Comparing Alternative Developmental Modes: Structure And Gene Expression In The Olfactory System Of Plethodontid Salamanders, Giuseppina S. Lanzilli

Cal Poly Humboldt theses and projects

The olfactory system of extant amphibians changes as the animal transitions from a fully aquatic to a terrestrial lifestyle at metamorphosis. Cellular morphology of the nose and expression patterns of olfactory genes in the nasal cavity have been examined for a variety of frogs and salamanders, but among plethodontid salamanders, molecular data are available only for Plethodon shermani. Using standard histology and micro-CT reconstruction, I investigated the structure of the olfactory organs of larvae, juveniles, and adults of six plethodontid species, with terrestrial, streamside, semiaquatic, and aquatic adults. The overall structure of the olfactory cavity was generally similar across …

The Effects Of Native Perennial Cover On Physiological Indicators Of Habitat Quality For Sparrows In California Coastal Prairie Rangelands, Madeleine A. Ybarra

Cal Poly Humboldt theses and projects

Prescribed grazing management can have myriad effects on wildlife, with low to moderate grazing being associated with an increased abundance of some grassland birds. Specifically, Grasshopper Sparrow (Ammodramus savannarum) and Savannah Sparrow (Passerculus sandwichensis) abundance have been shown to be positively associated with both grazing and a higher percentage of native plant cover. However, measures of abundance provide an incomplete assessment of habitat quality for birds. Physiological and morphological measurements can help indicate environmental stress in individual birds, which reveals more information about habitat quality. We measured body condition and heterophil:lymphocyte ratios to gauge avian stress …

Using Novel And Traditional Survey Techniques To Monitor Small Mammal Species In Northwestern California, Sydney Mccluskey

Cal Poly Humboldt theses and projects

Small mammal species play a critical role in forest ecosystems contributing significantly to overall forest biodiversity and ecological dynamics. Forest-dwelling species are among the most vulnerable to habitat loss and fragmentation. It is essential to develop efficient techniques for monitoring small mammal populations in forested ecosystems to inform conservation efforts and management plans; yet, monitoring small mammals in these habitats can be particularly challenging due to their size, activity patterns, and frequently nocturnal nature. In this study, I aimed to address two primary research objectives: 1) compare the effectiveness of 3 distinct camera-trap survey techniques (i.e., ground, tree, and tube) …

Evolutionary Origins Of Secondary Growth - The Periderm Perspective: Integrating Evidence From Fossils And Living Plants, Madison A.K. Lalica

Cal Poly Humboldt theses and projects

Periderm is a structural feature with roles in protection of inner plant tissues and wound healing. Knowledge of periderm occurrences in the fossil record and living lineages outside the seed plants is limited and its evolutionary origins remain poorly explored. Here, I review the known taxonomic distribution of canonical periderm (typical ontogenetic stage) and wound periderm (self-repair mechanism). To this sparse body of data I add new observations and experiments on living plant lineages and new occurrences from the fossil record. One of the latter, documented in the new early euphyllophyte species Nebuloxyla mikmaqiana, joins the oldest known periderm …

Scale And Habitat Effects On Measurement Of Streptomyces Biogeography And Biodiversity, Terilyn A. Stoflet

Cal Poly Humboldt theses and projects

Bacteria in the genus Streptomyces are detected in most soils around the world, as well as on and in seeds, plants, animals, insects and the wind. Currently, more than 700 valid species of Streptomyces have been identified worldwide. Streptomyces produce the majority of antibiotics, antivirals and antifungals, as well as important agricultural bioactive molecules due to their unique genetic capabilities. Their distinct genetic abilities allow them to produce an unlimited amount of biosynthetic gene clusters, or BGC’s. Although many compounds come from Streptomyces, scientists have not discovered the biogeographic patterns of this genus. The biogeography of Streptomyces is a …

The Effects Of Scour And Marginal Inundation On Trinity River Invertebrate Biomass And Density With Potential Implications For Juvenile Salmonid Food Resources, Benjamin King

Cal Poly Humboldt theses and projects

Regulated flow releases on the Trinity River in northern California have shifted the timing of high flows from winter to late spring and reduced their magnitude. The timing and extent of scour from high flow events and the timing and duration of marginal (bankside) habitat inundation has shifted as a result. Literature is sparse regarding the effects of these hydrologic alterations on Trinity River benthic macroinvertebrate (BMI) communities, an important food resource for juvenile salmonids. In the 2023 water year, a wet winter coupled with additional flow releases from Lewiston Dam provided the opportunity to analyze the impact of scour …

