Ecology and Evolutionary Biology Commons^™

Causes And Consequences Of Space-Use Behavior Under Predation Risk In A Free-Living System, Brian J. Smith

All Graduate Theses and Dissertations, Fall 2023 to Present

Predators can have important ecological effects through killing and eating their prey, the so-called consumptive effect, but predators can also have a nonconsumptive effect (NCE) on their prey – this happens when the risk of predation itself causes prey to alter their behaviors or other traits and these alterations ultimately reduce prey survival, reproduction, or population size. While scientists understand the consumptive effects of predators well, we are still unsure whether NCEs are important in free-living systems. In this dissertation, I sought to better understand the potential NCEs of predators (wolves and cougars) on elk in northern Yellowstone National Park …

Investigating Cause-Specific Mortality Of Sheep To Determine The Impacts Of Carnivores On Domestic Livestock, Nathan Jacob Floyd

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Livestock and carnivores interact in ways that are considered conflict throughout the world. In the western United States, livestock are often grazed on public lands in close proximity to predators in their natural habitat, and can be killed as prey. Livestock losses to predators can threaten rancher’s livelihoods. Sheep and lambs are especially vulnerable to predators due to their small size and lack of defensive abilities. To reduce the impacts that predators have on livestock, it is important for ranchers and wildlife biologists to have an accurate understanding of how many livestock die and are killed by predators when grazing …

How Flow Regime Affects Predator-Prey Relationships Of Stream Darter And Shiner Species, Anna E. Richardson

Biological Sciences Undergraduate Honors Theses

Analysis of the interactions between abiotic and biotic factors of environments and ecosystems is a highly valued area of research. This study focuses on the interactions between the biotic component of predation and foraging of certain stream fish species and the abiotic component of the flow regime that those species reside in. Gut content analysis followed by statistical calculations in the form of t-tests and chi -quared tests were performed on two fish species who both inhabited a stream with a groundwater flashy flow regime as well as a stream with a runoff flashy flow regime. The research showed that …

Intraspecific Variation In Prey Susceptibility Mediates The Consumptive Effect Of Predation: A Case Study Of Yellowstone Elk And Wolves, Lacy M. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The reintroduction of wolves (Canis lupus) to Yellowstone National Park starting in 1995 is an important case study for understanding the consequences of predation on a prey population. Simulation studies conducted prior to and shortly after wolf reintroduction predicted that wolf predation of elk (Cervus canadensis) would have a modest influence on elk abundance. Predation of elk by wolves has been well documented and elk have remained the primary prey for wolves despite a decline in elk abundance. I used two quantitative approaches to estimate the influence of wolf predation on adult female elk survival and …

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 …

Assessing Habitat Suitability Of Ribbed Mussels (Geukensia Demissa) In Georgia Salt Marshes By Examining Predicted Mussel Densities And Mussel Population Parameters, William K. Annis Jr

Electronic Theses and Dissertations

Geukensia demissa (ribbed mussel) is an ecology important bivalve that has the potential to contribute to salt marsh restoration. Understanding the factors that contribute to the distribution of mussels can help inform managers on choosing locations to optimize the survivorship of mussels in restoration projects. This study sought to model mussel densities across the coast of Georgia and to compare predicted mussel densities with mussel population parameters as means to gauge habitat suitability. Mussel densities were collected through field surveys across a range of salt marshes along the coast of Georgia and were compared with spatial data such as distance …

Temporal Factors Affecting Foraging Patterns Of A Diurnal Orb-Weaving Spider, Micrathena Gracilis (Araneae: Araneidae), Mitchell Davis Long

Undergraduate Honors Theses

Several studies have investigated the ecological factors that affect behavior in Micrathena gracilis, a diurnal orb-weaving spider that forages on flying insects during the day. However, none yet have considered how the temporal distributions of prey and predator occurrences shape their daily behavioral rhythms, especially web construction, which involves a heavy energetic investment well in advance of potential nutritional benefit. Recently, several orb-weaving spider species have been shown to exhibit a variety of abnormal rhythms, suggesting that circadian clock-controlled rhythms may play an unexpected role in behavioral evolution. Despite the appearance of significant insect abundance in the evenings, M. gracilis …

