Ecology and Evolutionary Biology Commons^™

Plant Communities In Dynamic Systems: How Disturbance Influences Coastal Plant Community Structure And Function, Joseph K. Brown

Theses and Dissertations

As the climate continues to change it is difficult to predict how barrier island function will respond to global change drivers accompanying predicted climate change. Disturbance frequency and nutrient enrichment in coastal regions are drivers of plant community change that increase with climate change. Plant communities on barrier islands are not only tightly connected to barrier island function but are also some of the first communities affected by environmental change, making them a critical piece in understanding how current drivers of global change will impact the future of barrier islands. The objective of my dissertation was to observe and manipulate …

Movement, Home Ranges, And Population Estimates Of Spotted Turtles (Clemmys Guttata) During A Rainy Breeding Season In Virginia, Lauren J. Jurczak

Theses and Dissertations

Spotted turtles (Clemmys guttata) use a complex of wetland and terrestrial habitats for survival and reproduction. Precipitation expands and creates larger and more numerous ephemeral pools available to spotted turtles on the landscape. In this study, I investigated the effects of precipitation on movement patterns and ephemeral pool usage by spotted turtles in southeastern Virginia. I conducted a 4-month capture-mark-recapture study alongside a telemetry study to estimate population size and to quantify movement of spotted turtles across the landscape during the breading season. A change point analysis was used to detect discrete changes in turtle behavior and whether …

Effects Of Abiotic And Biotic Factors On Hornworm Distributions, Emelia O. Kusi

Theses and Dissertations

Determining the drivers of species occurrences is a central topic in ecology. Both abiotic and biotic factors are important predictors of species distributions, yet most species distribution models consider abiotic variables only. In this study, the influence of abiotic and biotic factors on current distributions of herbivores, Manduca sexta, and Manduca quinquemaculata, their major cultivated and wild host plants, and a parasitoid, Cotesia congregata, was quantified using an ensemble of three models (generalized linear model, maximum entropy, and random forest). The predictive ability of abiotic-only, biotic-only, and abiotic-biotic models was evaluated. Winter temperatures and precipitation (i.e., precipitation of …

Water Clarity At The River-Estuary Transition Zone: A Comparative Study Of The James, Mattaponi, And Pamunkey Sub-Estuaries, Rachel Henderson

Theses and Dissertations

Water clarity is a key parameter for monitoring water quality and often used to assess habitat suitability for submerged aquatic vegetation (SAV). Light attenuation, a measure of water clarity, is impacted by colored dissolved organic matter (CDOM), and by suspended particulates which include living and non-living components. We anticipated that the relative importance of these factors in regulating light attenuation would vary among the upper portions of three sub-estuaries differing in morphometry, hydrology, and degree of human influence. The James is characterized by eutrophic conditions and high algal abundance, whereas the Mattaponi and Pamunkey exhibit lower phytoplankton production. The Mattaponi …

A Spatiotemporal Assessment Of Fish Assemblage Response To Land-Use Change And The Evaluation Of Edna Metabarcoding For Describing Diverse Fish Communities, Timothy M. Owen

Theses and Dissertations

Fish assemblages are often assessed as a biological proxy for environmental health. While humans value healthy environments for the ecosystem services and recreational opportunities they provide, it is increasingly evident that such resources can be paradoxically degraded by anthropogenic activities. In this investigation, we studied the relationship between different intensities of anthropogenic land-use change and habitat-driven fish assemblage response across multiple spatiotemporal scales. Secondarily, we explored the efficacy of eDNA metabarcoding against conventional electrofishing techniques for the purpose of describing complete fish communities. This study was conducted in the Tuckahoe Creek basin near Richmond, Virginia. This James River tributary serves …

Successional Changes In Carbon Storage Are Sustained In A Temperate Forest Across Different Initiating Disturbances, Cameron Clay

