Ecology and Evolutionary Biology Commons^™

Phytoplankton Community And Algal Toxicity At A Recurring Bloom In Sullivan Bay, Kabetogama Lake, Minnesota, Usa, Victoria G. Christensen, Ryan P. Maki, Erin A. Stelzer, Jack E. Norlan, Eakalak Khan

Civil and Environmental Engineering and Construction Faculty Research

Kabetogama Lake in Voyageurs National Park, Minnesota, USA suffers from recurring late summer algal blooms that often contain toxin-producing cyanobacteria. Previous research identified the toxin microcystin in blooms, but we wanted to better understand how the algal and cyanobacterial community changed throughout an open water season and how changes in community structure were related to toxin production. Therefore, we sampled one recurring bloom location throughout the entire open water season. The uniqueness of this study is the absence of urban and agricultural nutrient sources, the remote location, and the collection of samples before any visible blooms were present. Through quantitative …

Testing Protocols For Surveying Captive Limulus Polyphemus Microbiomes, Fabian Leija, Sean A. Neiswenter Dr.

LSAMP Poster Presentations

Limulus polyphemus, the Atlantic horseshoe crab, is a marine arthropod that primarily resides in the shallow intertidal zone of brackish water, water where high salinity seawater meets fresh water. The ecological niche that horseshoe crabs reside in makes them an ideal animal to be placed in an aquarium touch-tank, only needing a shallow pool of water to live comfortably as well as having a tough chitin carapace that won’t be easily damaged by visitors touching them. However, the implications of these human-animal interactions are severely unexplored with limited research being conducted regarding touch-tanks. In contrast, the consequences and hygienic practices …

Plasticity In The Human Gut Microbiome Defies Evolutionary Constraints, Andres Gomez, Ashok Kumar Sharma, Elizabeth K. Mallott, Klara J. Petrzelkova, Carolyn A. Jost Robinson, Carl J. Yeoman, Franck Carbonero, Barbora Pafco, Jessica M. Rothman, Alexander Ulanov, Klara Vickova, Katherine R. Amato, Stephanie L. Schnorr, Nathaniel J. Dominy, David Modry, Angelique Todd, Manolito Torralba, Karen E. Nelson, Michael B. Burns, Ran Blekhman, Melissa Remis, Rebecca M. Stumpf, Brenda A. Wilson, H. Rex Gaskins, Paul A. Garber, Bryan A. White, Steven R. Leigh

Anthropology Faculty Research

The gut microbiome of primates, including humans, is reported to closely follow host evolutionary history, with gut microbiome composition being specific to the genetic background of its primate host. However, the comparative models used to date have mainly included a limited set of closely related primates. To further understand the forces that shape the primate gut microbiome, with reference to human populations, we expanded the comparative analysis of variation among gut microbiome compositions and their primate hosts, including 9 different primate species and 4 human groups characterized by a diverse set of subsistence patterns (n = 448 samples). The results …

Persistence And Turnover In Desert Plant Communities During A 37-Yr Period Of Land Use And Climate Change, Scott R. Abella, Ross J. Guida, Chris L. Roberts, Carrie M. Norman, James S. Holland

Life Sciences Faculty Research

Understanding long‐term changes in ecological communities during global change is a priority for 21st‐century ecology. Deserts, already at climatic extremes, are of unique interest because they are projected to be ecosystems most responsive to global change. Within a 500‐km2 landscape in the Mojave Desert, USA, we measured perennial plant communities at 100 sites three times (1979, 2008, and 2016) during 37 yr to evaluate six hypotheses of community change. These hypotheses encompassed shifts in community measures (e.g., diversity, cover) and species elevational distributions, biotic homogenization, disproportionately large change at the highest elevations, relationships between turnover and species’ responses to disturbance …

