Life Sciences 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 …

Metabolic Scaling Of Aquatic Macroinvertebrates, Jacob Woelber

Honors Thesis

The common assumption in regard to metabolic rate scaling with body size is the 3/4 law, which predicts a scaling exponent of 0.75 between log metabolic rate and log body size. Supporting evidence exists for this theory on a large, general scale. However, factors such as temperature, predation, and environment can cause the scaling exponent to deviate from 0.75. This paper takes a closer look at the effects of temperature and predation on metabolic rates via oxygen consumption in freshwater macroinvertebrate populations. To do this, 24 tanks were filled with water to allow natural populations of macroinvertebrates (predominantly Chironomidae) to …

Habitat Selection By Desert Carnivores: How Water, Intraguild Predation, And Prey Impact Animal Space Use, Nadine A. Pershyn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Across North America large carnivores have lost nearly half of their historic range, creating openings for smaller (< 15 kg) carnivores to take over their ecological roles. Coyotes (Canis latrans) have seen a significant range expansion, including into arid deserts. It was believed that the addition of artificial water sources by humans allowed coyotes to expand into desert ecosystems where they were previously unable to survive. The kit fox (Vulpes macrotis) is a small, desert-adapted carnivore with declining populations that faces threats from coyotes of intraguild predation. This is when carnivores compete over the same prey, and the larger carnivore (intraguild predator) kills the smaller carnivore (intraguild …

The Potential For Top-Down Control Of The Corallivorous Gastropod Coralliophila Galea And Its Effect On Coral Reef Ecosystems, Tanya Y. Kamerman

All HCAS Student Capstones, Theses, and Dissertations

Corallivores are understood to be ecologically important. However, their effects on reef ecosystems are difficult to distinguish from the multiple anthropogenic stressors currently affecting reefs. The corallivorous muricid snail, Coralliophila galea, has been documented to have a strong negative impact on Caribbean coral reefs, including curtailing reef recovery following other stressors. Although the basic biology of C. galea is relatively well understood, the limited information on its predators prevents a complete understanding of predator-snail-coral relationships, which limits proper protection and conservation of coral reef ecosystems. To determine the impact predators of C. galea have on coral reef ecosystems, I assessed …

The Influence Of Predation Environment On The Sensory Ecology Of Brachyrhaphis Rhabdophora, Alexandra Grace Duffy

Theses and Dissertations

Across the animal kingdom, predation is a ubiquitous and omnipresent selective agent for a variety of traits. I aimed to address gaps in our knowledge pertaining to how predation shapes animal behavior. Many species of fish naturally occur in drainages that differ in the density of predators and exhibit obvious population divergence, making them ideal study organisms to investigate predator-driven behavioral evolution. In Chapter 1, I conducted a systematic review of the literature. The purpose of this review was to determine if predation acted as a stronger or weaker selective agent on particular behavioral traits (e.g., foraging, mating, antipredator etc.) …

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 …

Recruitment, Cost Indexes, And Management Of Box-Nesting Wood Ducks In South Carolina And North Carolina, Emily Miller

All Theses

The wood duck (Aix sponsa) has experienced one of the most significant declines and recoveries among species of North American waterfowl (Anatidae). With enactment of the Migratory Bird Treaty Act (1918) and installation of hundreds of thousands of artificial nest structures for this cavity-nesting species in North America, wood duck populations have recovered and remain a sustainable harvested resource. However, long-term research on box-nesting wood ducks conducted at the Savannah River Ecology Laboratory, Aiken, South Carolina, has revealed uncertainty as to whether recruitment rates of yearling females from natal box-nesting populations are self-sustaining without immigration of hens from …

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 …

Efficacy Of Predator Exclusion Methods And Id Of Nest Predators For Interior Least Terns And Piping Plovers At Off-Channel Nesting Sites Along The Central Platte River, Nebraska, Usa, Kaley Keldsen

Biology Theses, Dissertations, and Student Creative Activity

Nest predation is a major cause of failed shorebird reproduction. Management to increase reproductive success and survival of nesting interior least terns (Sterna antillarum athalassos; hereafter, least tern), and piping plovers (Charadrius melodus) that nest along the Central Platte River focuses on constructing and managing off-channel nesting habitats that are protected and monitored for least tern and piping plover productivity (i.e., nesting success and fledging success). However, nest and brood fates of unknown outcome, failed to unknown causes, or failed due to predation have been high for both species. These uncertainties lead to the investigation of avian and mammalian predator …

