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Analytic And Numerical Studies Of A Simple Model Of Attractive-Repulsive Swarms, Andrew S. Ronan

HMC Senior Theses

We study the equilibrium solutions of an integrodifferential equation used to model one-dimensional biological swarms. We assume that the motion of the swarm is governed by pairwise interactions, or a convolution in the continuous setting, and derive a continuous model from conservation laws. The steady-state solution found for the model is compactly supported and is shown to be an attractive equilibrium solution via linear perturbation theory. Numerical simulations support that the steady-state solution is attractive for all initial swarm distributions. Some initial results for the model in higher dimensions are also presented.

Modular Inheritance Of Color Pattern In Lake Malawi Cichlid Fishes, Jennifer Roscoe

Renée Crown University Honors Thesis Projects - All

This study attempts to elucidate the mechanisms that underlie the evolution of pigmentation patterns among Lake Malawi cichlids. For decades researchers have sought to provide a theoretical model of cichlid speciation based on the evolution of male nuptial patterns and female preferences, yet our understanding of how color patterns change is limited. Here, we performed exploratory statistical analyses on an F₂ hybrid population to characterize the inheritance of color traits. Specifically, we sought to uncover patterns of modularity and levels of integration among color traits. Because cichlids are sexually dimorphic we did our analyses on males and females separately. …

Ecotourism In Costa Rica: Environmental Impacts And Management, Emily Mckeone

Department of Environmental Studies: Undergraduate Student Theses

Globally we are witnessing growing environmental destruction, particularly to the natural resource bases of underdeveloped countries. If ecotourism can generate profits for local economies, while protecting and conserving the natural resource base of that community, it could be a strong alternative for numerous countries. Evidence suggests that the ecotourism industry has been expanding at a rapid rate in recent decades (Dasenbrock 2002). It is important to understand the positive and negative ecological impacts of the industry as this rapid growth rate continues.

The main objective of this study is to highlight the strengths and weaknesses of the ecotourism industry in …

An Assessment Of Stable Hydrogen-Isotope Analysis Methods To Assign Geographic Origin To Migratory Red-Tailed Hawks (Buteo Jamaicensis), Carla Marie Ahlschwede

Department of Environmental Studies: Undergraduate Student Theses

Stable-hydrogen isotopes are becoming an increasingly popular method of studying migratory birds, though sample preparation methods may affect results.  In this study I examined feathers from red-tailed hawks (Buteo jamaicensis) to determine the relationship between measure of δD due to inter-feather variation or drying methods, assessed the accuracy of results by using two birds of known-origin and estimated possible natal origins of migratory red-tailed hawks.  Two feathers per individual were taken from 81 wild hawks caught at Hitchcock Nature Center near Crescent IA and from 2 rescued red-tailed hawks, Raptor Recovery Nebraska near Eagle, NE. 119 of the …

A Study Of Habitat Selection And Fluctuating Asymmetry Of Amybstoma Tigrinum At Henderson Island Wildlife Management Area In Jefferson County Tn., Christopher Scott Ogle

Electronic Theses and Dissertations

Studies were conducted on a population of tiger salamanders, Ambystoma tigrinum, at Henderson Island Wildlife Management Area in Jefferson County, TN. Tests were conducted to locate the nonbreeding habitat of the salamanders and to detect any difference in fluctuating asymmetry (FA) between larval populations in a large, permanent pond and an ephemeral wetland. Drift fences were installed with pitfall traps at selected locations around each pond to determine nonbreeding habitat use by adults. Most adult salamanders were found using a blackberry (Rubus sp.) dominated old-field, a grassy field, and a shrub-grass mix field, which were all adjacent …

Spatial Ecology Of The Spotted Salamander Ambystoma Maculatum During The Nonbreeding Season., Dale Patrick Ledford

Electronic Theses and Dissertations

Spotted Salamanders, Ambystoma maculatum, are a widely distributed pond-breeding amphibian that spends an estimated 95% of its life in woodlands surrounding breeding ponds. Their terrestrial ecology remains poorly understood. Few studies have tracked the movement patterns of Spotted Salamanders, and they have given limited information on fine scale patterns. Studies of distribution around vernal pool environments have brought increased attention to their terrestrial ecology. To this end I tracked a sample of Passive Integrated Transponder (PIT) tagged animals with a Radio Frequency Identification Device (RFID). Quadrat-variance methods and a Poisson distribution were used to analyze spatial distribution patterns over …

