Life Sciences Commons^™

Phylogenetic And Geographic Relationships Of Cheilostome Bryozoans In The Eastern Pacific, Hannah E. Lee

Cal Poly Humboldt theses and projects

The phylum Bryozoa is an incredibly diverse group of marine invertebrates with a widespread global distribution that is well suited for evolutionary studies but whose phylogenetic relationships are still poorly understood. Although recent studies on bryozoan taxonomies and phylogenies have increased, there is still a lack of assessment of species found at shallow water (<1 m) to intertidal depths. In this study, I aimed to expand the taxonomic sampling and assessment of the phylogenetic diversity of cheilostome bryozoans along the California coastline by utilizing mitochondrial DNA as well as inferring potential correlations between species presence and dispersal range both within and between rocky outer coast and sheltered harbor habitats. Illumina high-throughput sequencing was used to produce mitogenomes for cheilostome bryozoan samples collected off rocks from two rocky intertidal sites and off settlement panels from two harbor sites. Phylogenetic analyses generated evolutionary hypotheses of species relationships alongside geographic mapping of their distribution. This study identified 15 distinct species that represent 10 different families to form the first comprehensive phylogeny for multiple bryozoan families in California across a total range of approximately 973 km of coastline. Three genetically distinct species were found at multiple sites that are separated by a combination of rocky shores and sandy beaches, which indicates that the dispersal range of these species are not limited by geographic barriers along the coast of California. These results provide a future opportunity for further integration of this data with the phylogenies generated in this study to examine more robust evolutionary hypotheses for the phylogenetic and geographic relationships of Californian bryozoan species.

Northern Elephant Seal (Mirounga Angustirostris) Colony Establishment And Growth In The King Range National Conservation Area, California, Emma Hatton Levy

Cal Poly Humboldt theses and projects

The King Range colony is the northernmost successful and expanding breeding site for northern elephant seals (Mirounga angustirostris). To evaluate the composition and growth of this colony, I conducted systematic surveys recording counts, age classes, births, and resighting seals with individually identifiable flipper tags. The timing of life-history events (breeding, molting, and resting) of all elephant seal sex and age groups at the King Range was consistent with observations at other colonies. Colony counts during breeding and molting have increased steadily over the 4-year study period (2018-2021), and pup production has increased by 87% since the first year …

Winter Sandpiper Communities On Humboldt Bay: High-Tide Roost Use And Habitat Features That Influence Roost Site Selection, Chelsea Polevy

Cal Poly Humboldt theses and projects

Roosts, locations at which birds and other animals come together to rest and preen while remaining vigilant for predators, are a common facet of the nonbreeding biology of many shorebirds. Roosts fall on a continuum from traditional to ephemeral; traditional roosts are used consistently by the same individuals, whereas ephemeral roosts are used inconsistently and may be used only once or a few times. Studies show that roost habitat preference is the result of an individual shorebird’s attempt to optimize the costs and benefits associated with time constraints, energetic demands, and danger risks as they relate to overall fitness.

In …

Activity Patterns Of The Del Norte Salamander (Plethodon Elongatus): Monitoring Plethodontid Behavior Using Pit Tag Surveys, Sabrina Horrack

Cal Poly Humboldt theses and projects

Semi-fossorial plethodontid salamanders exhibit behavioral plasticity to avoid desiccation, retreating underground to shelter from adverse conditions such as low precipitation and high temperatures. In this study, I used passive integrated transponder (PIT) tag surveys to monitor this behavior in the Del Norte salamander (Plethodon elongatus), a small plethodontid native to northwestern California and southwestern Oregon. Within its range, a climatic gradient exists in which coastal areas experience milder temperatures and high precipitation, while inland areas tend to have colder winters, hotter summers, and lower precipitation. By monitoring the activity patterns of this species in inland and coastal areas, …

Characterizing The Relationship Of Lgl1 And Akt In Migration Of Murine Neural Stem And Progenitor Cells, Natalie Pedicino