Phenotypic Diversity And Costs Of Early Hatching In Lizards, Zachary Winstead

USF Tampa Graduate Theses and Dissertations

Early hatching is a form of environmentally cued hatching in which embryos can emerge early to improve chances of survival and is considered a means of antipredator defense. Early hatching as a response to predation has been well documented in amphibians, but its prevalence among other animal groups is unknown. Moreover, any trade-offs between early hatching and other traits, and thus survival, are not well understood. There is anecdotal evidence that lizards exhibit early hatching behavior, but quantitative evidence is limited to one study. In the present study, I tested for the presence of early hatching in six species of …

The Effects Of Interspecific Competition And Predation On Survival Of Neonate Mule Deer, Daniel W. Sallee

Theses and Dissertations

Mule deer (Odocoileus hemionus) populations are influenced by multiple factors, including interspecific competition and predation. Interspecific competition can affect resource acquisition and survival through altering space use and access to preferred habitat. Mule deer in some areas alter space use in the presence of competing species, including bison (Bison bison), cattle (Box taurus), elk (Cervus canadensis), and feral horses (Equus caballus), however the influence of competition on survival of mule deer during specific life history stages, such as birthing and rearing of neonates, is largely unknown. In addition to competition, predation can influence mule deer populations and even limit population …

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 …

Evidence Of Non-Strike Induced Chemosensory Searching By Eastern Copperheads (Agkistrodon Contortrix) During Cicada Predation, Henderson Cyrenius Gull

Online Theses and Dissertations

New evidence of active foraging by eastern copperheads, Agkistrodon contortrix, contradicts its description as an envenomation-reliant ambush predator. Evidence of active foraging through non-strike induced chemosensory searching (NSICS) was previously found in cottonmouths (A. piscivorus) but could not be replicated with A. contortrix in later experiments. I observed foraging methods similar to non-strike induced chemoreception when specifically predating upon cicada nymphs during seasonal emergences. I hypothesized that A. contortrix actively forage using chemoreception without envenomation, and that tongue flick rates would be higher during foraging behaviors than during non-predatory or resting behaviors. Behavior of twelve A. contortrix were filmed at …

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 …

Quantifying The Ecological Drivers And Impacts Of Parrotfish Predation On Caribbean Corals Communities, Hannah Sima Rempel

Master's Theses

Parrotfishes (Scarinae) are dominant Caribbean herbivores that play an important role in reducing coral-algae competition by grazing algae; yet some species are also occasional coral predators (corallivores) and thereby can have direct negative impacts on coral growth and survivorship. There is concern that parrotfish corallivory may contribute to substantial long-term declines in targeted coral species, particularly in areas with a high biomass of parrotfishes and low cover of corals. However, the capacity of target coral species to heal from parrotfish predation and the ecological drivers of corallivory are poorly understood.

In Chapter 1, we examined the patterns of coral healing …

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 …

The Effects Of Leaf Litter On Predation Cue Response In Gray Tree Frog Tadpoles, Hyla Versicolor, Dani Mccauley

Undergraduate Distinction Papers

Plant litter is an important resource for consumers, particularly in freshwater environments where it influences the development processes of larval amphibians. Leaf litter alters the physiochemical environment by lowering dissolved oxygen while increasing nitrogen, tannin, and phenolic acid levels. Many anuran species show plastic responses to the threat of predation. This is communicated through a kairomone when a tadpole is consumed, allowing surviving tadpoles to alter their behavior and morphology to evade predators. The purpose of this study was to analyze the interactive effects of leaf litter and predation on gray treefrog tadpoles (Hyla versicolor). The chemical output of the …

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.

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 …

Density And Distribution Of Piscivorous Fishes In The Sacramento – San Joaquin Delta, Christopher M. Loomis

Cal Poly Humboldt theses and projects

Predatory fishes, including numerous introduced species, are common to the Sacramento – San Joaquin Delta, but abundance data for most species is insufficient to determine the Delta-wide distribution and ecological impacts of these species. Predatory fishes (e.g. Striped Bass, Largemouth Bass have long been suspected of contributing to the decline of native species, including salmonids, but data has been insufficient to investigate this hypothesis. In this study, I present a novel method to assess predator fish populations across the southern Delta using DIDSON acoustic cameras and analyze the environmental associations that form the landscape and fine-scale distribution of predatory fishes. …

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 …

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 …