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 …

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 …

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 …

A Picture Worth A Thousand Words: Factors Influencing Disability Accommodations, Alicia E. Martin

Cal Poly Humboldt theses and projects

Because not all disabilities look the same it is difficult to label a person with disabilities just by looking at them. Given that our knowledge, attitudes, and perceptions impact how we interpret our world and our willingness to act, people, including professors, may be biased toward providing accommodations for those with easily recognizable disabilities and biased against those with non-recognizable disabilities, and this may impact the disabled person’s ability to learn. This thesis aims to address whether professors’ disability-related attitudes, perceptions of accommodation reasonableness, and willingness to provide accommodations differ when the disability is recognizable (student is pictured in a …

Macrolichen Inventory Of The Horse Mountain Botanical Area, Six Rivers National Forest, California, Usa, Sarah Norvell Conway

Cal Poly Humboldt theses and projects

Macrolichen diversity and community composition was determined for an area of high botanical interest in the Coast Ranges of Northern California – the Horse Mountain Botanical Area (HMBA) in Six Rivers National Forest. The Coast Ranges have been suggested to have high epiphytic macrolichen diversity, yet detailed site-specific macrolichen surveys are lacking for the area. Here we present comprehensive data on macrolichens of the HMBA integrated with environmental metadata at the landscape level. Twenty 0.4 ha sampling plots were positioned across the varying habitats of the HMBA and macrolichens were intensively sampled from all substrata. Out of 888 total collections, …

Food Waste Storage Gaseous Emissions Detection And Quantification Using Infrared Spectroscopy, Ryley A. Burton-Tauzer

Cal Poly Humboldt theses and projects

A growing interest in sustainable waste management and the implementation of new policies have prompted a shift towards alternative resource recovery methods for organic waste, including food waste. To effectively assess alternative food waste treatment scenarios, it is important to evaluate the life cycle impacts associated with each scenario. The storage phase of food waste, encompassing its accumulation in kitchens, and storage in bins for collection and transportation, has been overlooked as a source of greenhouse gases in previous studies. This investigation aimed to identify the greenhouse gases emitted during the initial five-day period of low-oxygen storage. An open dynamic …

Changes And Relationships Of Soil Aluminum, Organic Matter, And Hydrogen Ion Concentration With Rye Cover Crop, Arron Wilder

Cal Poly Humboldt theses and projects

Soil acidity is a common agricultural problem worldwide, as approximately 50% of all potentially arable soils are affected by pH limitations. At soil pH 3+) is considered to be the chemical form of aluminum in acid soil that hinders plant growth the most. Potentially, soil organic matter (SOM) can ameliorate the toxic effects of Al³⁺ on plants and microbes by binding with Al³⁺, thus preventing Al³⁺ (and other species of aluminum) from interacting in the rhizosphere. Increasing SOM also increases soil health indicators (i.e., microbial activity, soil water holding capacity, aggregate stability, porosity, etc.) while the …

Carnivore And Ungulate Occurrence In A Fire-Prone Region, Sara J. Moriarty-Graves

Cal Poly Humboldt theses and projects

Increasing fire size and severity in the western United States causes changes to ecosystems, species’ habitat use, and interspecific interactions. Wide-ranging carnivore and ungulate mammalian species and their interactions may be influenced by an increase in fire activity in northern California. Depending on the fire characteristics, ungulates may benefit from burned habitat due to an increase in forage availability, while carnivore species may be differentially impacted, but ultimately driven by bottom-up processes from a shift in prey availability. I used a three-step approach to estimate the single-species occupancy of four large mammal species: mountain lion (Puma concolor), coyote …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Changes In Prey Mortality: The Efects Of Multiple Predators And Temperature On California Mussels, Wesley Hull

Cal Poly Humboldt theses and projects

Organisms serve as prey to a variety of predators within natural systems, detecting threats through physical and chemical means. While predator feeding behavior is also affected by the presence of other predators, it is unclear whether differing modes of detection have similar effects on predator feeding behavior. In rocky intertidal zones in northern California, the California mussel (Mytilus californianus) is a competitively dominant foundation species consumed by a variety of predators. I quantified the individual and combined effects of ochre star (Pisaster ochraceus) and rock crab (Romaleon antennarium) predation on mussels by implementing mussel …

Estimates Of Calf Survival And Factors Influencing Roosevelt Elk Mortality In Northwestern California, Erin Nigon

Cal Poly Humboldt theses and projects

Survival of juvenile ungulates is known to be highly variable, yet it is fundamental to understanding the dynamics and trends of wildlife populations. Factors influencing calf survival are poorly understood in northwestern California where Roosevelt elk (Cervus canadensis roosevelti) are known to exist. The objectives of this study were 1) to estimate summer and annual survival rates and determine recruitment rates for Roosevelt elk calves in the area, 2) to evaluate differences in calf survival by examining the effects of individual and population level covariates on summer and annual calf survival, 3) to identify factors influencing the timing …