Estimates Of Calf Survival And Factors Influencing Roosevelt Elk Mortality In Northwestern California, Erin Nigon

Cal Poly Humboldt theses and projects

Survival of juvenile ungulates is known to be highly variable, yet it is fundamental to understanding the dynamics and trends of wildlife populations. Factors influencing calf survival are poorly understood in northwestern California where Roosevelt elk (Cervus canadensis roosevelti) are known to exist. The objectives of this study were 1) to estimate summer and annual survival rates and determine recruitment rates for Roosevelt elk calves in the area, 2) to evaluate differences in calf survival by examining the effects of individual and population level covariates on summer and annual calf survival, 3) to identify factors influencing the timing …

Bottom-Up Herbivore-Plant Feedbacks Trump Trophic Cascades In A Wolf-Elk-Grassland System, Trevor C. Weeks

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Top-down predator-prey effects that alter the abundance, biomass, or productivity of a population community across more than one link in a food web are referred to as trophic cascades. While these effects have been extensively studied in aquatic environments, fewer studies have examined trophic cascades in terrestrial ecosystems. And fewer still terrestrial studies have tested for trophic cascades between vertebrates and grassland vegetation. Across the globe, grassland plant biomass is driven by both precipitation and non-linear positive feedbacks between grazing and plant productivity, as predicted by the Intermediate Grazing Hypothesis. Yet little is known about the role that apex carnivores …

Predator-Based Selection And The Impact Of Edge Sympatry On Components Of Coralsnake Mimicry, Lauren E. Wilson

Electronic Theses and Dissertations

Studying warning coloration and mimicry is an effective way to understand predator-driven selection and phenotypic diversity. The presence (sympatry) or absence (allopatry) of a toxic model plays a role in shaping mimetic phenotypes. However, the impact of edge sympatry and allopatry on predation of mimetic phenotypes is not well understood. We studied coralsnake mimicry to test how edge sympatry and allopatry affect predation on mimetic phenotypes. Specifically, we tested 1) if overall attack rates varied with edge sympatry of coralsnakes 2) which color patterns conferred a fitness advantage 3) which specific mimetic signal components are important in driving predatory attacks …

Snowshoe Hare (Lepus Americanus) Abundance In Relation To Habitat And Predator Assemblage Across The Apostle Islands, Jarod Reibel

Masters Theses

Snowshoe hares (Lepus americanus) are a climate sensitive species that have a southern range boundary moving northward. Snowshoe hares are found on the Apostle Islands, Wisconsin which are near their southern boundary and differ by island in vegetative and carnivore communities. The archipelago serves as a natural laboratory to assess how top-down and bottomup forces interact and impact snowshoe hare populations. The objectives of this study were to determine the influence of vegetative characteristics, specifically visual obstruction, and the presence of predators on snowshoe hare abundances across the Apostle Islands. We conducted fecal pellet surveys to estimate hare abundance, measured …

Territorial Behavior Of The Ozark Zigzag Salamander, Plethodon Angusticlavius, Altered By Mode Of Predator Cue And Sex Of Intruder, Sarah E. Heimbach

MSU Graduate Theses

Territorial defense in many species must be balanced with trade-offs in activities such as reproduction and predator avoidance. Adjusting behavior based on current assessments of predation risk and the cost of maintaining or gaining a territory is one way that individuals can balance trade-offs to maximize fitness. I conducted two experiments to determine how Ozark zigzag salamanders, Plethodon angusticlavius, adjust their territorial behavior-based predation risk. First, I tested whether male and female territorial intruders changed their competitive behavior according to whether predation risk is assessed via unimodal (chemical) or multimodal (chemical + physical) cues. Females and males responded differently to …

Comparing Feeding Accuracy Between High And Low Predation Trinidad Guppies, Lydia J. Bonnell

Honors College Theses

Efficient feeding accuracy could increase an organism’s survival. Although local adaptation in Trinidad guppies is common, the effects on accuracy are unknown. Guppies were wild caught in 2015 and 2017, filmed while capturing prey. Accuracy wasn’t different within samples but differed across samples, possibly due to the prey types used.