Taxonomic Features And Comparison Of The Gut Microbiome From Two Edible Fungus-Farming Termites (Macrotermes Falciger, M. Natalensis) Harvested In The Vhembe District Of Limpopo, South Africa, Stephanie L. Schnorr, Courney A. Hofman, Shandukani R. Netschifhefhe, Frances D. Duncan, Tanvi P. Honap, Julie Lesnik, Cecil M. Lewis

Anthropology Faculty Research

Background Termites are an important food resource for many human populations around the world, and are a good supply of nutrients. The fungus-farming ‘higher’ termite members of Macrotermitinae are also consumed by modern great apes and are implicated as critical dietary resources for early hominins. While the chemical nutritional composition of edible termites is well known, their microbiomes are unexplored in the context of human health. Here we sequenced the V4 region of the 16S rRNA gene of gut microbiota extracted from the whole intestinal tract of two Macrotermes sp. soldiers collected from the Limpopo region of South Africa. Results …

Heterogeneity In Surface Sensing Suggests A Division Of Labor In Pseudomonas Aeruginosa Populations, Catherine R. Armbuster, Calvin K. Lee, Jessica Parker-Gilham, Jaime De Anda, Aiguo Xia, Kun Zhao, Keiji Murakami, Boo Shan Tseng, Lucas R. Hoffman, Fan Jin, Caroline S. Harwood, Gerard Cl Wong, Matthew R. Parsek

Life Sciences Faculty Research

The second messenger signaling molecule cyclic diguanylate monophosphate (c-di-GMP) drives the transition between planktonic and biofilm growth in many bacterial species. Pseudomonas aeruginosa has two surface sensing systems that produce c-di-GMP in response to surface adherence. Current thinking in the field is that once cells attach to a surface, they uniformly respond by producing c-di-GMP. Here, we describe how the Wsp system generates heterogeneity in surface sensing, resulting in two physiologically distinct subpopulations of cells. One subpopulation has elevated c-di-GMP and produces biofilm matrix, serving as the founders of initial microcolonies. The other subpopulation has low c-di-GMP and engages in …

Muscular Apoptosis But Not Oxidative Stress Increases With Old Age In A Long-Lived Diver, The Weddell Seal, Kaitlin N. Allen, Jose Pablo Vazquez-Medina, John M. Lawler, Jo-Ann E. Mellish, Markus Horning, Allyson G. Hindle

Life Sciences Faculty Research

Seals experience repeated bouts of ischemia–reperfusion while diving, potentially exposing their tissues to increased oxidant generation and thus oxidative damage and accelerated aging. We contrasted markers of oxidative damage with antioxidant profiles across age and sex for propulsive (longissismus dorsi) and maneuvering (pectoralis) muscles of Weddell seals to determine whether previously observed morphological senescence is associated with oxidative stress. In longissismus dorsi, old (age 17–26 years) seals exhibited a nearly 2-fold increase in apoptosis over young (age 9–16 years) seals. There was no evidence of age-associated changes in lipid peroxidation or enzymatic antioxidant profiles. In pectoralis, 4-hydroxynonenal-Lys (4-HNE-Lys) levels increased …

Ecological Effects Of Fear: How Spatiotemporal Heterogeneity In Predation Risk Influences Mule Deer Access To Forage In A Sky‐Island System, Christopher Lowrey, Kathleen M. Longshore, David M. Choate, Jyoteshwar R. Nagol, Joseph Sexton, Daniel Thompson

Life Sciences Faculty Research

Forage availability and predation risk interact to affect habitat use of ungulates across many biomes. Within sky‐island habitats of the Mojave Desert, increased availability of diverse forage and cover may provide ungulates with unique opportunities to extend nutrient uptake and/or to mitigate predation risk. We addressed whether habitat use and foraging patterns of female mule deer (Odocoileus hemionus) responded to normalized difference vegetation index (NDVI), NDVI rate of change (green‐up), or the occurrence of cougars (Puma concolor). Female mule deer used available green‐up primarily in spring, although growing vegetation was available during other seasons. Mule deer and cougar shared similar …

Assessing Minimal-Input Restoration Strategies For Desert Soil And Vegetation Restoration, Audrey Jean Rader