Exploring The Origins Of Secondary Growth – Two Lower Devonian (Emsian) Euphyllophytes From Gaspé, Canada, And Their Implications For The Evolution Of Secondary Growth, Kelly C. Pfeiler

Cal Poly Humboldt theses and projects

Secondary growth from a vascular cambium has a deep fossil record among euphyllophytes, with the earliest occurrence dated to 407 Ma. To date, Armoricaphyton and Franhueberia represent the only instances of secondary growth formally documented in the Early Devonian. Secondary growth diversified rapidly and was present in all major euphyllophyte lineages by the Middle Devonian. Here, I describe two new Early Devonian euphyllophytes exhibiting secondary growth, from the Emsian (c. 400-395 Ma) Battery Point Formation (Québec, Canada): Gmujij tetraxylopteroides gen. et sp. nov. and Perplexa praestigians gen et sp. nov. Both these plants possess mesarch actinosteles with Psilophyton-type …

Spatial And Temporal Genetic Structure Of Winter-Run Steelhead (Oncorhynchus Mykiss) Returning To The Mad River, California, Steven R. Fong

Cal Poly Humboldt theses and projects

Distinct populations of steelhead in the wild are in decline. The propagation of steelhead in hatcheries has been used to boost population numbers for recreational fisheries and for use in conservation. However, hatchery breeding practices of steelhead can result in changes in genetic structure. I investigated the genetic structure of winter-run steelhead (Oncorhynchus mykiss) returning to the Mad River, California, where a hatchery has been used enhance production for recreational fisheries since 1971. Genetic variability in Mad River steelhead was evaluated using 96 single nucleotide polymorphisms (SNPs) among 4203 individuals, including the Mad River and nearby locations, and …

Habitat Use And Prey Selection By Mountain Lions In An Altered Sagebrush Steppe Environment, Jonathan Ewanyk

Cal Poly Humboldt theses and projects

Throughout the American West there is an increasing trend of encroachment of woody vegetation on previously open sagebrush steppe habitat. The Modoc Plateau in northeastern California has not been excluded from this encroachment trend and has seen an increase in western juniper (Juniperus occidentalis) densities, likely as a result of long-term fire suppression. Mountain lions (Puma concolor) have not previously been studied on the Modoc Plateau, and there is potential for an increase in cover due to juniper encroachment to benefit the hunting behavior of lions. To better understand if the presence of cover is being …

Spatial Variability In Recruitment Of Chilipepper Rockfish (Sebastes Goodei) In The California Current System, Laura K. Solinger

Cal Poly Humboldt theses and projects

Properly describing variability in population dynamics (e.g., growth, fecundity, recruitment) is expected to improve management of important fisheries stocks (Maunder & Piner, 2014). As recruitment to most fish stocks is determined during early life history stages (Houde, 1997; Iles & Beverton, 2000), and early life history stages are influenced by oceanographic conditions (Bjorkstedt et al. 2002; Laidig, 2010), understanding how environmental stochasticity influences recruitment deviations has potential to improve estimates of stock productivity and how productivity might change over time to support more effective management. Chilipepper Rockfish (Sebastes goodei) are an important commercial species that is managed as …

Relationship Between Habitat And Barn Owl Prey Delivery Rate And Composition In A Napa Valley Vineyard Agroecosystem, Dane A. R. St. George

Cal Poly Humboldt theses and projects

The provision of habitat for natural enemies of agricultural pests is common in integrated pest management approaches globally but has rarely been examined for vertebrate predators controlling vertebrate pests. To mitigate the economic and environmental costs of treating for rodent pests, winegrape producers in Napa Valley, California, have installed nest boxes to attract barn owls (Tyto alba) to their properties, but their effectiveness to control rodent pests in vineyards has not been thoroughly tested. A rigorous estimate of the number of rodents barn owls remove from the landscape is a necessary first step, and this study aimed to …

The Effects Of Ocean Acidification And Reduced Oxygen On The Behavior And Physiology Of Juvenile Rockfish, Corianna H. Flannery

Cal Poly Humboldt theses and projects

As climate change progresses, the frequency and duration of upwelling events that bring low pH, low dissolved oxygen (DO) water to nearshore habitats are expected to increase. In addition, long-term global changes in ocean pH and DO are expected to occur within the next few decades to centuries. Locally, there have been documented reductions in near-shore pH along with the expansion of oxygen minimum zones within the California Current System. However, very few studies have investigated the potential interactive effect of these stressors on temperate reef fish. For this thesis, two sets of laboratory experiments were conducted to determine the …