Building Detailed And Accurate Whole-Plant Concepts: A Morphometrics-Informed Reconstruction Of A Zosterophyll From The Lower Devonian Of Wyoming, Samar R. El-Abdallah

Cal Poly Humboldt theses and projects

The fragmentary state of plant fossils and the modular organization of plants make whole-plant reconstructions of fossil species desirable and feasible. Such reconstructions are key for integrating fossil species in systematic studies. The ca. 410 Ma Beartooth Butte Formation of Wyoming (USA) hosts the only rich Early Devonian plant assemblages in western North America, which fills a major gap in the phytogeography of this interval. I construct a whole-plant concept for a new zosterophyll from the Beartooth Butte Formation based on a detailed morphometric study. More than 600 fragments of the new zosterophyll were observed and 200 of those were …

Post-Fire Vegetation And Pyrodiversity Influence Breeding Abundances Of Lewis's Woodpeckers In The Eastern Cascades, Oregon, Brittany Welch

Cal Poly Humboldt theses and projects

Lewis’s woodpeckers (Melanerpes lewis) are described as "burn specialists" due to their preference for breeding in recently burned pine forests in the western US. However, despite increasing fire activity, this species experienced a 48% range-wide decline between 1968 and 2019, which raises questions about their adaptability to altered fire regimes in the region. We partnered with the Oregon Department of Fish & Wildlife to investigate how Lewis’s woodpeckers in the eastern Cascades, Oregon were influenced by post-fire habitat characteristics such as snag size, snag density, and burn severity across five wildfires that varied in fire age, size, and …

Neurocinematics And Empathy: How Cognitive Neuroscience Enhances Our Understanding Of Emotional Responses Of Film, Kira Trinity

Cal Poly Humboldt theses and projects

Cinema is a medium that is beloved around the globe since its inception over a century ago. There have been speculations on how it is that cinema works, from editing to emotional processing of the story, but only recently have we begun to explore the inner workings of cinematic impact on the brain. In this paper we will review research on cinematic impact and define cinematic editing, discuss the birth of “neurocinematics”, highlight what we have observed with regards to neuroimaging and empathy when viewing films, and speculate on how our responses to cinema may be driven by the Mirror …

The Nature And Extent Of Algal Symbiosis In Three North American Ranids, Zachary T. Vegso

Cal Poly Humboldt theses and projects

The symbiotic relationship between the chlamydomonad green alga Oophila amblystomatis and embryos of certain amphibian species is often presumed to be mutualistic. However, the existence of a mutualism has only been experimentally tested and established in two closely related ambystomatid salamanders. These experiments showed a positive correlation between intracapsular algal density and embryonic growth, survival, hatching synchrony, and hatchling body size. Oophila has been documented within egg capsules of a growing number of amphibian species, including several frogs in the family Ranidae. However, the nature and extent of this relationship remains unclear. Ranid eggs are better oxygenated than ambystomatid eggs, …

Longevity Of Prescribed Fire Effectiveness In Mixed-Evergreen Forests Of The Klamath Mountains, Kaily M. Fineran

Cal Poly Humboldt theses and projects

Prescribed fire is a common management tool used across the western United States to create wildfire-resilient ecosystems and communities. The Klamath Mountains of northern California, USA has experienced numerous, large wildfires in recent years. This is due in part to a combination of highly flammable fuels, uncharacteristic weather events, and high fuel accumulations as a result of fire exclusion and forest management practices. Within the last decade, local land management organizations and the Karuk Tribe have begun re-introducing prescribed fire in low elevation, mixed evergreen forests. While the long-term effects of fuel treatments are not well-known, these efforts provided a …

Post-Fire Persistance Of Sequoia Semperviens In A Secondary Forest: Examining Drivers Of Basal Resprouting Response, Jackson T. Carrasco

Cal Poly Humboldt theses and projects

Historically frequent-fire forest ecosystems are now facing increased size, frequency, and severity of fires attributed to climate change, intensive forest management, and fire exclusion. Understanding post-fire resilience in forest ecosystems is critical amidst escalating challenges posed by recent increases in fire activity. This study examined the basal resprouting response of coast redwood (Sequoia sempervirens) in a secondary forest two years after the CZU Lightning Complex fire on the central coast of California. Robust allometric equations were developed to quantify redwood resprout biomass and leaf area, revealing strong explanatory power for biomass equations (R² > 0.85). Probability of …