Theses and Dissertations

Managing forests for carbon (C) sequestration requires an understanding of how disturbance history shapes C pools and fluxes over successional time. At the University of Michigan Biological Station, we examined how two stand establishing disturbances influenced C pools and fluxes over 100+ years of succession, comparing these secondary forests with “legacy” late-successional stands encompassing ages and compositions that would be present in the absence of region-wide stand-replacing disturbance. Our work utilized measurements taken between 2014 and 2020 from separate experimental forest chronosequences initiated following clear-cut harvesting only or clear-cut harvesting and fire, along with three >130-yr-old late successional stands comprising …

The Mechanisms And Consequences Of Shrub Encroachment On The Virginia Barrier Islands, Lauren K. Wood

Theses and Dissertations

Shrub encroachment is a global phenomenon driven by direct and indirect anthropogenic influence which alters plant communities and ecosystem function. Many studies have investigated drivers and consequences of woody plant establishment, but mesic landscapes are underrepresented in the literature. My objective was to assess the mechanisms of Morella cerifera encroachment into coastal mesic grassland, the potential for self-reinforcement, and consequences on community composition, nutrients, and landscape productivity. I studied temperature and water microclimate modification by Morella cerifera presence and removal to understand ecosystem engineering and community composition changes. Additionally, I examined the influence of shrubs on surrounding grassland species traits …

Variation In Personality Among Semi-Wild Myanmar Timber Elephants, Sateesh Venkatesh

Theses and Dissertations

This study examines two personality traits: exploration and neophobia, which could influence human-elephant conflicts. Thirty-one semi-wild elephants were tested over two trials using a custom novel puzzle tube containing three tasks and three rewards. Our studies show that elephants do vary significantly between individuals in both exploration and neophobia.

Morphological Assessment And Mitochondrial Dna Analysis Of Roadside-Skippers (Genus Amblyscirtes, Family Hesperiidae) Occurring In Arkansas, Sachith Srikanth

Theses and Dissertations

Amblyscirtes linda is a candidate for federal listing under the Endangered Species Act (1973). The present study, funded by the U.S. Fish and Wildlife Service and the Arkansas Game and Fish Commission, aims to gather data that will enable a decision regarding federal listing to be made. It is understood that the conservation status of Amblyscirtes linda cannot be accurately assessed without examining other congeneric species with which it cooccurs and can be easily confused. This confusion is due to morphological characteristics being very similar in the genus. We therefore studied morphological and molecular means of identification, as well as …

Assessment Of Wild Ring-Tailed Lemur (Lemur Catta) Populations In Southwestern Madagascar With Implications For The Illegal Pet Trade, Samantha D. Calkins

Theses and Dissertations

Accurate population estimates are critical to inform conservation management of species. Incomplete sampling can lead to population underestimates and lacking conservation efforts. Population surveys are important for assessing human and animal welfare to allow for targeted conservation action. Recent ring-tailed lemur (Lemur catta) surveys have led researchers to conclude that L. catta populations are crashing. This has generated much attention and alarm, but may also be based on incomplete information. To better understand population dynamics, more thorough sampling is needed. Here, we survey five such sites to reassess the presence and abundance of L. catta in these locations. …

Estimating Taxonomic Diversity Using Centrum Growth Profiles And Stinger Morphology Of 36 Million Year Old Stingrays From North Dakota, Persia S. Tillman

Theses and Dissertations

Stingrays are a diverse and popular group of vertebrates; however, nothing is known about the relationships between growth biology and climate change. Freshwater stingrays once inhabit the United States and Canada during very warm times in the geologic record. No stingray material has been recorded from the northern part of the United States for the last 33 million years. The Earth’s climate cooled from 50 to 33 million year ago when many warm adapted organisms were relegated to warmer, southern latitudes in North America. Today, freshwater stingrays only inhabit subtropical and tropical environments. We are interested in the freshwater stingrays …

Earliest Known Material Of Amia, Bowfin, From The Sentinel Butte Formation (Paleocene), Medora, North Dakota, Abby Grace Moore

