. We were aiming to create a predation model of the relationship between these two species.

This study was performed through three experiments. Using 96-well plates, we were able to measure the change in optical density (OD) of these wells and calculate the growth rate. This growth rate was then graphed and analyzed. The first experiment contained P. fluorescens and KB liquid media, this study demonstrated that the bacterial population has a carrying capacity. We were also able to …

Genetic Diversity & Connectivity Of Chasmanthium Latifolium (Poaceae) In Pennsylvania & The Effect On Conservation Status Of A Rare Species, Jonathan D. Hayes

Honors Theses

Chasmanthium latifolium (Michx.) Yates (Poaceae) is a loosely colonial, rhizomatous, perennial grass species that lives in riparian habitats, making it fittingly referred to as river oats. Native to the southern Midwest and the eastern half of the United States, C. latifolium reaches the northeastern edge of its range in Pennsylvania. Within Pennsylvania, eleven extant C. latifolium populations are found along four waterways: the Monongahela River, the Susquehanna River, and two tributaries to the Susquehanna River. This limited state distribution exhibits an east-west disjunct distribution, where western populations are largely separated from eastern populations with one centrally located population. Between the …

Blenny Territoriality At Oyster Landing, North Inlet Estuary, South Carolina: Seasonal Patterns And Ecological Factors, Sydney Davis, Juliana Harding

Honors Theses

Temperate oyster reef blennies use oyster shells that are still articulated as habitat year round. During the breeding season when water temperatures are > 18-20°C, many species of blenny males use the oyster valves as nesting sites. Male blennies exhibit territorial behavior when guarding their nesting sites and can interact differently with conspecific and transient species. Striped blenny (Chasmodes bosquianus) and freckled blenny (Hypsoblennius ionthas) behavior was described from April 2020 to August 2020 at Oyster Landing, North Inlet estuary, South Carolina to quantify typical blenny behavior, general presence or absence of residents, and potential environmental parameters …

Infaunal Bivalve Density And Richness In North Inlet Estuary, South Carolina: Seasonal Patterns And Ecological Factors, Valerie M. Knowles, Juliana Harding

Honors Theses

Estuarine bivalves recruit to benthic habitats after the larvae are in the planktonic stage. The observed infaunal bivalve density relates to larval supply from adult reproduction during warmer months as well as larval and juvenile mortality post-recruitment. The purpose of this research was to examine annual and seasonal patterns of infaunal bivalve density and richness in the context of habitat water temperature and salinity. Cores were collected biweekly from Bly Creek in North Inlet estuary between January 2019 and February 2020. Temperatures ranged from 9-30 ºC and salinity ranged from ~17-36 psu. Bivalves were sieved out of the cores, counted, …

Population Genetics Of A Recent Range Expansion By The Southern Pine Beetle, Dendroctonus Frontalis, Into The Northeastern United States, Megan Stubbs

Honors Theses

Population genetics as a field of study aims to determine the genetic variation among individuals in a population, and differences among populations. Certain population genetic analyses can provide such information and be used to better understand the biological aspects to a species’ expansion beyond its native range. The southern pine beetle (SPB), Dendroctonus frontalis, has become an invasive pest to pine forests in northeastern United States with its recent range expansion. Nine microsatellite loci were first developed and then used in analyses. To determine what the genetic variation is among individuals in SPB populations across its entire range, including …

Is Anyone Home? Year Round Site Fidelity Vs. Temporal Territories In Estuarine Blennies, Nicholas Govostes

Honors Theses

Temperate oyster reef blennies use articulated oyster shells as nest sites in warmer months during breeding season but little is known about their site fidelity during non-breeding season. Unlike coral reef blennies that occupy territories year-round, rocky intertidal temperate blenny species display temporal territories and seasonally migrate into breeding shelters. Striped blenny (Chasmodes bosquianus) shelter use was described from November 2019 through March 2020 at Oyster Landing, North Inlet estuary, SC to quantify the proportion of daylight hours when fish were in residence and describe potential relationships between shelter occupancy and neighboring fishes. Replicate PVC shelters were monitored …

Development Of Methods To Track Oyster Movement Under Field Conditions In North Inlet Estuary, South Carolina, Alyssa M. Leclaire

Honors Theses

Eastern oyster (Crassostrea virginica) reefs provide important habitat structure and ecosystem services in saltmarsh tidal creek estuaries. Reef persistence depends on growth of resident individuals and regular recruitment to maintain suitable shell substrate. Boat wakes potentially physically displace oyster clumps. The objective of this research was to develop methods to track oyster clump position and biomass on two natural fringing oyster reefs in North Inlet estuary, South Carolina. Boat traffic (number of boats making wakes per day), oyster clump displacement (cm/d) over time, oyster biomass (g dry tissue), and condition index (biomass/g dry shell weight) were quantified from …

Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray

Honors Theses

Hybridization and introgression are two important evolutionary mechanisms that can increase genetic diversity. Interesting introgression patterns can form when parental species have genes that confer some adaptive benefit to the organism. The Fundulus notatus species complex contains species with various identifying characterisics. Fundulus notatus, the blackstripe topminnow, and Fundulus olivaceus, the blackspotted topminnow, are closely related and occupy many of the same rivers in their preferred niches. These two species often hybridize and form hybrid zones where their niches overlap. We studied two hybrid zones located in the Tombigbee River and Spring River. Within each hybrid zone, we …

Density And Species Richness Of Macrofaunal Benthic Bivalves In North Inlet Estuary, South Carolina, Richard Hawley, Juliana Harding

Honors Theses

Marine benthic bivalves are consumed by higher trophic levels. Bivalve species richness and density depend on temperature, salinity, and location. Biweekly core samples were collected from Bly Creek from 12/2017 to 12/2018. Benthic macrofaunal bivalves were counted and identified to describe density and species richness. Bivalves were also photographed for species identification. Bivalves composed 0% to 17% of the total macrofauna. The maximum bivalve density (8,149 bivalves/m²) was recorded on December 23, 2018. The fewest bivalves were observed from December 2017 through March 2018. Eight bivalve species were recorded during 2018; at least one species was present year-round. …

Demersal Fish Use Of Printed Oyster Shells As Nesting Habitat In North Inlet Estuary, Sc, Annie Boyd, Juliana Harding

Honors Theses

Temperate estuarine blenny species establish subtidal territories and nesting sites. Four blenny species co-occur in North Inlet, SC including the striped blenny, Chasmodes bosquianus, crested blenny, Hypleurochilus geminatus, feather blenny, Hypsoblennius hentzi, and freckled blenny, Hypsoblennius ionthas. All four fishes use empty oyster (Crassostrea virginica) shells as nesting sites. Current 3D printer technology was used to create standard nest substrates to describe relationships between blenny habitat use and nest site dimensions. Replicate printed shells of 2 gape widths (5, 7 mm) for each of 2 shell cavity volumes (22 mL, 15mL, Oyster A and …

Tracking The Endangered Northern Black Racer, Coluber Constrictor Constrictor, In Maine To Determine Areas Of Conservation Importance, Josiah Johnson

Honors Theses

The Black Racer (Coluber constrictor) is a large-bodied snake species found across North America. One subspecies, the Northern Black Racer (C. constrictor constrictor) is listed as endangered in Maine because of its restricted range in York County. Racers have generally been found to prefer open habitats and ecotones, but the specific habitat preferences of racers in Maine is unknown, hindering efforts to preserve habitat for racer conservation. To address this knowledge gap, the Maine Department of Inland Fisheries and Wildlife (MDIFW) has an ongoing project tracking black racer movements in Sanford and Kennebunk, Maine, and I had the opportunity to …

Genetic Estimates Of The Number Of Breeding Adults In Alligator Gar From The Choke Canyon Reservoir, Texas, E. Blayne Newsome

Honors Theses

Alligator gar were historically found across the coastal drainages of the Gulf of Mexico and up into the Mississippi River basin. However, their populations are experiencing decline in many portions of their range. Texas seems to have large populations of alligator gar, but state resource officers are seeking to better understand its biology so as to provide appropriate management recommendations to maintain the recreational fishery. In this study, I used genetic techniques to examine a cohort of 144 juvenile alligator gar collected in 2016 in the Choke Canyon Reservoir. By estimating the effective number of breeders and number of spawning …

Assessing Genetic Differentiation Among Populations Of The Invasive Plant Impatiens Glandulifera In Maine, Jordan R. Schoonover

Honors Theses

The annual herbaceous plant Impatiens glandulifera Royle is native to the Himalayas and is a significant invasive species in Europe. In the past century, it was introduced to the United States, where it has become established in 12 states. This study evaluated genetic differentiation among four Maine populations, to address a theory that posits hybridization of distinct lineages as a trigger for invasiveness. Regions of microsatellite repeats were evaluated at two polymorphic loci for 41 plants sampled from the four populations. A striking finding was that the observed heterozygosity was substantially higher than the heterozygosity expected from random combination of …

The Pollination Biology And Mating System Of A Peripheral Population Of Witheringia Solanacea (Solanaceae), Timothy Miller

Honors Theses

Pollinator visitation rates over the life of a flower are determined by pollinator abundance and floral longevity. If flowers are not visited frequently enough, pollen limitation may occur, favoring the evolution of self-compatibility (SC). In plant species with varying SC levels, central populations often are self-incompatible (SI) and peripheral populations are SC. Witheringia solanacea (Solanaceae) is a species that follows this trend with the exception of one population in the Monteverde Cloud Forest Reserve, which is peripheral yet SI. I investigated this population using multiple techniques including floral bagging, pollinator observations, microsatellite analysis, and floral longevity manipulations. My results confirmed …