Life Sciences Commons^™

Seed Bank Composition Within Two Sagebrush Communities: A Comparison Of Drought, Microsite, And Aboveground Community Effects, Allison Marie Nunes

Cal Poly Humboldt theses and projects

Soil seed banks are critical biodiversity repositories for many dryland plant communities. Understanding how environmental factors alter seed bank composition can provide valuable information on ecological processes within a community and be useful for creating land management strategies. Using the seedling emergence method, I characterized the seed bank of two adjacent dryland plant communities that vary in dominant sagebrush species, structure, and function. Specifically, within an Artemisia arbuscula dominated community and Artemisia cana dominated community, I assessed the influence of three environmental factors on each seed bank: experimentally imposed drought, shrub microsites (compared to interspaces), and aboveground vegetation. Within the …

Do Beaver Dam Analogues Act As Passage Barriers To Juvenile Coho Salmon And Juvenile Steelhead Trout?, Christopher G. O'Keefe

Cal Poly Humboldt theses and projects

In the Pacific Northwest, the human-caused reduction of quality and quantity of freshwater rearing habitat is a limiting factor for Pacific Salmon populations. Beaver dam analogues (BDAs) increase suitable rearing habitat for juvenile salmonids and promote the restoration of critical stream processes. Installing BDAs is an increasingly popular alternative to more intensive restoration techniques, due to the relatively low cost and effort required to install BDA structures. However, widespread installation of BDAs has been slowed by regulatory agencies’ concerns that BDAs may impede fish passage. Few studies have empirically assessed the extent to which BDAs impede fish passage, and no …

Satellite-Based Phenology Analysis In Evaluating The Response Of Puerto Rico And The United States Virgin Islands' Tropical Forests To The 2017 Hurricanes, Melissa Collin

Cal Poly Humboldt theses and projects

The functionality of tropical forest ecosystems and their productivity is highly related to the timing of phenological events. Understanding forest responses to major climate events is crucial for predicting the potential impacts of climate change. This research utilized Landsat satellite data and ground-based Forest Inventory and Analysis (FIA) plot data to investigate the dynamics of Puerto Rico and the U.S. Virgin Islands’ (PRVI) tropical forests after two major hurricanes in 2017. Analyzing these two datasets allowed for validation of the remote sensing methodology with field data and for the investigation of whether this is an appropriate approach for estimating forest …

Response Of Coastal Ichthyoplankton Assemblages Off Northern California To Seasonal Oceanographic And Climate Variability, Blair M. Winnacott

Cal Poly Humboldt theses and projects

This study analyzed samples collected along the Trinidad Head Line (41°N) to characterize variability in the ichthyoplankton assemblage in coastal waters off northern California from late 2007 through 2019, a period during which a major marine heatwave (MHW; late 2014-16) strongly perturbed the ecosystem. I augmented visual identification with genetic techniques to resolve the species composition of visually cryptic larval rockfishes (Sebastes spp.). While taxonomic composition off northern California was largely similar to studies off Oregon and Washington, and cross-shelf structure and seasonal patterns in species’ abundance were generally consistent with the distribution and phenology of parental stocks, interannual …

Effect Of Whole Fruit Based Anthocyanins On Systemic Inflammation, Oxidative Stress, And Waist Circumference In Women, Anastasiya Yudinova

Cal Poly Humboldt theses and projects

Cardiometabolic disease (CMD) remains the leading cause of death nationally. Intra-abdominal fat (IAF) is one of the primary risk factors for CMD. Women are particularly vulnerable to developing CMD due to hormonal changes during and after menopause that increase IAF. Excess IAF has deleterious effects on the body, increasing systemic inflammation and oxidative stress, leading to CMD. This systematic review and meta-analyses examined current research related to consumption of whole foods high in anthocyanins, their impact on oxidative stress and inflammation, and the medium and amount of anthocyanin delivery that yields the most benefits to women at risk for CMD. …

Effects Of Prescribed Fire On Drought Resistance And Recovery In Mixed Conifer Forests Of Lassen Volcanic National Park, California, Zachary J. Wenderott

Cal Poly Humboldt theses and projects

Forests throughout much of the western United States are experiencing increasing climatic variability, often resulting in decreased forest productivity and elevated likelihood of tree mortality. Severe drought, such California’s recent 2012-2015 drought, are projected to increase in intensity, frequency, and severity throughout much of this region in coming years. Forest management has long relied on prescribed fire and mechanical thinning to reduce fuel loads and ameliorate potential fire hazards. These treatments may also have the ability to reduce stand density, alleviate competitive pressures, and allow residual trees access to critical resources during periods of extreme stress. Utilizing a long-term National …