Theses and Dissertations

Amia calva is an icon in the field of comparative osteology, yet we have a poor understanding of the evolution of the genus because many fossil amiid bones have gone unidentified. Here we identify new material of the genus, Amia, with evidence of two unidentified species. Previously, the oldest known material identifiable as Amia cf. A. pattersoni, was a specimen from the Paleocene epoch of Alberta, Canada approximately 58 million years in age. Fossils of the two unidentified species of Amia were found in the Sentinel Butte Formation, a geologic formation of Paleocene age (~ 60 million years …

Characteristics And Spatial Heterogeneity Of Prescribed Fire Behavior In North Dakota Grasslands, Megan Elizabeth Zopfi

Theses and Dissertations

Fire is a critical physical and chemical process required to sustain many grassland ecosystems. In North America, observations of grassland fire behavior in warm-season, southern grasslands are commonly used in fire behavior modeling efforts across the Great Plains. However, grasslands of the northern Great Plains contain a greater component of cool-season vegetation that may generate different fire behavior. To further our understanding of prescribed fire behavior in North Dakota grasslands, we quantified fuel, weather, and fire behavior characteristics associated with 27 prescribed fires conducted across three sites in North Dakota. We sampled 27 points on each fire arranged into a …

Belowground Characteristics Of Dominant Coastal Dune Grasses And Potential Community-Level Effects On Coastal Erosion, Shannon L. Walker

Theses and Dissertations

Natural dunes arise out of complex relationships between ecological, hydrological, and geological processes and are important for reducing erosion along coastlines. Aboveground structures of coastal dune grasses are known to impact erosional dynamics, and recent studies have shown that belowground structures—such as roots, rhizomes, and belowground stems— may be important in erosional resistance. My objectives were to 1) characterize above- and belowground characteristics of prominent dune grasses and 2) combine these data with functional group abundances and distribution to evaluate community effects on two adjacent locations of distinctive morphology and erosional characteristics and their response to storm disturbance. Whole plant …

The Origin And Evolution Of Flower Characters In Angiosperms With A Case Study On The Genetic Basis Of Zygomorphic Corolla Development In Bee And Hummingbird Pollinated Species Of Schizanthus (Solanaceae), Ghadeer Bukhari

Theses and Dissertations

This Ph.D. dissertation investigates two main projects separated into two chapters, one for each. The first chapter explores the evolution of flowering plants (angiosperms), a macro-scale study. The second project is on a micro-scale that focus on exploring the genes that regulate the similarities and the differences of flower morphology reflecting their different pollination syndromes in two species of Schizanthus (Solanaceae), i.e., S. pinnatus, a bee-pollinated flower, and S. grahamii, a hummingbird- pollinated flower.

In the first chapter, I used floral diagrams to study the origin and the evolution of floral traits in angiosperms, a new set of morphological data …

The Heat Is On: Comparison Of Thermoregulatory Behavior In Parasitised Versus Unparasitized Caterpillars Of The Tobacco Hornworm, Manduca Sexta (L.) [Lepidoptera: Sphingidae], Jessica M. Johnston

Theses and Dissertations

Insect thermoregulatory research has demonstrated evidence of variation occurring within and among species with respect to infection, pathogens, and parasitism, but few studies have examined differences in thermoregulatory behavior in a host-parasite system with a coevolved symbiotic virus. I investigated the role of parasitism by Cotesia congregata (Say) (Hymenoptera: Braconidae) on the thermoregulatory behavior of Manduca sexta (L.) (Lepidoptera: Sphingidae) using an experimental design in a thermal gradient chamber and a complementary observational field study on wild M. sexta collected from tobacco farms. Parasitism and larval age were not found to have a significant effect on the preferred body temperature …

Plant-Pollinator Associations In An Eastern Serpentine Savannah And The Effects Of Overbrowsing, Allyson Richins

Theses and Dissertations

Chapter 1: Native plant response to deer overbrowsing in a serpentine savannah

Plants are particularly vulnerable to physical disturbance in low productivity areas, due to a high cost of replacing lost plant tissue. In the eastern United States, serpentine grasslands are fragmented ecosystems with high concentrations of rare endemic plant species, low concentrations of soil nutrients, and uncontrolled deer overpopulation. This study assessed functional responses of native angiosperms in a rare eastern serpentine savannah to selective deer browsing. Plant count, flower count, floral area, vegetative area, and plant height of 10 serpentine plant species were compared inside and outside of …