The Larval Preference Of An Invasive Bryozoan (Watersipora 'New Species') For Copper-Based Antifouling Paints, Alexander K. Strawhand

Cal Poly Humboldt theses and projects

The bryozoan Watersipora subtorquata and its cryptic congener Watersipora ‘new species’ are now globally invasive species. Previous studies have found this species complex to have a high tolerance to copper-based antifouling paints, which represent a large portion of the mitigation effort toward preventing hull fouling by invasive invertebrates. Tolerance alone, however, is unlikely to explain the full extent of Watersipora’s massive and rapid worldwide invasion success. The aim of this research was to move beyond tolerance, and test whether larvae of Watersipora ‘new species’ exhibit a preference for copper-coated settlement surfaces in both laboratory and field settings. For the laboratory …

Characterizing New Plant Fossils With Woody Growth From The Battery Point Formation Of Quebec (Canada), Emma T. Casselman

Cal Poly Humboldt theses and projects

The oldest woody growth has been recognized in several Early Devonian (ca. 410-395 Ma) euphyllophytes. Their taxonomic diversity is difficult to evaluate due to a lack of quantitative methods for comparing plants based on secondary xylem anatomy. In turn, this hinders understanding of their implications for the evolution of plant development. To develop metrics that quantify secondary xylem anatomy and allow for conclusive comparisons, I investigated extant taxa and Early Devonian fossil woody taxa. I developed multiple metrics for quantifying tracheid size as a function of position in the secondary xylem and tested them on a dataset of extant gymnosperms. …

Characterizing The Habitat Use Of Pacific Coast Feeding Group Gray Whales (Eschrichtius Robustus) And The Spatial And Temporal Variability Of Their Benthic And Planktonic Invertebrate Prey In Northern California, Robyn E. Norman

Cal Poly Humboldt theses and projects

As opportunistic foragers, the Eastern North Pacific population (~20,000) of gray whales (Eschrichtius robustus) feed on diverse benthic and planktonic invertebrates in northern Alaska foraging grounds before they undertake one of the largest yearly migrations of any mammal to breed in Baja California, Mexico. While most of the population travels to the summer foraging grounds in Alaska, a sub-group of whales (~230) called the Pacific Coast Feeding Group (PCFG) summer between British Columbia, Canada, and northern California. The diet of PCFG whales typically includes high-density and/or high-caloric prey items like mysids and diverse species of amphipods, yet a …

A Case Of Incipient Budding Speciation In The California Floristic Province, Infraspecific Divergence In Abronia Villosa, Eli J. Allen

Cal Poly Humboldt theses and projects

Physical barriers to gene flow are the traditional evidence for species divergence. Conversely, there has been increasing acknowledgment of speciation in the face of gene flow as an evolutionary process. Budding speciation involves peripheral populations adapting to local ecological conditions, thereby budding off from a widespread progenitor species. Budding speciation is distinguished by ecological divergence and is generally evidenced by asymmetrical range size and nested phylogenetic relationships of sister species. The narrow endemic Abronia villosa var. aurita is adapted to montane sandy washes adjacent to its widespread sister variety, the desert dwelling var. villosa. Here, I tested the hypothesis …

Comparative Morphology And Ultrastructure Of Olfactory Epithelia In Plethodontid Salamanders: Effect Of Life History Variation, Emily Gremling

Cal Poly Humboldt theses and projects

Many amphibian species rely on olfaction for locating prey and for social interactions during different life stages. Despite the importance of the olfactory system, research on its structure has been taxonomically limited. The most diverse family of salamanders, the Plethodontidae, has been largely excluded from research efforts to describe olfactory morphology. Although several histological studies have been conducted, no studies have yet looked at morphology at the level of ultrastructure using electron microscopy. The primary goal of my research was to examine olfactory morphology and ultrastructure in plethodontid species with a range of life history strategies, to better understand the …

Microbes: Key Constituent Of Predator Risk Cues?, Jake R. Vargas

Cal Poly Humboldt theses and projects

Chemical cues emanating from predators can play a key role in aquatic predator-prey interactions and food webs. Understanding how prey respond to these risk cues is therefore critical for understanding the direct effects of predators on prey populations and their indirect effects on communities. To respond adaptively, prey must accurately assess the risk of predation associated with perceived chemical cues, an oft-documented phenomenon. However, little is known about how cues disperse, persist, and degrade, all of which could limit the adaptive responses of prey. Using laboratory-based observations of a well-studied predator cue-induced antipredator behavior by the marine gastropod Tegula funebralis …