Wingate Muscular Power Test Reference Values For Active Healthy Adults Ages 19-29: Normative Data And Differences Between Sex, Levi Basist

Cal Poly Humboldt theses and projects

The Wingate Muscular Power Test (WMPT) has existed for several decades and to this day is considered the gold standard for evaluating an individual’s muscular power. However, the utility of this test is predicated on having accurate and relevant normative data with which to compare individual results. At present, the existing literature on this subject is either several decades old and/or inclusive of only specific subject groups (i.e. men only or sport-specific athletes). This study presents WMPT normative values for active healthy adults ages 19-29, separated by sex. The sample consisted of 330 active healthy volunteers (186 men and 144 …

The Politics Of Biomass Energy In California: How External Benefits Are Used To Support An Economically Marginal Sector, Dana L. Dysthe

Cal Poly Humboldt theses and projects

Since the 1990s, there has been a decline in biomass energy generation in California. In order to promote state governmental policies aiming to increase biomass energy generation in California, the sector has been linked to a series of external benefits that biomass energy purportedly brings. Through document analysis, semi-structured interviews, and participant observation, five distinct external benefits were identified that have been used to promote the biomass energy sector. These external benefits are: renewable energy generation, air quality improvements, promotion of forest restoration and fuel removal projects, disposal of wood waste from agricultural and forestry sectors, and rural economic development. …

Noninvasive Genetic Sampling With A Bayesian Spatial Capture-Recapture Analysis To Estimate Abundance Of Roosevelt Elk (Cervus Canadensis Roosevelti), Makenzie Henk

Cal Poly Humboldt theses and projects

Determining abundance of Roosevelt elk (Cervus canadensis roosevelti) in central Humboldt County, California has presented a unique challenge to wildlife managers due to the dense forest habitat and the animals’ elusive behavior. As the elk population has increased, so has human-wildlife conflict, and wildlife agencies need efficient and repeatable methods for determining abundance to inform management decisions. Traditional monitoring methods such as helicopter surveys are ineffective due to low sighting probability and strong behavioral responses to the aircraft. They also often lead to biased sex ratios when the distribution of males and females varies across the landscape. Non-invasive …

Grit And Mindset - Unrelated To Performance In A Motor Learning Task, Jacob Smith

Cal Poly Humboldt theses and projects

Objective Research has shown grit and mindset can be improved, but no known research has investigated the effect of learning a new skill on grit and growth mindset. While grit and mindset seem to predict success in education and success, it is also not clear if initial grit or mindset have an effect on motor skill acquisition. The purposes of this research are to investigate if grit and growth mindset are predictors of learning a new skill and if learning a new skill leads to improvement in grit and growth mindset. Methods 14 students enrolled in a motor learning course …

Comparison Of Standard And Environmental Dna Methods For Estimating Chinook Salmon Smolt Abundance In The Klamath River, California, Doyle Joseph Coyne

Cal Poly Humboldt theses and projects

Evaluating abundance of juvenile salmonids is critical to conservation and management. Current abundance estimation involves use of rotary screw traps and mark-recapture studies. Use of environmental DNA (eDNA) in water samples offers a noninvasive and less expensive approach that may potentially improve or eventually replace traditional monitoring. Here I evaluate the utility of eDNA to predict weekly abundance estimates of outmigrating Chinook salmon (Oncorhynchus tshawytscha) smolts in the Klamath River, California. A total of 15 water samples were collected per week over the 17-week smolt outmigration in both 2019 and 2020. Chinook salmon eDNA concentration in each water …

Estrogen Disruption Of Hypothalamic Neural Activity, Princess Dickson

Cal Poly Humboldt theses and projects

The brain is highly dependent on the endocrine system for proper neurodevelopment, as it plays a key role in many biological processes. Bisphenol A is a chemical found in plastics that has the potential to mimic the effects of Estrogen in the body, at least weakly. People interact with plastic that contains BPA regularly, and people are at risk for exposure even before being born. The abundance of BPA, along with other exogenous estrogens, makes examining the relationship between early exposure and changes in brain activity imperative. The current study aims to establish a relationship between disrupted estrogen function and …