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mojave and Sonoran Deserts have been negatively impacted by anthropogenic disturbances. Considering that these ecosystems may recover on millennial timescales, research has shown that restoration techniques can be fairly successful in initiating long-term recovery processes in these sensitive environments. However, uncertainty remains as to which techniques are effective in different circumstances, such as in different climates or across different soil properties, and which techniques may best avoid unintended consequences, such as facilitating non-native plants. To reduce fugitive dust as a human health hazard, increase soil stability, and enhance wildlife habitat, further work is necessary to develop restoration techniques for …

Beyond Genetics: Addressing Activity In Microbial Ecology, Scott Christopher Thomas

UNLV Theses, Dissertations, Professional Papers, and Capstones

The field of microbial ecology is on the cusp of another revolution, one that uses synergy to address the limitations of previous studies. My dissertation is representative of the new era of research to come, through combining the latest technological advances with established classical methods to provide a more complete understanding of microbial ecosystems. In my first study, I evaluate the conservation of central carbon metabolic pathways and activity along a temperature and diversity gradient (60-95 ℃) through the use of 16S rRNA gene amplicon data, metagenome sequencing, and position-specific 13C-labeled metabolite probing. In my second study, I provide the …

Effects Of Ecological Restoration Techniques In Glen Canyon National Recreation Area, Simone Ka-Voka Jackson

UNLV Theses, Dissertations, Professional Papers, and Capstones

A better understanding of key ecological restoration techniques can inform land management in the Southwest on restoration options for areas infested by invasive grasses that can pose threats to ecosystems, from changes in nutrient cycling to altered fire regimes. In the semi-arid desert of Glen Canyon National Recreation Area (GLCA), several exotic grasses pose risks to local ecosystems: Saccharum ravennae, a relatively new invasive perennial grass, and Bromus rubens and Bromus tectorum, widespread annual grasses. In this study, multiple ecological restoration techniques were implemented to assess their effects on native and nonnative vegetation on sites invaded by the non-native grasses …

Effects Of Disturbance And Restoration Treatment On Fertile Islands In Lake Mead National Recreation Area, Camille Traylor

UNLV Theses, Dissertations, Professional Papers, and Capstones

Disturbances by humans are one of the main drivers of change in contemporary desert ecosystems. Restoration treatments such as topsoil application and outplanting can be implemented in response to disturbances in order to maintain soil stability and a diverse plant community. Fertile islands - nutrient enriched areas beneath perennial shrubs - are fundamental features of deserts that can facilitate annual plant growth. A major uncertainty in desert ecology is how much time is required for fertile islands and nurse plant effects (the facilitation of one plant by another) to develop below maturing perennial plants. By studying naturally recruited perennial plants …

Long-Term Monitoring Of Rare Gypsum Communities In The Eastern Mojave Desert: A Study In Science And Art, Tiffany Jane-Marie Pereira

UNLV Theses, Dissertations, Professional Papers, and Capstones

For land managers, reliable estimates of soil seed banks, and more specifically, change in seed banks over time, provide insight into the restoration and regeneration potential of the landscape, site history and disturbance mapping, and, invasive and rare plant management. To understand the intricacies of desert soil seed banks in relation to aboveground vegetation change, my research evaluated long-term change in soil seed banks, fertile islands, and plant communities of conservation-priority gypsum rare plant habitat of the eastern Mojave Desert. Research found significant spatial and temporal differences in seed bank composition and density over an 11-year period; however, the gypsum …

Hawaiian Picture‐Winged Drosophila Exhibit Adaptive Population Divergence Along A Narrow Climatic Gradient On Hawaii Island, Jon Eldon, M. Renee Bellinger, Donald K. Price

