Physical Sciences and Mathematics Commons^™

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 …

The "Upside-Down" River: Trends In Total Nitrogen, Total Phosphorus, And Microcystin Concentration In The Klamath Basin, 2010-2021, Kayla M. Fitzpatrick

Cal Poly Humboldt theses and projects

The Klamath River tends to experience impaired upstream water quality, which improves downstream. Although this consensus is accepted, an updated spatiotemporal analysis of certain water quality parameters has not been conducted since 2017. With four of the Klamath River’s dams slated for removal by the end of 2024, it is critical to have an updated assessment of current water quality conditions from which to compare conditions following dam removal. In this study, total nitrogen (TN), total phosphorus (TP), and microcystin data from 2010-2021 were analyzed to determine concentration trends from Link Dam to the Klamath River Estuary.

Concentrations of TN …

Basal Topography And Carbon Accumulation Rate Of A Rare Northern California Coastal Fen, Sarah Leidinger

Cal Poly Humboldt theses and projects

Increasingly, the importance of peatlands as biodiversity hotpots, year-round water storage features, and significant carbon sinks are being recognized. Despite this, they are one of the most vulnerable ecosystems globally. While some peatland conservation and restoration initiatives are being developed, a greater understanding of small peatlands is needed to make management decisions. This study aims to determine the timing of peat formation, peat volume, and carbon accumulation rates of the Conspicuous Scoop Fen, a small (2.1-acre) fen near Bridgeville, California (~840 m.a.s.l.). During the summers of 2022 and 2023, I collected 39 m of peat cores at 14 sampling locations. …

Habitat Selection And Habitat Use Of Gray Foxes (Urocyon Cinereoargenteus) On Trespass Cannabis Grows., Haley-Marie R. Jones

Cal Poly Humboldt theses and projects

Trespass cannabis grow sites, otherwise known as illegal cultivation sites on public lands, are extremely hazardous to the environment and can severely impact wildlife movement and behavior. Trespass grow sites are dangerous to wildlife as they negatively impact the quality of habitat and wildlife behavior through habitat modification, pesticide use, discarding of trash, and poaching on national forests. I researched gray fox habitat selection and habitat use at six different grow sites in the Klamath National Forest and Shasta-Trinity National Forest in northwestern California. I deployed GPS collars on three gray foxes at two of those grow sites and three …

Monitoring Bull Kelp (Nereocystis Leutkeana) Remotely At High Resolutions, Hannah E. Joss

Cal Poly Humboldt theses and projects

Bull kelp (Nereocystis leutkeana) is a foundational seaweed in nearshore, marine systems, traditionally supporting economically important fisheries, extracting nutrients in its vicinity, and sequestering carbon and transporting it great distances to subsidize shallow and deep-sea environments. Bull kelp is also a culturally important species for some indigenous peoples along the northeastern Pacific coastline and provides a harvestable product with growing demand. Global trends in kelp distribution show patterns of decline, and the immense loss of northern California bull kelp forests in response to climatic changes have highlighted the need for alternative sources of kelp, both for the product …

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 …

Examining The Impacts Of Beaver Dam Analogues And Groundwater Storage On Miners Creek, California, Miles Munding-Becker

Cal Poly Humboldt theses and projects

Beavers have been altering streams in North America for millions of years by impounding water behind their dams. The recent historical removal (intensely throughout the 18^th and 19^th century) of these dams altered the hydrology in low gradient streams from dynamic anastomosing streams and wet meadow complexes to incised channels with little structural diversity. Anthropogenic structures called Beaver Dam Analogues (BDAs) are used as a restorative process by mimicking natural beaver dams that can reverse channel incision, increase ponded and groundwater storage, and provide low velocity habitat for aquatic species and vegetation. A system of four original BDAs …

Evaluating Science Communication Efforts And Citizen Scientists' Knowledge Of, Attitude Toward, And Behavioral Intentions Related To The North American River Otter, Karlee D. Jewell

Cal Poly Humboldt theses and projects

Citizen Science (CS) and scientific visual, spatial, and graphic art projects have the potential to engage community members, provide opportunities for advances in scientific literacy, increase interest in science and local environmental knowledge, and elevate pro-environmental attitudes. CS depends upon public participation, and motivation for participation is varied, including participants’ desire to learn something new or contribute to science or scientific knowledge. An effective CS project will be rooted in an understanding of individuals’ motivations for participation, striving to meet those motivations, and effectively evaluating not only the scientific outputs of the project but also whether participants’ motivations are being …

Sediment Production From Forest Roads In Areas Affected By The August Complex Fire In Northern California, Zachary J. Gigone

Cal Poly Humboldt theses and projects

Wildfire activity is increasing in California and is an important factor affecting erosion rates. Landscapes recently affected by wildfire, areas that have been salvage logged after a fire, and unpaved forest roads are all major sources of sediment which can impair water quality and negatively impact many aquatic species. Therefore, this study was conducted to quantify erosion rates from native and gravel surfaced forest road segments after the August Complex fire, evaluate the impact of salvage logging activities on sediment production from roads, and understand the effect of soil burn severity on sediment production from these road segments. Finally, this …

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 …

Evidence For Middle Miocene Elevated Topography Isolating The Southern Klamath Mountains Province: A U-Pb & Lu-Hf Detrital Zircon Study Of The Weaverville Formation, Dana J. Christensen

Cal Poly Humboldt theses and projects

The Klamath Mountains Province (KMP) records a robust history of active North American margin tectonics and crustal growth through the subduction-accretion of oceanic and island-arc terranes spanning Devonian through Cretaceous time. However, preservation of Cenozoic rocks is minimal, rendering the geologic record, topography, and tectonics during this timeframe difficult to reconstruct. The only Miocene terrestrial sedimentary unit that exists in the KMP is the fluvially deposited Tertiary Weaverville Formation (Tw) that is preserved in five fault-bounded basins in the southern part of the province. This study presents new uranium-lead (U-Pb) age data and epsilon hafnium (εHf) isotopic ratios from detrital …