Growth Of Yeast, Saccharomyces Cerevisiae, Under Hypergravity Conditions, Sapir Vangruber

Renée Crown University Honors Thesis Projects - All

The yeast, Saccharomyces cerevisiae, is a eukaryote and model organism that can be used to study how eukaryotic cells respond to hypergravity. In this experiment, six standard wild-type strains were used to determine a maximum gravitational force the yeast can withstand and still grow. Artificial gravity was generated using a centrifuge. Yeasts were found to maintain growth even at the highest artificial gravity tested, 2,114 g. An ordered deletion set of S. cerevisiae was then screened to identify genes that could not grow and withstand simulated hypergravity compared to growth under 1g conditions. Many of the strains that failed …

Ecology And Conservation Of Cougars In The Eastern Great Basin: Effects Of Urbanization, Habitat Fragmentation, And Exploitation, David C. Stoner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research was designed to investigate cougar response to urbanization, habitat fragmentation, and exploitation from behavioral, demographic, and landscape perspectives. The source-sink model has been proposed as an alternative framework for the management of exploited cougar populations. I addressed the basic question of whether cougars conform behaviorally to the predictions of the source-sink model, and consequently, the applied question of whether the model could be used for the conservation of this species. To achieve this I evaluated three scale-specific questions using radio-telemetry and hunter-harvest data collected from 1996-2010. At the subpopulation scale, I tested the hypothesis that cougars are wildland …

Relative Abundance Of Mitochondria Rich Cell Types In Threespine Stickleback: Interpopulation Differences And Salinity Effects, Dante Paolino

Honors Scholar Theses

The objective of this study is to determine whether there are evolutionary trade-offs among populations isolated to different salinities in nature with regards to mitochondria rich (MR) cell production. We expected differences among populations in MR cell abundances due to the energy requirements needed to maintain and produce these cells. Eggs from three populations of threespine stickleback (Gasterosteus aculeatus) were hatched and reared for 10 weeks and then the fish were put into one of two salinity challenges: either 0.4 ppt freshwater or 35 ppt saltwater for 13 days. The populations consisted of one isolated to freshwater, one isolated …

Natural Selection And Age-Related Variation In Morphology Of A Colonial Bird, Mary Bomberger Brown

School of Natural Resources: Dissertations, Theses, and Student Research

In May 1996, inclement weather led to the deaths of thousands of Cliff Swallows (Petrochelidon pyrrhonota) in Nebraska. Survivors had larger skeletons, shorter wings and tails, and less wing asymmetry than non-survivors. This population was followed for 10 years to study 1) whether natural selection events result in permanent microevolutionary changes, 2) if variation in climate affects the development of morphological traits, and 3) if morphological traits vary systematically with age.

Patterns in morphology exhibited by swallows following the selection event were studied by measuring yearling birds. Wing and middle tail lengths decreased, beak length and width increased, …

Multiple And Long-Term Effects Of An Introduced Predatory Crab, Catherine E. De Rivera, Edwin D. Grosholz, Gregory M. Ruiz

Environmental Science and Management Faculty Publications and Presentations

Despite the importance of invasions, few studies have explored their long-term consequences in marine systems or examined multiple types of population-level effects. Initial effects, however, may not persist over longer time frames; effects have been shown to wane in freshwater systems. We combined 14 yr of field surveys (1993 to 2006) with manipulative experiments to examine the potential for multiple effects of a nonindigenous crab Carcinus maenas on the native shore crab Hemigrapsus oregonensis over time in central California. H. oregonensis abundance was negatively correlated with C. maenas abundance. However, H. oregonensis abundance rebounded to pre-invasion levels once C. maenas …

Estimating Wildfire Potential On A Mojave Desert Landscape Using Remote Sensing And Field Sampling, Peter F. Van Linn Iii

UNLV Theses, Dissertations, Professional Papers, and Capstones

Landscape level wildfire prediction can be used to allocate wildfire resources and guide land management practices. Wildfire prediction in arid habitats in the Southwestern United States is of specific concern because of the negative ecological impacts of fire on desert habitats and the current lack of accurate fire prediction tools for such areas. This study examines the ability to predict previous fire occurrences and estimate future fire potential using satellite imagery and on the ground field survey techniques along with ignition potential data (lightning strikes and distance to roads), topographical data (elevation and aspect), and climate information (maximum and minimum …

Relationships Of Exotic Plant Invasions With Biological Soil Crust, Desert Pavement, And Soil Carbon In The Eastern Mojave Desert, Adria Decorte

UNLV Theses, Dissertations, Professional Papers, and Capstones

In a matter of 50 years, exotic annual plants have become widespread in the Mojave Desert, contributing to drastic landscape changes such as those caused by recent fires. Invasions by exotics threaten native Mojave Desert plant communities by altering community functions (e.g. fire regimes) and by reducing plant diversity. Because it is not practical, or even possible, to eradicate these exotics, developing effective prevention techniques is the key to controlling these invasions.