Ecosystem Functional Consequences Of Body Size Variation In An Apex Predator (Ambystoma Jeffersonianum), David Samuel Smith

Online Theses and Dissertations

Biodiversity is often emphasized at the species level where each species is assigned a mean functional trait value. However, populations within a species, and individuals within a population, often exhibit considerable intraspecific functional variation. Therefore, instead of focusing on species’ mean trait values, we must incorporate intraspecific variation when considering species’ ecological roles and conservation values. The primary objective of this study was to determine the effects of variation in body size (a functional trait in many aquatic taxa) in an apex predator on ecosystem functioning. We sought to characterize trophic cascades initiated by larval populations of Ambystoma jeffersonianum that …

Eternal Enemies, Or Incidental Encounters? Structure And Patterns Of Interspecific Killing In Carnivora, Tor G. Bertin

Theses and Dissertations

Lethal interactions between carnivorans (interspecific killing) may influence their population dynamics, behavior, and other important aspects of their ecology. In this study, I expand upon previous research on the broad-scale patterns of interspecific killing in Carnivora (Palomares & Caro 1999, Donadio & Buskirk 2006) with a greatly expanded dataset (inclusion of scat and stomach data and more intensive sampling of the literature), and suggest avenues for future research. While like previous studies, I found a positive effect of relative body size between killer species and killed species on the likelihood of forming a killing interaction, I failed to find evidence …

The Nesting Ecology Of Woodpeckers In The Eastern Cascades And Their Interactions With Nest Competitors And Predators, Samuel D. Cowell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Woodpeckers create nesting cavities for other birds and animals in forests. This creates dynamic interactions between both woodpeckers and these other animals. Using video cameras, we documented direct behavioral interactions between nesting woodpeckers and other animals in the Eastern Washington Cascades during the 2015 and 2016 breeding seasons. Additionally, we offered 937 students in a General Biology laboratory course to participate in this original research opportunity and described and the impact the experience had on the participants as well as the researchers.

In 2015, Western Blubebirds took over two active Black-backed Woodpecker nests by physically attacking the woodpeckers. In 2016, …

Population Dynamics Of The Threatened Staghorn Coral, Acropora Cervicornis, And The Development Of A Species-Specific Monitoring Protocol, Elizabeth Goergen

HCNSO Student Theses and Dissertations

Historically, Acropora cervicornis was found in high densities on many Caribbean, Florida, and Gulf of Mexico reefs. A disease outbreak in the late 1970s and 80s caused up to 99% loss of A. cervicornis cover at some sites, leaving populations sparsely distributed throughout its range and typically found as isolated colonies. Even though populations are depauperate causing a decrease in sexual reproduction, its fast growth rate and ability to reproduce through asexual fragmentation affords this species the potential for quick recovery and population growth. However, limited to no natural recovery has been documented. Many of these populations are poorly studied …

Competition And Predation: Interactions Between American Eels (Anguilla Rostrata) And Brook Trout (Salvelinus Fontinalis) In Virginia Mountain Streams, Jonathan Studio

Masters Theses, 2010-2019

Competition has played a large role in structuring natural communities, especially with regards to vulnerable organisms. Brook trout and American eel populations have declined in the Mid-Atlantic Region of the United States as a result of anthropogenic development around freshwater ecosystems, and thus, subsequent conservation efforts of both species have included habitat restoration. Conservation efforts have increased the co-occurrence of these predatory fish species that are known to require similar resources. The main objective of this research was to elucidate the potential for competition between brook trout and American eels through analysis of their preferred prey, diet overlap, and supplementary …

Predator Presence And Size Variation Alters Community Structure Through Multiple Trophic Cascades, Robin Baker, Howard Whiteman Ph.D.