Taxa Specific Responses To Flooding Shape Patterns Of Abundance In A River Rock Pool Metacommunity, Charles R. Stunkle

Theses and Dissertations

Connectivity and habitat area are important landscape characteristics that drive patterns of abundance and diversity across scales. However, responses to connectivity and patch size are dependent on species traits. Riverine landscapes are highly dynamic both spatially and temporally with hydrologic connectivity being a major driver of abundance and diversity. Here we modeled densities of the Virginia river snail and skimmer dragonfly nymphys, two taxa with differences in their dispersal abilities and life histories, as a function of flooding, patch area, and season in over 300 riverine rock pools. We found key differences in how each taxon responded to these predictors …

Evidence Of Local Adaptation To Climate In An Invasive Ectotherm: A Study On The Eurasian Gypsy Moth (Lymantria Dispar) In North America, Phillip M. Gibbs

Theses and Dissertations

Invasive species exist in nearly every ecosystem both terrestrial and aquatic. Improving our understanding of the mechanisms that shape the ability of these organisms to physiologically cope with their surroundings will be crucial to preparing for future impacts of climate change. The Gypsy Moth (Lymantria dispar) has been expanding its range across North America over the last 100+ years since its arrival in Medford, Massachusetts. This study quantifies upper thermal limits (UTL) across 8 different populations of L. dispar in North America and seeks to determine if signals of local adaptation to climate across a latitudinal gradient may …

Assessing The Feasibility Of Freshwater Mussel Restoration In Urban Streams., John-Reid Ryan

Theses and Dissertations

Abstract

The main objective of this study was to determine whether introduced freshwater mussels (Alewife floater, Utterbackiana implicata) can survive and grow in urban streams in the James River watershed. A secondary objective was to assess differences in U. implicata survival and growth of in the context of differing water quality and food resource conditions among three urban sites and three rural sites. Results from this study show large differences in growth and survivorship of mussels across sites. Higher survivorship was observed among mussels stocked into rural streams (35% and 44%) in comparison to urban streams (3%, 6% and 14%). …

Bee Diversity Of Three Appalachian Shale Barren Sites, Olivia C. Latham

Theses and Dissertations

Insect pollination is vital to ecosystem function. However, climate change, habitat loss, pesticides, and a variety of other anthropogenic sources are contributing to a decline in pollinator diversity. Fragile small ecosystems with a high composition of specialized plant species that rely on specific pollinators such as Appalachian shale barrens, are especially at risk of losing biodiversity. This study combines the use of active sweep net sampling of endemic shale barren forbs and passive trap methods over the course of a bloom season (April-August) in three barren sites to identify bee community populations and visitation relationships between pollinator species and endemic …

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …

The Influence Of Breeding Density On Female Aggression, Parental Care, And Ornamentation In A Secondary-Cavity Nesting Warbler, Elsa B. Chen

Theses and Dissertations

Tradeoffs between individual survival and reproductive success associated with aggressive behaviors are a driving force of evolution, but these tradeoffs are often overlooked for aggressive conspecific interactions between females. For avian males, it is well documented that more aggressive individuals tend to provide less parental care. In the few studies that address this in females, the tradeoffs seem to be more context-dependent, varying due to factors such as predation pressure and habitat quality. The relationship between female ornamentation and aggression is similarly understudied, but evidence suggests that both aggression and ornamentation are important traits involved in social selection – the …

Stimulated Growth Response To Sand Burial Of A Coastal Shrub, D. Nicole Keller

Theses and Dissertations

Drivers of vegetation zonation on barrier islands are complex and interconnected. Sand burial is a strong driver in dynamic coastal systems, especially in the foredune community. However, it is not well understood how burial impacts the interdunal swales communities and it is especially difficult to separate the effects of burial from salinity. Climate change is altering the frequency of overwash events as well as expanding the range of the native shrub, Morella cerifera, on the Virginia barrier islands. To accurately forecast island response to climate change it is important to understand how the shrub responds to sand burial. Juvenile …