This thesis used a greenhouse experiment, a field experiment, and a correlational field study to examine the affect soil surface types have on the establishment of three exotic …

An Ecological Study Of Peregrine Falcons (Falco Peregrinus) At Lake Mead National Recreation Area, 2006-2010, Joseph Graham Barnes

UNLV Theses, Dissertations, Professional Papers, and Capstones

Peregrine Falcons (Falco peregrinus) represent an encouraging conservation biology success story in North America during the twentieth century. Their distribution and population size suffered major restrictions after the initiation of widespread application of the synthetic pesticide dichloro-diphenyl-trichloroethane (DDT) within the U.S. in the 1940s. The species was federally listed as endangered in the U.S. in 1969 and was then delisted in 1999 after DDT was banned in 1972. Herein, I present my ecological research of peregrines within Lake Mead National Recreation Area (LMNRA), concentrating on the years 2006-2010. This thesis is comprised of two chapters. In the first chapter, I …

Co-Development Of Biological Soil Crusts, Soil-Geomorphology, And Landscape Biogeochemistry In The Mojave Desert, Nevada, U.S.A. – Implications For Ecological Management, Amanda Jean Williams

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biological soil crusts (BSCs) are complex matrices of soil particles, mosses, lichens, and cyanobacteria that prevent erosion and influence water and energy balances, soil fertility, and vascular plant germination. The processes that form BSCs, the factors that control their distribution, and the ecosystem feedbacks that they sustain are poorly understood. This dissertation employed a novel interdisciplinary approach to address those research unknowns through investigations of the micromorphological structure, soil-geomorphic relationships, and biogeochemical feedbacks of BSCs in the Mojave Desert.

A micromorphological study of BSCs resulted in a succession model that illustrates how crust formative processes and structures change through time. …

Identification, Cloning And Fluorescent-Tagging Of Protamines Of The Flour Beetle, Tribolium Castaneum, Kristina Martimucci

Renée Crown University Honors Thesis Projects - All

The genome of eukaryotes is associated with chromosomal proteins that fold the DNA into ordered arrangements. The most abundant of these are the histones. Four of these (H2A, H2B, H3 and H4) form the nucleosomal core around which DNA is wrapped. Other proteins can associate with chromatin and fold it into higher order structures. During spermatogenesis in many organisms the standard chromatin configuration undergoes a transition to a highly condensed form in which small, highly basic proteins called protamines replace the histones. It is thought that protamine-based chromatin is more resistant to mutational damage.

Previous work by the Renkawitz-Pohl group …

A Mark–Recapture Technique For Monitoring Feral Swine Populations, Matthew M. Reidy, Tyler A. Campbell, David G. Hewitt

United States Department of Agriculture Wildlife Services: Staff Publications

Techniques to monitor populations of feral swine (Sus scrofa) relative to damage control activities are needed on rangelands. Our objectives were to describe and assess a mark–recapture technique using tetracycline hydrochloride (TH) for monitoring feral swine populations. We established bait stations at study sites in southern and central Texas. During 1 d, we replaced normal soured corn bait with bait containing TH and counted the number of feral swine that consumed bait with observers. We conducted feral swine removal using box-style traps and helicopters, at which time we collected teeth for TH analysis. In southern Texas, we estimated …

Trophic Ecology Of Burrowing Owls In Natural And Agricultural Habitats And An Analysis Of Predator Communities Using Stable Isotopes Of Carbon And Nitrogen, Kathlyn Jean Mcvey

Boise State University Theses and Dissertations

Stable isotopes of carbon and nitrogen can provide powerful tools for estimating the trophic positions of animals and determining the source or the primary producer of a food web. I used stable isotopes analysis of carbon (δ¹³C) and nitrogen (δ¹⁵N) to investigate the trophic position of burrowing owls (Athene cunicularia) in agricultural and natural habitats and trophic relationships of a community of vertebrate predators in the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA), located in southern Idaho.