Effects Of Manual And Mechanical Ammophila Arenaria Removal Techniques On Coastal Dune Plant Communities And Dune Morphology, Monique R. Silva Crossman

Cal Poly Humboldt theses and projects

The removal of invasive species as part of the restoration process can allow natives organisms to rebound. An ecosystem that incurs damages from invasive species is coastal sand dunes, which are dynamic systems. Some coastal sand dunes on the west coast of the United States have been invaded by Ammophila arenaria. The invasive grass, A. arenaria, is thought to alter and stabilize foredune morphology and reduce populations of native species. The objectives of my research are to examine the effects that manual and mechanical A. arenaria removal techniques have on coastal sand dune morphology and vegetative cover over time. …

Assessing Spatio-Temporal Patterns Of Forest Decline Across A Diverse Landscape In The Klamath Mountains Using A 28-Year Landsat Time-Series Analysis, Drew S. Bost

Cal Poly Humboldt theses and projects

Rates of tree mortality in California and the Pacific Northwest have greatly increased in recent years, driven largely by pest and pathogen outbreaks as well as the effects of hotter, warmer droughts. While there have been a multitude of regional-scale assessments of mortality and forest decline, landscape-level studies are necessary to better identify forests that are most vulnerable to decline and to anticipate future changes. This need is particularly notable in the remote and little-studied mountains of northwest California, which are renowned for their diverse, heterogeneous vegetation types. A recent observation of elevated levels of Shasta red fir (Abies …

Persistence Of Stream Restoration With Large Wood, Redwood National And State Parks, California, Diedra L. Rodriguez

Cal Poly Humboldt theses and projects

The conservation and recovery of anadromous salmonids (Oncorhynchus sp.) depend on stream restoration and protection of freshwater habitats. In-stream large wood dictates channel morphology, increases retention of terrestrial inputs such as organic matter, nutrients and sediment, and enhances the quality of fish habitat. Historic land use/land cover changes have resulted in aquatic systems devoid of large wood. Restoration by placement of large wood jams is intended to restore physical and biological processes. An important question for scientists and restoration managers, in addition to the initial effectiveness of restoration, is the persistence and fate of large wood installations. In this …

Finding Nondestructive Parameters For Root-To-Shoot Ratios In Douglas-Fir, Grand Fir, And Redwood Saplings In Northwest California For Biomass And Carbon Storage Estimates, Walter A. Kast

Cal Poly Humboldt theses and projects

ABSTRACT

FINDING NONDESTRUCTIVE PARAMETERS FOR ROOT-TO-SHOOT RATIOS IN DOUGLAS-FIR, GRAND FIR, AND REDWOOD SAPLINGS IN NORTHWEST CALIFORNIA FOR BIOMASS AND CARBON STORAGE ESTIMATES

Walter A. Kast

There is a need for better understanding of how woody biomass is allocated above and belowground and how this allocation might differ among tree species. In this field of research, investigators face challenges such as the laborious task of removing trees from the soil with destructive sampling, and the cleaning, drying, and weighing of belowground biomass (BGB). Therefore, researchers and practitioners most often rely on existing models to predict BGB from easily-measurable aboveground variables …

Multiscale Habitat Suitability Modeling For Canary Rockfish (Sebastes Pinniger) Along The Northern California Coast, Portia N. Saucedo

Cal Poly Humboldt theses and projects

Detailed spatially-explicit data of the potential habitat of commercially important rockfish species are a critical component for the purposes of marine conservation, evaluation, and planning. Predictive habitat modeling techniques are widely used to identify suitable habitat in un-surveyed regions. This study elucidates the predicted distribution of canary rockfish (Sebastes pinniger) along the largely un-surveyed northern California coast using data from visual underwater surveys and predictive terrain complexity covariates. I used Maximum Entropy (MaxEnt) modelling software to identify regions of suitable habitat for S. pinniger greater than nine cm in total length at two spatial scales. The results of …

A Comparison Of Benthic Macroinvertebrate Assemblages Between Perennial And Intermittent Headwater Streams Of The Mattole River In Northern California, Usa, Mason S. London

Cal Poly Humboldt theses and projects

Intermittent streams are common throughout the world and comprise 60% or more of total river lengths in the conterminous United States. Despite their prevalence, intermittent streams are understudied, particularly first-order headwater streams, which are vital for maintaining the function, health and biotic diversity of river networks. In June 2016, I sampled five intermittent and five perennial headwater streams in the Mattole River watershed in northwestern coastal California, USA, to compare benthic macroinvertebrate (BMI) assemblages between intermittent and perennial streams. BMI samples were collected using a 500µm mesh D-net at eight randomly located riffles along a 150-m reach, and then composited, …