Evaluating The Utility Of Tracers To Characterize Environmental Dna Transport And Inform Detection Of Fishes In Small Streams, Gavin B. Bandy

Cal Poly Humboldt theses and projects

This study was motivated by the need to develop a noninvasive and highly sensitive monitoring tool for determining local occupancy of an endangered aquatic species To make inference into the occupancy of fishes within small stream sites, we developed a method to determine whether environmental DNA (eDNA) concentrations from a target species were elevated relative to a tracer, formulated to mimic eDNA and introduced at a single location. We examined patterns in the observed distribution of the tracer to account for the effects of site-specific transport processes and sampling on distributions of naturally occurring eDNA at small spatial scales (400 …

Assessing Relocation Habitats And Assisted Migration Of The Lassics Lupine, An Endangered California Serpentine-Endemic, Caitlyn M. Allchin

Cal Poly Humboldt theses and projects

The Lassics lupine, Lupinus constancei, is a serpentine species endemic to the Lassics Mountains of northern California, listed as critically imperiled and federally endangered. Increased encroachment from reduced fire intervals has led to elevated herbivory from small mammals. While deployment of exclosure cages has decreased negative impacts, diminishing snowpack from shifting climate continues to threaten the Lassics lupine. To locate possible refugia, I evaluated alternative sites for assisted migration. I built a habitat suitability model (HSM) using MaxEnt software and WorldClim variables to predict optimal habitat. I then evaluated aerial imagery, topography, and geology to identify areas for microhabitat …

Fire Severity Mediates Marten And Fisher Occurrence: Impacts Of The Dixie Fire On A Carnivore Community, Christopher James Collier

Cal Poly Humboldt theses and projects

The consumption of an astounding one million acres resulted from California’s largest single fire to date, the 2021 Dixie Fire. The social and economic losses associated with the fire were immediately apparent, but the effects on wildlife remained unknown. While previous research has suggested mixed or low severity fire may be beneficial to certain wildlife species, the responses to megafires are poorly understood for many carnivores. To better understand these responses to severe fire, I used a random sampling design stratified by burn severity to survey in and around the Dixie Fire footprint using baited camera stations. This allowed me …

Environmental Implications Of Modern Food Production: An Analysis For The Conscious Consumer, Jessica T. Coming

Cal Poly Humboldt theses and projects

This project explores the pathways by which agriculture affects the environment and determines which foods have the greatest climate, water, and land impacts. Agricultural effects on the environment are extensive, from loss of habitat and declines in regional biodiversity to disruption of global nutrient cycles and climate change. Global food production accounts for 26-34% of annual anthropogenic greenhouse gas emissions, makes up 38-46% of habitable land, and is responsible for 70% of freshwater extraction. The effect of agriculture on the environment is most significantly dictated by what type of food is being produced. Animal-based food products consistently have the highest …

Using Habitat Modeling To Locate New Populations Of Dunn's Salamander (Plethodon Dunni) Near Its Southern Geographic Range Limit, Mary A. Mackey

Cal Poly Humboldt theses and projects

Habitat suitability models were utilized to direct survey efforts for Plethodon dunni in Northern California. Two models were created, one using traditional statistical methods (GLM or Generalized Linear Modeling) and the other using a machine learning method (MaxEnt or Maximum Entropy modeling). Plots were selected from areas of agreement and disagreement between the models to carry out presence surveys. The MaxEnt model yielded better predictions than the GLM model. The two models had three variables in common (annual temperature range, precipitation of driest month, and precipitation seasonality) and predicted suitable habitat within the known range of P. dunni. The …

Pond Characteristics That Influence Oviposition Site Selection By Two Pond-Breeding Amphibians, Northern Red-Legged Frog (Rana Aurora) And Northwestern Salamander (Ambystoma Gracile), Jessica Jones

Cal Poly Humboldt theses and projects

Pond-breeding amphibians connect aquatic and terrestrial habitats through their biphasic life cycle, and understanding pond characteristics that support oviposition sites for multiple species is important for amphibian conservation. Two common amphibians in the Pacific Northwest, Northern red-legged frog (Rana aurora) and Northwestern salamander (Ambystoma gracile) often oviposit in the same pond; however, prior studies have focused on pond use by one species or the other, but not both together. I surveyed pond and oviposition site characteristics of 26 ponds in Humboldt County, CA, 10 of which were used only by R. aurora and 16 of which …