Life Sciences Faculty Research

1. Anthropogenic influences on global processes and climatic conditions are increasingly affecting ecosystems throughout the world. 2. Hawaii Island’s native ecosystems are well studied and local long‐term climatic trends well documented, making these ecosystems ideal for evaluating how native taxa may respond to a warming environment. 3.This study documents adaptive divergence of populations of a Hawaiian picture‐winged Drosophila, D. sproati, that are separated by only 7 km and 365 m in elevation. 4.Representative laboratory populations show divergent behavioral and physiological responses to an experimental low‐intensity increase in ambient temperature during maturation. The significant interaction of source population by temperature treatment …

Justice Served Fresh: Associations Between Food Insecurity, Community Gardening, And Property Value, Micajah Daniels, Courtney Coughenour Ph.D

McNair Poster Presentations

Numerous stakeholders in Nevada have used a variety of efforts to combat the growth of food insecurity facing Nevadans. The purpose of this research project is to understand the association between food insecurity, community gardens, and property value. Following the wealth of scholarship on these topics and data collected from community garden agencies in Southern Nevada, the research questions for this project include: (1) Where are community gardens located in SNV? (2) What efforts community gardens agencies are doing to address food insecurity (most interested in their efforts using community gardens)? (3) What are the perceptions of supports and barriers …

Cougar Dispersal And Natal Homing In A Desert Environment, David M. Choate, Kathleen M. Longshore, Daniel B. Thompson

Life Sciences Faculty Research

We present a review of cougar dispersal literature and the first evidence of natural (i.e., unmanipulated) homing behavior by a dispersing male cougar (Puma concolor) that sustained severe injuries crossing the northern Mojave Desert. Based on Global Positioning System and ground tracking data, the male traveled a total distance of 981.1 km at 5.03 km/d, including 170.31 km from the Desert National Wildlife Refuge to the northwestern Grand Canyon, where he sustained severe injuries. The interkill interval increased from 7.1 ± 2.7 d while he was in his natal range to 17.5 ± 4.9 d during dispersal. While homing, the …

Genomic Inference Of The Metabolism And Evolution Of The Archaeal Phylum Aigarchaeota, Zheng-Shuang Hua, Yan-Ni Qu, Qiyun Zhu, En-Min Zhou, Yan-Ling Qi, Yi-Rui Yin, Yang-Zhi Rao, Ye Tian, Yu-Xian Li, Lan Liu, Cindy J. Castelle, Brian P. Hedlund, Wen-Sheng Shu, Rob Knight, Wen-Jun Li

Life Sciences Faculty Research

Microbes of the phylum Aigarchaeota are widely distributed in geothermal environments, but their physiological and ecological roles are poorly understood. Here we analyze six Aigarchaeota metagenomic bins from two circumneutral hot springs in Tengchong, China, to reveal that they are either strict or facultative anaerobes, and most are chemolithotrophs that can perform sulfide oxidation. Applying comparative genomics to the Thaumarchaeota and Aigarchaeota, we find that they both originated from thermal habitats, sharing 1154 genes with their common ancestor. Horizontal gene transfer played a crucial role in shaping genetic diversity of Aigarchaeota and led to functional partitioning and ecological divergence among …

Larval-Ant Interactions In The Mojave Desert: Communication Brings Us Together, Alicia Mellor

UNLV Theses, Dissertations, Professional Papers, and Capstones

Butterflies are a diverse and essential group of pollinators whose abundance is predominantly determined by growth and survival of their larvae. In the family Lycaenidae, many species participate in a larval-ant mutualism where ants feed on nutrient-rich nectar produced by larvae and, in turn, protect those larvae from predators. Emerging evidence indicates larval scent in the form of cuticular hydrocarbons (CHCs), not nectar production, drives this interaction. This study takes two approaches to investigate CHCs as the driver behind the larval-ant mutualism in three butterfly species native to southern Nevada: Euphilotes bernardino martini (Martin’s blue), Brephidium exilis (western pygmy blue), …

Emerging Infectious Disease And The Imperiled Relict Leopard Frog, Anthony Wayne Waddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