Burrowing owl populations have declined across much of North America owing to loss …

Enigmatic Ornamentation Eases Male Reliance On Courtship Performance For Mating Success, Eileen Hebets, Jay A. Stafstrom, Rafael L. Rodriguez, Dustin J. Wilgers

Eileen Hebets Publications

Female preferences are frequently invoked to explain the widespread occurrence of elaborate male ornaments, yet empirical data demonstrating such preferences are sometimes equivocal or even contradictory. In the wolf spider Schizocosa stridulans, despite evidence of strong female choice, prior research has been unable to link the conspicuous sexually dimorphic foreleg ornamentation of males to their mating success. We conducted three experiments aimed at determining the function of this previously enigmatic ornamentation. Our first two experiments used males with phenotypically modified foreleg phenotypes in simple and complex mating environments in order to examine the relationship between the presence/absence of ornamentation …

Effects Of Gypsy Moth Outbreaks On North American Woodpeckers, Walter D. Koenig, Eric L. Walters, Andrew M. Liebhold

Biological Sciences Faculty Publications

We examined the effects of the introduced gypsy moth (Lymantria dispar) on seven species of North American woodpeckers by matching spatially explicit data on gypsy moth outbreaks with data on breeding and wintering populations. In general, we detected modest effects during outbreaks: during the breeding season one species, the Red-headed Woodpecker (Melanerpes erythrocephalus), increased over pre-outbreak levels, while during the winter one species, the Yellow-bellied Sapsucker (Sphyrapicus varius), increased and one, the Downy Woodpecker (Picoides pubescens), decreased from pre-outbreak levels. Responses following outbreaks were similarly variable, and in general we were unsuccessful …

The Role Of Historical And Contemporary Processes On Phylogeographic Structure And Genetic Diversity In The Northern Cardinal, Cardinalis Cardinalis, Brian T. Smith, Patricia Escalante, Blanca E. Hernandez-Banos, Adolfo G. Navarro-Siguenza, Sievert Rohwer, John Klicka

Ornithology Program (HRC)

Background

Earth history events such as climate change are believed to have played a major role in shaping patterns of genetic structure and diversity in species. However, there is a lag between the time of historical events and the collection of present-day samples that are used to infer contemporary population structure. During this lag phase contemporary processes such as dispersal or non-random mating can erase or reinforce population differences generated by historical events. In this study we evaluate the role of both historical and contemporary processes on the phylogeography of a widespread North American songbird, the Northern Cardinal, Cardinalis cardinalis …

The Importance Of Undecideds In The Evolution Vs. Creationism Debate, Seth Steinman

Senior Honors Projects

As a scientific theory, evolution has as much empirical support for its core assertions as the heliocentric universe theory or the belief that the Earth is round.  Despite a unanimous consensus in the scientific community about evolution’s validity, the General Social Survey (GSS) consistently reports that 85 percent of Americans are either undecided or do not believe in evolution.

This divide between evolutionists, led by scientists, and creationists, led by religious leaders, has enormous scientific and political implications, which include funding for basic scientific research, acting to stop global warming, and what schools should be teaching our children.

The most …

Molecular Evolution And Historical Biogeography Of New World Birds, Brian T. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Deciphering the patterns of how biodiversity has evolved across time and space has remained a fundamental objective for biologists for the last 200 years. Researchers are faced with the challenge of interpreting the complexity of evolutionary patterns that have been generated over the deep history of the Earth. The advancement of DNA sequencing technology has yielded a new and powerful genetic toolkit that has allowed biologists to address novel evolutionary questions. For my dissertation research, I used molecular genetics and a statistical framework to study the evolution and historical biogeography of birds distributed in North and South America. My dissertation …

Phylogeography Of Three Heteromyid Taxa: Insight On The Evolution Of A North American Arid Grassland Rodent Guild, Sean A. Neiswenter

UNLV Theses, Dissertations, Professional Papers, and Capstones

Revealing how communities are shaped by abiotic and biotic factors plays a central role in biogeographic and comparative phylogeographic studies. The biogeography of North American arid grasslands is explored using nuclear and mitochondrial DNA from three groups of heteromyid rodents that are broadly sympatric in aridlands across western North America. Phylogenetic and molecular clock analyses are used to estimate the timing of divergences within each group. A general pattern of late Miocene divergence and expansion of lineages in each of the groups that is coincident with the rapid expansion of arid grasslands at the time. The initial divergence is followed …