Building Habitat Suitability Models To Examine Distribution Shifts For The Black-Headed Grosbeak, Hairy Woodpecker, And Yellow-Rumped Warbler Due To Drought, Fire, And Bark Beetle Infestation In The Pacific Northwest, Holli Nicole Pruhsmeier

Cal Poly Humboldt theses and projects

Spatial models that describe species distributions are valuable in determining how environmental impacts, such as drought, fire, and bark beetle infestations, have shifted these distributions and guide management decisions. In this thesis, I begin by comparing the utility of two datasets by building habitat suitability models for Black-headed Grosbeak, Hairy Woodpecker, and Yellow-rumped Warbler. By combining the datasets, I created response curves that explain habitat associations I expected from each species. I expanded upon the methods section to compare pre- and post-drought data from the 2011 California multi-year drought and evaluate how the three avian species have shifted their habitat …

Effects Of A Dual-Task Paradigm On Tandem Gait Performance, Courtney Angela Perry

Cal Poly Humboldt theses and projects

In concussion management, a variety of cognitive and motor control tests, like the tandem gait, have been used for assessing the presence of a concussion injury at the sideline and through recovery. More recently, research suggests that introducing a secondary cognitive retention task during tandem gait (i.e., dual task) may provide a better assessment of concussion. The purpose of this study was to determine if a tandem gait test paired with a 6-digit retention is a valid and reliable tool. Participants completed three trials of both the single-task (ST) and dual-task (DT) tandem gait tests, and their average (MEAN) and …

Ecological And Social Drivers Of Mexican Gray Wolf (Canis Lupus Baileyi) Home Range Patterns Across Spatiotemporal Scales, Evelyn M. Lichwa

Cal Poly Humboldt theses and projects

Elucidating factors influencing home range size are fundamental relationships that can be described for any wildlife species, particularly those of conservation concern. The Mexican gray wolf (Canis lupus baileyi) is an endangered sub-species of the gray wolf whose home range patterns have not yet been studied. I estimated home range sizes for 22 Mexican wolf packs using Brownian Bridge Movement Models (95% UD). Generalized linear mixed effect models were used to evaluate environmental and social variables across four timeframes. Annual home range size was inversely related to human density and tree cover. During the denning period, home range …

Bird Abundance And Diversity In Shade Coffee And Natural Forest Kenya, Frank J. Ong'ondo

Cal Poly Humboldt theses and projects

Coffee, one of the major traded commodities in the world, has captured attention of both the international business class and conservation community due to its value as a beverage and for the habitat it can provide for wildlife. Previous work in Central Kenya has demonstrated that when cultivated with shade trees, coffee farms can host high levels of bird diversity. However, questions of how the bird community in shade coffee farms compares to those in natural forest remained unanswered. Using three visits to each of 160-point count locations in natural forest (80) and shade coffee sites (80) in Central Kenya, …

Post-Fire Effects In Chaparral And Oak Ecosystems Of Northern California, Abigail M. Jones

Cal Poly Humboldt theses and projects

The issue of wildfires, hazard fuels management, and post-fire tree mortality has become an increasingly common topic in the western United States. This thesis is composed of two studies, with the first study, Chapter 1, examining fuel treatment effectiveness and the second study, Chapter 2, striving to characterize post-fire mortality in oaks.

Prior to wildfire, fuel reduction projects may take place to decrease the likelihood of high severity fire around human infrastructure and communities. Within California’s chaparral ecosystems, common treatment types include hand-thinning, prescribed burning, mechanical mastication, and mechanical mastication followed with prescribed burning. Because chaparral has a longer historical …

Conifer Encroachment And Removal In A Northern California Oak Woodland: Influences On Ecosystem Physiology And Biodiversity, Gabriel S. Goff

Cal Poly Humboldt theses and projects

Oregon white oak (Quercus garryana) woodlands across their range are becoming increasingly threatened by encroaching Douglas-fir encroachment (Pseudotsuga menziesii) as a result of fire exclusion. Using water potential (Ψ), stomatal conductance (g_s), xylem water stable isotopes (dD), and three metrics of biodiversity, this study investigates the effects of conifer encroachment and removal at the ecosystem-scale. The study was set in an Oregon white oak woodland in northern California and compared three levels of encroachment before and after conifer removal. Findings indicate that heavily encroached stands have the least amount of water stress and gas …