The disease chytridiomycosis, caused by the aquatic fungal pathogen Batrachochytrium dendrobatidis (Bd), has emerged as a major contributing factor for worldwide amphibian declines. Although relatively recently described, the impacts from the disease this pathogen causes have been definitively tied to amphibian declines, including some that occurred decades ago. In some cases, declines of individual species occurred with little documentation and are thus poorly understood. The relict leopard frog (Rana onca = Lithobates onca) has experienced such a decline and by the latter part of the 20th century only occurred in two general areas in southern Nevada. Recent research has found …

Acute Salivary Steroid Hormone Responses During Coalitional And Dyadic Competitions In Hong Kong Juvenile Children, Timothy Mchale

UNLV Theses, Dissertations, Professional Papers, and Capstones

A large body of research links testosterone and cortisol responses to competition during adulthood. Little psychoneuroendocrine research has explored salivary steroid hormone responses to competition during middle childhood. This project investigated the relationship between acute salivary steroid hormone change, performance, competitor type, and outcome effects in three different field studies, while controlling for Body Mass Index (BMI) and pubertal development, in a population of ethnically Chinese, Hong Kong juvenile children, 8-11 years of age. The relative dynamics of salivary steroid change were assessed during a 1) coalitional physical competition (soccer) in boys, 2) a non-physical mixed-sex coalitional competition (math contest), …

Living On The Edge: Assessing The Effects Of Catastrophic Fire On Plants Utilized By Two Endemic Subspecies Of Spring Mountains Butterflies, Charles Ryan Herrmann

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the past few decades there has been an increase in catastrophic, high-intensity, large-scale wildfires globally due to the combination of climate warming with more than a century of fire suppression policy. One region that has been drastically affected is the Western United States, as there has been an increase in ‘mega-fires’ in the past few decades. The 2013 Carpenter 1 Fire in the Spring Mountains, Nevada was the largest fire in recorded history in these mountains, spreading out over 11,137 hectares. Catastrophic fire like the Carpenter 1 Fire can have potentially devastating effects on endemic species inhabiting refugia on …

Behavioral Paleoecology Of Lower Cambrian Deposit Foragers: Reinterpreting Looping And Meandering Traces Using Optimal Foraging Theory And Quantitative Analysis, Zachary Andrew Jensen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The early Cambrian was a period of transition during which the seafloor environment was changing from a microbial-mat-dominated environment to a bioturbation-dominated environment. The result was a patchy landscape of variable food resources for foraging burrowers to exploit. Looping trace fossils, such Psammichnites gigas and Taphrhelminthopsis nelsoni, appear in strata worldwide during this transitional period, and the ecological niche they filled is a subject of debate among ichnologists. The objectives of this study are (1) to determine the foraging strategies preserved by looping traces through the application of optimal foraging theory and quantitative analysis, and (2) use those results to …

Thermal And Developmental Ecology Of Pupfish, Cyprinodon, Alexander Jones

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pupfish from the genus Cyprinodon are among the most endangered groups of fishes on the planet, with nearly 40% of species being threatened with extinction. These pupfishes are often assumed to be the most temperature tolerant of all fish, coping with temperatures as low as 0 °C and as high as 44 °C. However, conflicting data exist and certain measures of thermal tolerance are not markedly higher in pupfish compared to common game fish. Pupfish egg production and growth has been known to be hampered at temperatures well below what they apparently experience in nature. I addressed why eggs fail …

Sexual Determination From Frontal Sinus Analysis In A Subadult Population Using Archival Radiographic Records, Erica Crosta

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this study is to use the improved imaging capability of cone-beam computerized tomography (CBCT) to investigate the development and sexual dimorphism of the frontal sinus and surrounding supraorbital region in the subadult population of urban Southern Nevada. CBCT radiographs were obtained from the UNLV School of Dental Medicine archival dental records. Five hundred and fifty six of these radiographs were reviewed for the study. Two hundred and sixteen patients (92 males, 124 females) between the ages of 7 and 20 years were included based on inclusion/exclusion criteria. Samples were categorized into 3 subadult age groups for analysis: …