Murray State Theses and Dissertations

Predation plays a crucial role in shaping community structure and can initiate trophic cascades that can alter abundances across adjacent trophic levels. Recent research has suggested that variation among individual predators may have stronger effects on ecological dynamics than previously appreciated. Intraspecific variation within predators could lead to differential levels of top-down control with implications for trophic cascade strength. In this experiment, we manipulated the body size variation of predatory mole salamanders (Ambystoma talpoideum) within experimental mesocosms and monitored a suite of abiotic and biotic response variables. We predicted that predator populations with increased body size variation would …

Life On The Edge: Risk Of Predation Drives Selection Of Habitat And Survival Of Neonates In Endangered Sierra Nevada Bighorn Sheep, Shannon Forshee

Graduate Student Theses, Dissertations, & Professional Papers

Long-term viability of endangered populations requires development of effective management strategies that target the population vital rate with the highest potential to influence population trajectories. When adult survival is high and stable, juvenile recruitment is the vital rate with the greatest potential to improve population trajectories. For my thesis I examined how lactating Sierra Nevada Bighorn sheep (Ovis Canadensis sierra) balance forage and predation risk during the neonatal period. I first identified resource selection strategies employed by lactating females to promote survival of neonates and then determined the primary factors affecting survival of neonates. I found lactating females selected for …

The Evolution Of Fear Ecology: A Fruit Fly (Drosophila Melanogaster) Perspective, Itachi Mills

Theses

Several mechanisms underlie how evolutionary lineages respond to predation pressures or predation risk. Further mechanisms link evolutionary predation responses to how animals forage, or find mates. However, gaps remain in our understanding about how predation and foraging interact in an evolutionary context.

In my first chapter, I elaborate on how predation and foraging relate in to one another in ecological, evolutionary and behavioral contexts. I start out with an overview of fear ecology. Then, I outline how trade-offs influence the evolution of morphological, chemical and behavioral responses to predation. I further elaborate on how these trade-offs influence reproduction. Finally, I …

Nutritional Plasticity In Gray Treefrogs: Interactions Between Competition And Predation Threat, Troy C. Neptune, Sarah S. Bouchard

Undergraduate Honors Thesis Projects

Anurans utilize digestive tradeoffs to best survive in their environment, often in response to competition and predation pressure. In some larval anurans, intraspecific competition induces longer guts, providing a digestive advantage under limiting resources. However, predation threat can induce deeper tails and associated shorter guts in larvae. The purpose of this study was to describe nutritionally plastic responses of larval eastern gray treefrogs, Hyla versicolor, reared with simultaneous environmental stressors: predation and competition. Specifically, we asked if larval guts lengthen to increase digestive efficiency or will tail morphology change to better evade predators? H. versicolor larvae were reared in …

The Role Of Habitat Management In Shaping Predation, Animal Color, And Gene Flow In A Metapopulation Of Florida Scrub Lizards (Sceloporus Woodi), Richard William Orton

Electronic Theses and Dissertations

Anthropogenic disturbance is known to affect biological diversity at the community, species, and genetic levels. Habitat fragmentation, in particular, has been shown to impact predator abundance and distribution, impede dispersal, and augment genetic drift. In small populations, which often result from habitat fragmentation, the effects of human disturbance may be disproportionately expressed. Small populations are more susceptible to selection pressures and random drift because genetic and phenotypic frequencies can become rapidly fixed, in comparison to larger populations. In turn, fixation of maladaptive alleles or morphs can accelerate extinction. For example, cryptic color polymorphism can be maintained by apostatic selection, where …

Water Loss Rates And Desiccation Tolerances For Spiders And Crickets, Matthew Zach, Kevin E. Mccluney

Honors Projects

Despite the importance of water to living organisms, access varies across the globe with high variability over space and time. Seventy-five percent of the world’s freshwater alone is ice while 99% of unfrozen freshwater is underground (Winter et al. 1998). Understanding how terrestrial species respond to water availability and compensate for water stress can provide insight to their behavior, ecology and physiology. The goal of this research was to examine the differences in the evaporative water loss rates and desiccation tolerances of Hogna carolinensis and Acheta domesticus. First, an experiment was conducted to quantify the rate of evaporative water …

The Meat-Farming Ants: Predatory Mutualism Between Melissotarsus Ants (Hymenoptera: Formicidae) And Armored Scale Insects (Hemiptera: Diaspididae), Scott A. Schneider