Use Of Shallow Estuarine Habitats By Nekton In The Mobile-Tensaw River Delta, Alabama, Lawrence P. Rozas, John F. Valentine, Charles Martin, Latina Steele

Biology Faculty Publications

We compared nekton density, composition, and biomass in fall 2009 and spring 2010 among three major habitat types (marsh, SAV=submerged aquatic vegetation dominated by Vallisneria americana, SNB=shallow nonvegetated bottom) commonly found throughout the Mobile-Tensaw River Delta (MTD) using 1-m2drop samplers. In the sampling design, habitat selection was based on vegetation composition. Sample locations (TR=Tensaw River, CB=Chocolatta Bay, and BC=Below Causeway) were selected based on their degree of tidal connectivity with the wider estuary (BC > TR > CB). Nekton distributional patterns varied among both locations and habitat types. Species richness was greater at BC than CB. The young of most …

Effects Of Prey-Spider Odour On Intraspecific Interactions Of Araneophagic Jumping Spiders, Fiona R. Cross, Robert R. Jackson

All Peer-Reviewed Publications

An important prediction from game theory is that the value of a resource will influence the level to which an animal is willing to escalate during conflict with conspecific rivals. Here we use this prediction as the rationale for experiments aimed at determining whether escalation decisions made by predators are influenced by the presence of preferred prey. The predators we use are adult individuals of Portia fimbriata, a jumping-spider (Salticidae) species from Queensland (Australia). P. fimbriata is known to prefer other salticid species as prey and can detect the odour of Jacksonoides queenslandicus, this being an especially common salticid species …

Causes, Extent, And Consequences Of Lead-Pellet Ingestion By Chukars (Alectoris Chukar) In Western Utah: Examining Habitat, Search Images, And Toxicology, R. Justin Bingham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lead ingestion adversely affects humans and over 130 species of wildlife. Wild chukars (Alectoris chukar) are documented to ingest lead, but the causes and consequences of this ingestion are poorly understood. The objectives of this research were to 1) examine the influence of habitat use, the hunting season, and seasonal climate on the extent and severity of lead ingestion by chukars in western Utah, 2) assess the effects of habitat use, feeding behaviors, and lead density on the causes of lead-pellet ingestion in captive and wild chukars, and 3) investigate the consequences of lead-pellet ingestion in captive chukars as a …

Temperature Increase Effects On Sagebrush Ecosystem Forbs: Experimental Evidence And Range Manager Perspectives, Hilary Louise Whitcomb

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sagebrush plant communities are among the most threatened in North America. This project had two goals: to test how increased temperature affects native and nonnative forb species common to the Western sagebrush region and to evaluate land manager beliefs about changes in their ecosystems, including those affecting forb species.

Native forbs Sphaeralcea munroana, Crepis acuminata, Linum lewisii, Penstemon palmeri, and Oenothera pallida and non-natives Erodium cicutarium and Lactuca serriola were each subjected to two treatments: experimental warming using open-top chambers and a control. Knowing how forbs used in restoration might respond to future conditions is both …

Alternative Futures For The Upper Colorado River Ecosystem: Phase Two, Temis G. Taylor

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The United States Environmental Protection Agency (2001) reports that habitat destruction is the main factor responsible for species endangerment. Trends in land use and expansion of urban areas into adjacent open space will continue to consume land and fragment or destroy habitat (U.S. Environmental Protection Agency , 2001). Studies have shown that habitat loss negatively impacts overall species abundance and reduces biodiversity (Andren, 1997; Fischer & Lindenmayer, 2007; Hansen et al., 2005; McKinney, 2002; Pimm & Raven, 2000; Sole, Alonso, & Saldafia, 2004, and others). Habitat destruction and fragmentation are believed to be core causes for biodiversity decline, although species' …

Diet, Density, And Distribution Of The Introduced Greenhouse Frog, Eleutherodactylus Planirostris, On The Island Of Hawaii, Christina A. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The greenhouse frog, Eleutherodactylus planirostris, native to Cuba and the Bahamas, was recently introduced to Hawaii. Studies from other invaded habitats suggest that it may impact Hawaiian ecosystems by consuming and potentially reducing endemic invertebrates. However, there have been no studies on the greenhouse frog in Hawaii. The first component of this study was to conduct a diet analysis. We conducted a stomach content analysis of 427 frogs from 10 study sites on the island of Hawaii. At each site, we also collected invertebrates using two different sampling methods: leaf litter collection and sticky traps to characterize available resources. …