A Male-Female Genotype-By-Genotype Interaction Mediates The Effect Of Mating On Female Immunity In Decorated Crickets, Kylie J. Hampton

Theses and Dissertations

Sexually antagonistic coevolution should lead to the rapid divergence of male and female genotypes related to the effects of ejaculatory substances on female physiology. Hence, the outcome of mating should depend on an interaction between male and female genotypes. Although mating has been shown to influence female immune responses in diverse insect taxa, a male-female genotype-by-genotype effect on female immunity post-mating remains largely unexplored. Here, we investigate both the effects of mating on female immunity and the potential for a male-by-female genotype interaction on the form and magnitude of this response in decorated crickets. Females from three distinct genotypic backgrounds …

Comparison Of Play Frequency In Four Sympatric Monkey Species In Kibale National Park, Uganda, Sara G. Lucci

Theses and Dissertations

This study describes play in red colobus (Procolobus rufomitratus), grey-cheeked mangabeys (Lophocebus albigena), black-and-white colobus (Colobus guereza), and redtail monkeys (Cercopithecus ascanius) to test Instinct-Practice Theory. Solitary locomotor play was different among the species. Rough-and-tumble play was different between male and female redtail monkeys. These results partially support Instinct-Practice Theory.

Connecting The Dots: Exploring The Relationship Between Avian Eggshell Pigmentation And Paternal Provisioning Effort, Kara E. Hodges

Theses and Dissertations

In a number of bird species, eggs laid by females breeding in the same population can vary extensively in the extent of their eggshell pigmentation, but the adaptive significance of this intraspecific variation remains unknown. One hypothesis posits that shell pigmentation is an honest signal of female quality that reflects her level of oxidative stress, one that is used by males to inform their subsequent paternal investment. We employed a reciprocal clutch cross-fostering design to test whether provisioning by male house wrens (Troglodytes aedon) responds to the clutch pigmentation of their mates. In experimental replicates, dark clutches were swapped with …

Enclosures And Dichotomies: Coexistence Vs. Distance In The Poems Of John Clare, Jordan P. Finn

Theses and Dissertations

John Clare’s poetry emphasizes an affinity with environment by suspending the distinction between the inside (subject) and the outside (object). Clare’s identification with objects and perception rather than subjects and aesthetics renders his work as a prescient and radical example of ecological poetry in the Romantic period. Raymond Williams’ “green language” and Timothy Morton’s ambient poetics both cite Clare as an ideal figure for their above theories and evoke Clare as a writer who positions the environment as governing thought rather than thought governing the environment. This thesis especially relates Clare to Morton’s Ecology without Nature, a study of …

Contagious Yawning In The Domestic Cat (Felis Catus), Ariel M. Lombardo Aghishian

Theses and Dissertations

This study investigates contagious yawning in domestic cats towards their owners, looking at potential links with empathy. Results showed no significant difference in yawning between conditions. The solitary nature of wildcats and their shared ancestor, and the unique social behavior in domesticated cats may explain these findings.

Contributions Of Historical Ecology To Ecological Services Assessments In The Lower Rio Grande Valley Texas, Julianna Katherine Schaefer Kurpis

Theses and Dissertations

Historic and current anthropogenic land-use activities affect ecological functions and ecosystem services quality. The clearing of native Tamaulipan thorn forest and riparian forests for agricultural use and expansion followed by rapid urbanization and population growth resulted in profound ecological impacts to the Lower Rio Grande Valley (LRGV), Texas. The goals of this study are 1) document trends in land use change and vegetation health in the LRGV 2) evaluate and demonstrate the application of the Ecosystem Services Identification & Inventory Tool (ESII Tool) for collecting ecological data and measuring percent ecological performance and 3) use historical ecology indicators to compare …