Doctoral Dissertations

Ant agricultural mutualisms are common, well studied, and receive attention from scientific and public spheres due to shared similarities with human agriculture (i.e. ant/fungus ‘crop farming’ and ant/insect ‘dairy farming’). They also serve as important model systems for studying many facets of mutualism. This study reveals that the repertoire of ant agriculture may also include ‘meat farming’. Predatory mutualisms occur between Melissotarsus ants and various species of armored scale insects. This dissertation employs a multi-disciplinary approach to investigate the evolutionary history and nature of ant/diaspidid mutualisms. Chapter 1 reviews the current state of knowledge regarding species composition of these associations …

Predicting Suitable Habitat Decline Of Midwestern United States Amphibians And Quantifying The Consequence Of Declines Using Pond-Breeding Salamanders, Brock Struecker

Master's Theses

With current declines of vertebrate taxa meeting or exceeding those of historic mass extinction events, there is a growing need to investigate the main drivers of declines. Amphibians are perhaps at greatest risk of global climate change and land-use changes than most other vertebrate classes and also have significant roles in ecosystem processes – combined, this creates a cause for concern. I designed a study that would investigate the effects of current and predicted climate change and land-use changes on amphibians using species distribution models and a field study to identify the potential consequences of amphibian species declines by investigating …

Factors Constraining The Reproductive Output Of Baptisia Alba Macrophylla, Ashley Morgan Hembrough

Theses and Dissertations

Baptisia alba macrophylla, a native, herbaceous perennial legume, produces inflorescences with a large number of flowers, yet matures relatively few fruits. We hypothesized that the number of seeds matured by B. alba macrophylla is maximized based on resource availability at each stage of development, but this optimal number is further compromised by extrinsic factors including pollen limitation and pre-dispersal seed predation by the weevils Apion rostrum and Tychius sordidus. To test this hypothesis, we conducted a field experiment at two sites: (i) the John English Prairie, located in Hudson, IL, and also (ii) the Sugar Grove Nature Center and Funks …

Fate Of Captive-Reared Bobwhite Quail Released In Central Kentucky, Adam Carter

Online Theses and Dissertations

The fate of pen-raised bobwhite quail (Colinus virginianus) released onto two farms (Site 1 and 2) and a reclaimed coal surface mine (Site 3) in south-central Kentucky during the summers of 2008 and 2009 was assessed. Of the 57 bobwhite quail radio-tagged and released in this study, the fate of 26 (45%) was unknown because the telemetry signal was lost and the birds could not be located. Within 34 days after release, mortality of the remaining 31 radio-tagged birds was 100%. Raptors, coyotes, and mesomammal predators were responsible for most (84%) of the identified quail mortality; accounting for the deaths …

Predators And Anti-Predator Behavior Of Wilson's Plover (Charadrius Wilsonia) On Cumberland Island, Georgia, Mary K. Strickland

Electronic Theses and Dissertations

Predation, the major cause of nest failure in birds, is an important factor when considering management and conservation plans. The predator assemblage in an ecosystem changes each year and can cause profound differences in bird nest survival rates. Shorebirds such as Wilson’s Plovers (Charadrius wilsonia) are ideal study species because they are declining and predator control is often a recommended component of management plans. Therefore the objectives of my research were to determine the predator assemblage of the southern end of the beach on Cumberland Island National Seashore, Georgia, and to determine how three variables affected the display …

Depredation Of Diamondback Terrapin (Malaclemys Terrapin) Nests In North Inlet, Sc: Nest Predator Community And The Cues Used By Raccoons To Locate Nests, Samuel Al Buzuleciu Ii

Electronic Theses and Dissertations

Predation on diamondback terrapin eggs has been studied in several terrapin populations across their broad geographic range; however, nest predators have not been studied in South Carolina. Objectives of this project were two-fold: first, identify predators of diamondback terrapin eggs in North Inlet, SC; and second, determine the source of olfactory cue(s) used by raccoons to locate terrapin nests. Terrapin nest predators were identified using a combination of camera traps, visual surveys and trackboards. Raccoons were dominant nest predators and depredated 347 of 349 (combined natural and simulated) terrapin nests during the 2013 nesting season. We identified the source of …