Cal Poly Humboldt theses and projects

Asymmetric cell division and migration are critical for neural stem cell differentiation and brain development. When these processes are dysregulated in neural progenitor cells (NPCs), developmental defects and diseases like glioma can result. Lgl1 is a tumor suppressor gene that was first characterized in Drosophila neuroblasts (Strand et al., 1994). It is best known for its regulation of asymmetric cell division through its association with the Par complex. The PI3K/AKT signaling cascade is involved in cellular migration and is also regulated by Par signaling. Unpublished data from the Sprowles laboratory suggests a potential role of Lgl1 in migration and other …

Environmental Effects On Constructed Wetland Microbial Diversity And Function In The Context Of Wastewater Management, Sandrine Grandmont-Lemire

Cal Poly Humboldt theses and projects

Microbial communities play a crucial role in ecosystems, yet we know little about how microbial diversity influences ecosystem functioning. An important gap in our understanding is how environmental change affects microbial Biodiversity-Ecosystem Function relationships (BEF). These complex interactions between microbial biodiversity and ecosystem function can influence major biogeochemical processes, such as the nitrogen cycle in wetland ecosystems, which play an important role in managing wastewater. To address the effect of biodiversity on function, my study investigates the BEF relationships between microbial diversity and the function in terms of ammonia removal from wastewater at the Arcata Wastewater Treatment Facility (AWTF) both …

Assessing Soil Disturbance From Tethered Logging On Steep Slopes In Northern California, Karolyn Marie Fagundes

Cal Poly Humboldt theses and projects

The implementation of tethered harvesting allows for the expansion of mechanized logging onto steeper slopes. Recent updates to the California Forest Practice Rules have explicitly removed the slope limitation for logging equipment, provided it’s tethered. California is now witnessing the reintroduction of ground-based logging equipment on steep slopes. Previously, operating equipment on steep slopes was considered detrimental due to the potential for soil disturbance. However, tethered equipment interacts with the soil in a new way due to the use of a winch. Relatively few studies have attempted to quantify soil disturbance with this new practice. The goal of this study …

Demographic Modeling Of Conservation Strategies For The Yosemite Toad (Anaxyrus Canorus), Corrina Rebecca Kamoroff

Cal Poly Humboldt theses and projects

The Yosemite toad (Anaxyrus canorus) is an anuran species endemic to the Sierra Nevada in California that, like many amphibians globally, has suffered population declines. The documented decline in A. canorus populations across their historic range highlights the need for an effective management strategy to protect the species from future extirpation. For this study, I estimated survival rates of A. canorus using a Cormack-Jolly-Seber model populated with data from a demographic study. I then used a female-only post-birth pulse stochastic Lefkovitch matrix model using vital rates I estimated and from the literature to simulate the effect of different …

Modulation Of Polyamines To Elucidate Function Within Osteogenesis Of Mesenchymal Stromal Cells, Amin S. Cressman

Cal Poly Humboldt theses and projects

Snyder-Robinson Syndrome (SRS), an X-linked intellectual disability that arises in children, exhibits debilitating phenotypes like severe osteoporosis. These patients demonstrate an inability to produce mineralized new bone in comparison to the rate at which bone is resorbed, thus leading to weaker skeletal structure and atraumatic fractures. The known cause of SRS is due to loss-of-function mutations within the gene that encodes Spermine Synthase (SMS). Loss of SMS enzymatic activity, which catalyzes the conversion of polyamines spermidine into spermine, demonstrates an increase in the spermidine/spermine ratio in all documented cases of this disorder. The involvement of polyamines in osteogenesis is still …

Does Bisphenol-A, An Estrogen-Like Environmental Toxin, Disrupt Expression Of The Neuronal Chloride Exporter Protein During Early Brain Development?, Mayra S. Mendez

Cal Poly Humboldt theses and projects

Bisphenol A (BPA), a manufactured compound found in consumer products, is known to adversely affect early brain development by disrupting normal estrogen signaling. Recently, BPA was reported to suppress expression of a gene encoding the neuron-specific chloride ion transporter, KCC2. Human and animal studies show suppressing KCC2 can cause neuronal and behavioral hyperactivity. Therefore, some adverse effects of BPA may be due to KCC2 suppression and consequent neuronal hyperactivity. This study aimed to determine whether BPA exposure during brain development alters KCC2 expression. A secondary purpose was to evaluate whether a new transgenic zebrafish line, KCC2:mCitrine,could be used to track …