Recreation, Vegetation Management, And Disease Impact Sympatric Carnivore Activity In California's East Bay Parks, Leigh J. Douglas

Cal Poly Humboldt theses and projects

East Bay Regional Park District designated over 1000 ha of protected wildland-urban interface habitat in the hills of California’s East Bay Area for invasive tree removal to reduce fire risk and restore native habitat over a 10-year period starting in 2016. From June to November 2019, 36 camera traps were deployed using a stratified two-pronged detection approach of surveying recreation and wildlife trails to assess the impact of vegetation management on the spatiotemporal distribution of sympatric carnivore species while accounting for potential impacts of human activity and proximity to development. The sampling effort resulted in 5,191 cumulative trap nights, 2,739 …

Evaluating Immaturity Risk In Young Stands Of The Serotinous Knobcone Pine (Pinus Attenuata), Katherine Marlin

Cal Poly Humboldt theses and projects

As wildfire becomes increasingly frequent, many plant populations risk local extirpation if fire recurs too soon, a problem dubbed “immaturity risk”. We studied the regeneration of a serotinous conifer species, knobcone pine (Pinus attenuata), as a function of the time between high-severity fires (6-79 years). We evaluated age, cone production, and regeneration at two burned sites in northern California, the Ranch Fire (2018) in Mendocino National Forest, and the Carr Fire (2018) in Whiskeytown National Recreation Area. We found an average of 30.5 filled seeds in closed, brown cones (42% viability of filled seeds). The bulk of the …

Influences On Conifer Drought Responses In Northern California, Wallis L. Robinson

Cal Poly Humboldt theses and projects

California is experiencing increasingly severe and prolonged droughts, which are contributing to changes in tree stress and forest mortality. Many factors affect a tree’s drought response, including competition, climate, and site and tree characteristics. Northern California provides a suitable venue to explore the effects of these factors, as it spans a variety of site conditions and includes habitat for conifers with different adaptations and requirements. This study used annual ¹³C discrimination and growth metrics to assess differences in drought resistance and resilience in conifers adapted to coastal and montane ranges at both wet and dry sites, as well as …

In-Flux: Economic And Community Adaptations Of Former Timber Mill-Towns In The American West, Cherilyn P. Ashmead

Cal Poly Humboldt theses and projects

Once built around natural resource extractive industries, rural communities’ economies are changing as the United States is transitioning away from its industrial past. While much research has focused on rural economic shifts from natural resource production toward amenity-driven economies (Morzillo et al., 2015; Winkler et al, 2007), less research has explored the economic and demographic trends in areas pursuing new modes of production. This two-part study focuses on an understudied region with historic ties to timber in dry mixed-conifer forests, much of which are under federal land management. With few natural amenity draws, the region has largely maintained production-based sectors. …

Effects Of Large Wood Restoration On Coho Salmon In A Northern California Watershed: A Before-After-Control-Impact Experiment, Natalie B. Okun

Cal Poly Humboldt theses and projects

Substantial time, money, and effort are invested in river and stream restoration projects to aid in the recovery of imperiled salmonid populations, but there is little evidence that these efforts have had lasting positive impacts on juvenile fish growth and survival. To assess the effectiveness of large woody debris (LWD) restoration, which is one of the most common restoration practices, I evaluated the growth and survival response of endangered Central California Coast coho salmon (Oncorhynchus kisutch) in a paired watershed before-after impact-control (BACI) study. To determine if LWD supplementation influenced coho salmon growth and survival, two neighboring, similar …

Evaluating The Effects Of Atlantic Menhaden Management And Environmental Change On The Northwest Atlantic Ocean Ecosystem, Maxwell T. Grezlik

Cal Poly Humboldt theses and projects

Atlantic Menhaden (Brevoortia tyrannus) is an abundant forage fish species whose management has recently shifted from using single species reference points to ecological reference points. This type of management allows for the ecological role (e.g., supporting predators) of the species to be considered when making management decisions, and is part of a growing global movement towards ecosystem-based fisheries management. One model that aided in this transition from single species to ecological reference points was the Northwest Atlantic Continental Shelf (NWACS13) model created using Ecopath with Ecosim (Buchheister et al. 2017). Here, I updated and expanded the NWACS13 model …

Resolving Variability In Size Structure In An Individual-Based Model For The North Pacific Krill, Euphausia Pacifica, Roxanne Robertson