Behavioral Reactions To Emotional And Physical Infidelity: An Evolutionary Perspective, Mandy Walsh Walsh

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis examined the effects of sex and type of partner infidelity, including both physical (i.e., sexually involved with another person) and emotional (i.e., emotionally involved with another person) infidelity, on mate abandonment behaviors. Previous research has demonstrated sex differences in emotional responses to infidelity, where men react more negatively to physical infidelity and women react more negatively to emotional infidelity. While various studies have investigated perceived behavioral reactions using imagined scenarios, this study expands current research by utilizing actual retrospective reports. It was hypothesized that males would engage in significantly more mate abandonment behaviors after experiencing a physical infidelity, …

Incomplete Denitrification In Thermus Species, Chrisabelle Mefferd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Members the bacterial genus Thermus have been shown to be incomplete denitrifiers, terminating with nitrite or nitrous oxide (N2O). However, the ability to carry out denitrification and the evolution of nitrogen oxide reductase genes in Thermus remains poorly understood. This study tests the hypothesis that incomplete denitrification is common in Thermus and seeks to uncover patterns in the evolution of denitrification pathways in Thermus. Denitrification capacity was determined in a collection of 25 strains representing ten species of Thermus and phylogenetic analysis was performed to determine whether denitrification genes evolved horizontally in Thermus. No strains in this study reduced nitrate …

Water Source Partitioning For Shrubland Transpiration In A Mixed Phreatophytic Plant Community, Amanda Jean Wagner

UNLV Theses, Dissertations, Professional Papers, and Capstones

Groundwater in the basins of east central Nevada (Great Basin Desert, NV) has been permitted for export to southern Nevada. These basins are also vulnerable to changes in climate that could lead to declining recharge. Any decline in groundwater levels no matter the driving force could significantly impact phreatophytes (deep rooted shrubs), which utilize water from both the vadose zone and the capillary fringe to meet plant water needs, to support growth, and for overall health. A reduction in groundwater due to these forces could have a significant impact on the decoupling of phreatophytes from what is normally a reliable …

Status And Management Of Non-Native Plant Invasion In Three Of The Largest National Parks In The United States, Scott R. Abella, Nicholas A. Fisichelli, Sarah M. Schmid, Teague M. Embrey, Debra Hughson, Jane Cipra

Life Sciences Faculty Research

Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens), an ‘ecosystem engineer’ that alters fire regimes, was most widespread, …

Rapidly Restoring Biological Soil Crusts And Ecosystem Functions In A Severely Disturbed Desert Ecosystem, Lindsay P. Chiquoine, Scott R. Abella, Matthew A. Bowker

Life Sciences Faculty Research

Restoring biological soil crusts (biocrusts) in degraded drylands can contribute to recovery of ecosystem functions that have global implications, including erosion resistance and nutrient cycling. To examine techniques for restoring biocrusts, we conducted a replicated, factorial experiment on recently abandoned road surfaces by applying biocrust inoculation (salvaged and stored dry for two years), salvaged topsoil, an abiotic soil amendment (wood shavings), and planting of a dominant perennial shrub (Ambrosia dumosa). Eighteen months after treatments, we measured biocrust abundance and species composition, soil chlorophyll a content and fertility, and soil resistance to erosion. Biocrust addition significantly accelerated biocrust recovery on disturbed …

Physiology And Genetics Of Starvation-Selected Drosophila Melanogaster, Christopher Michael Hardy

UNLV Theses, Dissertations, Professional Papers, and Capstones

In nature, organisms have evolved to survive in stressful environments. This has driven organisms to adopt a wide range of unique adaptations. Investigating the mechanistic basis of these adaptations is an important tool for discovery that has led to major advances in science and medicine.

We study how organisms survive life without food, or starvational stress. Environmental stressors have shaped the quantity and quality of food sources across the globe. This has led to vast differences in the ability of some organisms to tolerate starvation over others. Many researchers have used Drosophila melanogaster as a model to study global patterns …