Geographic And Seasonal Variation Of Flying Squirrel Vocalizations In California, Travis A. Farwell

Cal Poly Humboldt theses and projects

Advancements in bioacoustics field studies have further elucidated spatial, temporal, and behavioral aspects of otherwise-cryptic species, as well as offering insights into species communication. The discovery of high-frequency vocalizations in North American flying squirrels in particular has allowed researchers to use ultrasonic acoustic recorders to detect these cryptic species in the wild. Investigations into vocalizations of northern flying squirrels (Glaucomys sabrinus) and southern flying squirrels (G. volans) have highlighted call type variation between species and the potential use of recorders as a tool to examine vocal activity patterns. However, high-frequency vocalizations had yet to be quantitatively …

Drought Responses Across Diverse Conifer Species, Habitats, And Competitive Gradients In Northern California, Gabriel J. Roletti

Cal Poly Humboldt theses and projects

Frequent and intense drought events are rapidly altering stand dynamics in western North American forests. Climate, competition, and site characteristics can affect the growth responses of individual trees to drought stress. The ecological and geographical diversity of northern California provides a unique opportunity to measure these responses across species, habitat types, and levels of competitive pressure. This study used dendrochronological techniques and linear mixed-effects models to assess growth responses to drought in four montane and two coastal conifer species across 54 study sites (nine sites per species and 540 trees total) in northern California. Growth was evaluated from 2002-2018 and …

The Effects Of Video Modeling And Video Feedback On Object Control Skills For Individuals With Autism Spectrum Disorder, Miguel Pelayo

Cal Poly Humboldt theses and projects

The purpose of this study was to analyze the impact of video modeling combined with immediate video feedback on the performance of object control skills used in the game of basketball for students with autism spectrum disorder (ASD). Two male students aged 12 and 13, who had a previous diagnosis of ASD and attended a middle school in Northern California were recruited for this study. A multiple baseline across behaviors single case design was used to determine the impact of the interventions on the performance of the basketball skills. Results from this study suggest that the combined use of video …

Investigating The Genetic Diversity Of Immune Genes In Non-Native Populations Of American Bullfrogs (Rana Catesbeiana), Luisa Nereyda Segovia

Cal Poly Humboldt theses and projects

The American Bullfrog (Rana catesbeiana) is a highly invasive species that has successfully colonized habitats around the world. The genetic variability of immune genes within invasive populations, like that of bullfrogs, may contribute to how resistant a population is to pathogens. The objective of this project was to characterize the genetic diversity of an immune gene in invasive bullfrog populations in California to better understand how persistent these populations might be over time. To characterize immune gene variability, I isolated exon 2 of the Major Histocompatibility Complex (MHC) Class II Beta chain gene and a neutral mitochondrial marker, …

Degradation And Nitrogen Cycling In The Context Of Biodiversity-Ecosystem Function Relationships In The Inquiline Bacterial Community Of Darlingtonia Californica, Megan Teigen

Cal Poly Humboldt theses and projects

Biodiversity-ecosystem function (BEF) research aims to explain how species and their environments interact with each other. Microbial communities engage in vital biogeochemical pathways in a variety of natural ecosystems, and yet there are large knowledge gaps about the specific metabolic pathways in which they are involved. Degradation specifically contributes to nitrogen cycling globally through the breakdown of large organic nitrogen compounds into small inorganic nitrogen that is necessary for the survival of many other organisms. In this study, I focused on the degradative function of the inquiline microbial communities found within the carnivorous pitcher plant, Darlingtonia californica. Darlingtonia grows in …

A Preliminary Study For The Development Of Free Weight Back Squat Muscular Fitness Reference Norms For Adults Aged 19-29, Eden G. Marquez

Cal Poly Humboldt theses and projects

The barbell back squat is a simple and common resistance training exercise that is used to evaluate muscular fitness. Its use as an evaluative method for muscular fitness in the general population is limited due to a lack of published reference values for this free weight exercise in the general population. This study presents reference values for the back squat muscular fitness in healthy active young adults (aged 19-29). This data is made of 399 subjects (51% male/49% female). Mean ±SD for participants in anthropometric data were 23.1±2.8 years of age, 73.0±12.9 kg weight, 170.6±9.4 cm height, and 25.0±3.4 body …