Cal Poly Humboldt theses and projects

Individual-based models (IBMs) have emerged as a powerful tool for ecological research and are particularly well suited to studies of plankton ecology. In this thesis, I develop an IBM for the North Pacific krill, Euphausia pacifica, with the goal of replicating observed variability in size-structure in the northern California Current Ecosystem. Krill, and E. pacifica in particular, are central to the structure and function of the California Current Ecosystem. Their response to environmental forcing translates climate variability to higher trophic levels and underpins broader ecosystem responses. Recent observations indicate environmental and climate-related shifts in E. pacifica size distributions, which …

The Homology Of Sarcopterygian Gills, Kyle Orr

Cal Poly Humboldt theses and projects

Vertebrate gills may be either external (protruding from the body surface) or internal (enclosed in a chamber). Among living amphibians, external gills are found in salamander larvae and neotenes, early frog larvae, and caecilian embryos; internal gills are found only in later-stage frog larvae. Evidence for internal gills has also been found in stem tetrapods, and amphibian-like external gills have been found in some fossil temnospondyls and anthracosaurs. Gill homology among these groups and life stages has long been questioned. To address this, scanning electron microscopy, vascular casting, and paraffin sectioning were utilized to study the morphology of gills and …

Comparison Of Low-Cost Commercial Unpiloted Digital Aerial Photogrammetry To Airborne Laser Scanning Across Multiple Forest Types In California, James Edward Lamping

Cal Poly Humboldt theses and projects

Science-based forest management requires quantitative information about forest attributes traditionally collected via sampled field plots in a forest inventory program. Remote sensing tools, such as active three-dimensional (3D) Light Detection and Ranging (lidar), are increasingly utilized to supplement and even replace field-based forest inventories. However, lidar remains cost prohibitive for smaller areas and repeat measurement, often limiting its use to single acquisitions of large contiguous areas. Recent advancements in unpiloted aerial systems (UAS), digital aerial photogrammetry (DAP) and high precision global positioning systems (HPGPS) have the potential to provide low-cost time and place flexible 3D data to support forest inventory …

Use Of Redwood Basal Hollows By Bats: A Focus On The Townsend's Big-Eared Bat On The North Coast Of California, Amon Jotesh Armstrong

Cal Poly Humboldt theses and projects

Loss of roosting resources, either through disturbance or removal, negatively affects bats. For sensitive species, such as the Townsend’s big-eared bat (Corynorhinus townsendii), determining roost requirements is a critical component in conserving their habitat. Such cavity roosting bats on the North Coast of California may use hollows in large redwood trees. In this study, I examined the factors determining the use of basal tree hollows by different bat species at eight redwood forest sites in Del Norte, Humboldt, and Mendocino Counties, California. Bat guano was collected from 179 basal hollow roosts from 2017 to 2018, and guano mass …

Social Comparison Tendencies And The Reward Value Of Same-Sex Beauty Among Heterosexual Women, Melissa M. Martin Ms.

Cal Poly Humboldt theses and projects

Previous studies have suggested that heterosexual women, but not heterosexual men, find same sex beauty rewarding. This finding has been attributed to a “greater bisexual interest among heterosexual women”, but no other explanations have been offered or tested. The current study aimed to explore social comparison tendencies as a potential alternate explanation to this previously observed finding. Twenty-three heterosexual women completed a series of questionnaires designed to assess their social comparison tendencies (the social comparison orientation scale, the physical appearance comparison scale, and the intrasexual competition scale). They also completed a “pay-per-view” keypress task to measure the reward value of …

Exploring Zosterophyll Relationships Within A More Broadly Sampled Character Space: A Focus On Anatomy, Megan Nibbelink

Cal Poly Humboldt theses and projects

Important constituents of Siluro-Devonian floras, zosterophylls gave rise to the lycophytes. I explore the relationships of 18 zosterophyll species from 16 genera, maximizing sampling of anatomy. Using phylogenetic and phenetic methods, I (1) assess the influence of tree rooting, taxon sampling, and morphological vs anatomical characters on the stability of relationships; and (2) compare phylogenetic and phenetic methods in terms of relationships recovered. Phenetic analyses show sensitivity to taxon sampling and support placement of Renalia among zosterophylls, but do not provide results that are strongly congruent with those of phylogenetic analyses. Phylogenetic analyses demonstrate that taxon and character sampling significantly …