Effects Of Habitat Selection And Individual Quality On The Reproductive Success Of Barn Owls (Tyto Furcata), Jaime E. Carlino

Cal Poly Humboldt theses and projects

The hypothesis of adaptive breeding habitat selection proposes congruence between the evolved selection of habitats and fitness components such as reproductive success. However, mismatches between habitat selection and observed fitness outcomes are not unusual and can arise for multiple reasons. Variation in individual qualities of animals has also been found to affect reproduction and survival. I examined associations between barn owl nest box selection, reproductive output, and plumage characteristics previously shown to correspond to individual quality. I found that barn owls selected tall nest boxes made of wood, mounted high off the ground, and with increased proportions of grassland around …

Effect Of In Situ Experimental Heating Of Artificial Mytilus Californianus Beds On Associated Invertebrate Communities In Northern California, Claire C. Windecker

Cal Poly Humboldt theses and projects

With the continued progression of climate change, the role of foundation species as mediators of temperature stress for species living on and within them has become increasingly important. In the intertidal zone, a major foundation species is the California mussel, Mytilus californianus, which can help to limit thermal stress for species that live among aggregations of these mussels. The ability of mussels to limit thermal stress as temperatures increase, however, is still unclear. This study sought to experimentally manipulate surface temperatures of artificial mussel beds in situ to examine the effects that increased surface heating at a single site …

The Benefits Of Physical Education Programs For Students In Special Education Programs With Attention Deficit Hyperactivity Disorder, Deborah A. Mok

Cal Poly Humboldt theses and projects

Researchers have reported that exercise has had positive results on decreasing many behaviors for children with ADHD. The purpose of this study is to examine the impact of a structured physical education program for students in grades K-4 with attention deficit hyperactivity disorder (ADHD) on academic performance. This study utilized a single subject withdrawal design. Four participants attending a special day class in grades K-4 in Northern California participated in this study. Results of this study demonstrated that 30 minutes of structured physical activity had a positive impact on decreasing the number of off-task behaviors for all four of the …

Prevalence Of Batrachochytrium And Ranavirus In Southern Torrent Salamanders (Rhyacotriton Variegatus) In Northern California, Marilyn Violeta Sandoval

Cal Poly Humboldt theses and projects

Amphibian population declines around the world have been attributed in part to the emergence of deadly pathogens. However, the severity of the effects of pathogens on amphibian communities can vary by species and location. This study focuses on assessing the prevalence of Batrachochytrium dendrobatidis (Bd), Batrachochytrium salamandrivorans (Bsal), and ranaviruses in populations of southern torrent salamanders (Rhyacotriton variegatus). I also tested for association between environmental factors and the prevalence and viral load of the three pathogens in Northern California. A total of 309 skin swab samples were collected from salamanders in nine sites in …

The Interaction Of Treadmill Type And Incline Slope On Biomechanics And Muscle Activation During Human Locomotion, Rohit Kundu

Cal Poly Humboldt theses and projects

Treadmills are widely used in biomechanical research. However, variations in treadmill design and running surfaces may affect biomechanical variables such as muscle activation and impact acceleration. In addition, incline walking on treadmills leads to changes in the pattern of muscle activation, particularly at steeper inclines. Despite extensive research on the effects of running surfaces and inclines on biomechanical variables (gait, muscle activation, impact force), the impact of varying treadmill manufacturers on biomechanical variables at high inclines remains unclear. Purpose: To determine whether the type of treadmill deck influences surface electromyography (EMG) patterns and impact accelerations at high incline (20%) walking …

Seasonal Growth, Movement, And Survival Of Juvenile Coho Salmon (Oncorhynchus Kisutch) Utilizing Restored Rearing Habitat, Monica S. Tonty

Cal Poly Humboldt theses and projects

The Scott River supports the most robust population of threatened Coho Salmon Oncorhynchus kisutch remaining in the Klamath River basin. Even in the Scott River, low quality and restricted extent of juvenile rearing habitat limits the Coho Salmon population to a small fraction of historic abundance. To support persistence and recovery of Scott River Coho Salmon, the Scott River Watershed Council (SRWC) has constructed a portfolio of restoration projects to improve juvenile rearing habitat, including beaver dam analogs (BDAs). The Scott River BDAs were the first implemented anywhere in California. This study compares juvenile Coho Salmon responses associated with production …