Determining Haplotype Specific X Chromosome Inactivation State And Related Epigenetic Features In Female X-Linked Genes, Ariah Dawn Mackie

Cal Poly Humboldt theses and projects

Females with heterozygous X-linked mutations are prone to pseudo-haploinsufficiency because random X chromosome inactivation (XCI) silences one of their two X chromosomes. A prior study explored the theory that reactivating the silenced healthy allele could be a treatment for pseudo-haploinsufficient females. The next step was to evaluate this approach in a clinically relevant stem cell model of the rare neurological disease CDKL5 Deficiency Disorder (CDD). It was necessary to validate X-inactivation state with respect to CDKL5 allele expression in one of these models. We explored CDKL5 allele expression in two populations of CDD female patient-derived induced pluripotent stem cells (iPSCs) …

Escherichia Coli And Salmonella Sp. In Domestic Cattle And Wild Roosevelt Elk: Fecal Pathogens At The Wildlife-Domestic Interface, Emily A. Buck

Cal Poly Humboldt theses and projects

Direct or indirect contact between domestic populations of animals and wildlife carries an inherent risk for transmission of pathogens that cause infectious disease. In Humboldt and Del Norte counties of northern California, ongoing conflict between ranchers and Roosevelt elk groups results from elk use of ranching pastures and pastures on private land. Fecal samples from elk in association with cattle, cattle, and from elk not in known association with cattle were assessed for the presence of bacteria Salmonella enterica and pathogenic Escherichia coli to assess whether association with cattle increases risk of infection for elk. Group identity (one of the …

Investigating Seed Maturation And Mortality: A Mechanism For Post-Fire Regeneration In Non-Serotinous Conifers, Madeleine A. Lopez

Cal Poly Humboldt theses and projects

Climate warming and associated dry conditions are contributing to increased fire frequency, severity, and size, for many regions in western North America. These changes in fire activity have prompted concern over the long-term persistence of some conifer species, specifically those not adapted to withstand high-severity fire. However, regeneration of non-serotinous conifer species is possible if the timing of fire occurs following seed maturation, and within a heat range that seeds can withstand, in a regenerative mechanism termed “facultative serotiny.” To address this mechanism, I determined the timing of conifer seed maturation using viability testing for four California conifer species: ponderosa …

Quantification, Isolation, Characterization, And Biogeography Of Thermoacidophilic Bacteria From Mesophilic Soils, Margaux Karp

Cal Poly Humboldt theses and projects

Many thermoacidophilic bacterial species thrive in hot springs, fumaroles, and geothermally heated soils. These habitats are globally distributed but often small in size and located distantly from similar habitats, and therefore the biogeography of thermoacidophiles may be similar to island biogeography of plants and animals. Little is known about dispersal of thermoacidophiles. In this study I aimed to quantify, isolate, and characterize thermoacidophilic bacteria from non-permissive habitats. I also used genetic approaches to compare these isolates to thermoacidophilic bacteria from permissive habitats to provide insight to their biogeography.

To determine if I could enrich thermoacidophiles from non-permissive habitats, and if …

Variation Of Larval Traits And Copper Tolerance In An Invasive Cryptic Species Complex (Watersipora: Bryozoa), Jason A. Lopiccolo

Cal Poly Humboldt theses and projects

Many factors contribute to the potential of a non-indigenous species to invade an area and become established. For bryozoan colonies of the cryptic species complex Watersipora (Neviani, 1896), this may include larval characteristics such as settlement rate, competency of metamorphosis, swimming duration, and the ability to tolerate copper, a common component in marine anti-fouling paints. Two common groups of Watersipora that occur along the California coast are W. subatra Clade A and an undescribed new species, Clade N. The goal of this research work was to discover what differences, if any, exist in the larval traits and copper tolerances of …

Drought, Tree Mortality, And Regeneration In Northen California, Sophia Lb Lemmo

Cal Poly Humboldt theses and projects

The 2012-2016 California drought was the most severe in the state’s recorded history, contributing to the death of millions of trees. While the effects of this drought on forests are relatively well studied in the central and southern Sierra Nevada, less is known about its effects on the heavily timbered and diverse forests of northern California. Through sampling 54 0.25 ha plots in northern California, this study compared tree mortality and regeneration patterns before, during, and after California’s most recent record-setting drought. This study evaluated 1) the influence of habitat and competitive covariates on mortality and regeneration trends using ridge …

A Characterization Of The Sandy Beach Surf Zone Fish Community And Their Ecology In Northern California And The Effects Of Marine Protected Areas, Katie B. Terhaar

Cal Poly Humboldt theses and projects

Historically written off as dull and homogenous, the dynamics of the sandy beach surf zone remains under studied world-wide. Northern California has been no exception to this global standard, as the sandy beach surf zone ecosystem in this region has yet to be characterized, and the effect of Marine Protected Areas (MPAs) on the fish and macroinvertebrate community fully ascertained.

Considered data-poor by local wildlife officials, commercially, recreationally and culturally important Amphistichus rhodoterus (redtail surfperch) and common Hyperprosopon ellipticum (silver surfperch) utilize the sandy beach surf zone in Northern California. Little is known about the effect of various environmental factors, …

Forecasting The Outcomes Of Managing A Rare Endemic Plant At Its Elevational Limit Under Climate Change Scenarios, Ethan Reibsome

Cal Poly Humboldt theses and projects

Lupinus constancei (Lassics lupine) is an exceptionally rare forb with a population that in 2020 consisted of 1,300 individuals located on two adjacent mountaintops in northwestern California, USA. Past work has demonstrated the species is threatened by high levels of seed predation by small mammals, which is likely the result of fire exclusion and the subsequent vegetation encroachment that both increases small mammal habitat and directly reduces suitable habitat for the species. Because of this, active management through caging of reproductive individuals to reduce seed consumption has been conducted every year since 2003. In addition, growing season temperatures have increased …

Evaluating The Use Of Barn Owl Nest Boxes For Rodent Pest Control In Winegrape Vineyards In Napa Valley, Ashley N. Hansen

Cal Poly Humboldt theses and projects

Attracting natural enemies to farms to reduce pests has long been a part of integrated pest management for insects, but knowledge of the impact of raptors on rodents and other vertebrate pests is comparatively sparse. In this study, I compared rodent prey on winegrape vineyards in Napa California with and without occupied barn owl nest boxes. We collected data before the breeding season, when hunting pressure should be light, and again when adult owls were hunting actively to feed their chicks. I used the open-hole method to quantify an index of gopher activity, and Sherman live traps to estimate the …

Foraging Behavior Of Honeybees Exposed To Mosquito Insecticides, Samantha Marie Diel

Cal Poly Humboldt theses and projects

The main aim of this study was to quantify the effects of mosquito insecticides on honey bee (Apis mellifera), foraging behavior, explicitly assessing the impacts of adult mosquito control practices on honey bee health. The extent to which honey bees are exposed to pyrethrum, pyrethrins, permethrin, and pyrethroids is unknown, as are their effects on honey bee health and vitality. This study sought to answer this question by exposing honey bees to D-Phenothrin with the addition of Piperonyl butoxide (PBO), one of many synthetic pyrethroids widely used against adult mosquitoes to control mosquito-borne diseases. Honey bees were exposed to …

Evaluating Relative Abundance, Fish Length, And Marine Protected Area Effectiveness For Four Key Rocky Reef Species Along The Northern Californian Coast, Leon Davis

Cal Poly Humboldt theses and projects

Marine protected areas (MPAs) were created with the purpose of helping conserve and restore diminished populations of marine organisms. Measuring the effectiveness of MPAs requires long-term monitoring, investigating the abundance and size distributions of the species that utilize the conservation areas, and comparing the results to neighboring reference sites that are not currently protected. In this study, observations from long-term MPA monitoring in northern California (2010-2019) were modeled with substrate, oceanographic, spatial, temporal, and body size variables to describe the variability in abundance and size of three fish groups: Black rockfish (Sebastes melanops), the Blue rockfish group (comprised …