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 …

Using Environmental Dna Methods For Estimating Juvenile Chinook Salmon Abundance, Jacqueline Marie Bridegum

Cal Poly Humboldt theses and projects

In the Central Valley of California, stocks of Chinook Salmon are declining, and two out of the four ecotypes of Chinook Salmon within the Sacramento River system are federally listed. A monitoring network has been developed to estimate the abundances of downstream migrating Chinook Salmon smolts, but there is high uncertainty in these estimates due to low catch rates. Environmental DNA (eDNA) monitoring, which involves capture of genetic material that organisms release into their surrounding environment, has shown promise for estimating abundance of salmonids and could complement existing monitoring efforts and potentially reduce uncertainty in abundance estimates. This research project …

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 …

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 …

Modeling Current And Future Saltmarsh Distribution In Arcata Marsh, Madeline Kay Mcnerthney

Cal Poly Humboldt theses and projects

Saltmarsh habitat is vulnerable to Sea Level Rise (SLR) and requires long-term management plans for communities to continue to benefit from their ecosystem services. This study analyzed the variation of above-ground vegetation biomass throughout I Street Marsh, using multiple variables, including classified vegetative community types, elevation and remote sensing indexes comprised of both visual (Red, Green, Blue) and non-visual (Red Edge, Near Infrared) bands. Plant community types were classified using a cluster analysis, and distinguished three communities, based on dominant species: Salicornia, Spartina, and a mixed type (diverse floristic makeup, with no dominant species). Above-ground biomass was significantly higher in …

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, …

The Effects Of Post-Harvest Residue On Plantation Forest Soils And Early Growth Of Redwood And Douglas-Fir Seedlings In Humboldt County California, Robert W. Raibley

Cal Poly Humboldt theses and projects

Forest harvest residue (slash) usefulness has been up for debate among private timberland owners, public land managers, and the timber industry for decades. The disposal of slash, viewed as having low ecological value, has received considerable attention as wildfire risk has made burning it harder. In recent years, forest scientists and ecologists have recognized the importance of decaying wood and its relationship to forest growth and regeneration. At this site in Northern California, we looked at whether forest harvest residue enriches soil near slash windrows through soils coring and lab analyses, looking for primary limited nutrients nitrate (NO₃-N) …

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 …

Comparison Of Environmental Dna And Underwater Visual Count Surveys For Detecting Juvenile Coho Salmon (Oncorhynchus Kisutch) In Rivers, Jason T. Shaffer

Cal Poly Humboldt theses and projects

Environmental DNA (eDNA) has developed into a useful tool for determining the distribution of rare aquatic species, but relatively few studies have directly compared the detection probabilities of this method with other conventional survey techniques. These comparisons can inform which method may be better suited to address study objectives. In this study, the overall goal was to compare the ability of eDNA and underwater visual count (UVC) surveys to detect juvenile coho salmon (Oncorhynchus kisutch), a species of conservation concern at the southern extent of its geographic range. Specifically, I address two objectives: (1) compare the ability of …

Carnivore And Ungulate Responses To Cattle In A Grazed Forest Ecosystem, Rebecca Carniello

Cal Poly Humboldt theses and projects

Habitat disturbance, a leading threat to biological diversity, comes in many forms and can alter the behavior of wildlife and reduce the amount of suitable habitat. Livestock grazing, a form of habitat disturbance, is the most widespread influence on native ecosystems of western North America. Research on the impacts of introduced domestic herbivores on wild carnivores and ungulates varies, and the degree to which wildlife species are affected is often species-specific. I used remote trail cameras to compare the activity patterns of black bears (Ursus americanus), coyotes (Canis latrans), bobcats (Lynx rufus), mountain lions …

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 …

Estimating The Ecosystem Service Of Aleutian Cackling Goose Droppings On Pastures, Brian G. Fagundes

Cal Poly Humboldt theses and projects

The Aleutian cackling goose (Branta hutchinsii leucopareia) experienced a population low of 790 geese in 1974 and has recovered to the current estimate of 186,100 geese in 2021. Private livestock producers view geese as pasture competitors and use hazing and hunting to scare geese from private lands to adjacent public lands. I investigated if geese provide an ecosystem service via dropping fertilizing effects to improve pastures in northern California.

A greenhouse experiment was conducted from February-August 2019 at Cal Poly Humboldt, divided into two experiments: freshly sown ryegrass pasture and established plant and soil communities removed intact from …

Comparing Molecular Methods To Estimate Fish Stomach Contents And Gastric Evacuation Rates: Implications For Measuring The Impacts Of Predation On Central Valley Chinook Salmon, Cory M. Dick

Cal Poly Humboldt theses and projects

Juvenile Chinook Salmon (Oncorhynchus tshawytscha) migrating through the Sacramento – San Joaquin Delta (the Delta) in central California have higher mortality rates than salmonids migrating through other west coast estuaries. Some hypotheses for high mortality rates include entrainment into water export facilities, physical alterations of the river system, and predation. Of these factors, predation is considered the least understood but may have the largest impact. Predation from large populations of non-native piscivorous fishes in the Delta is believed to effect abundances of Central Valley Chinook salmon, however sufficient data supporting this hypothesis is scarce. In this study, I …

Factors Affecting The Production Of Berries Of The Red Huckleberry Plant In The Redwood Experimental Forest, Kagat G. Mcquillen

Cal Poly Humboldt theses and projects

Vaccinium parvifolium (red huckleberry) is a culturally and commercially valued food for different coastal tribes of northwestern California.

Today some tribes are regaining access to ancestral lands, and Indigenous researchers are working to document information about culturally significant plant species and their management to reclaim traditional ecological knowledge and restore food sovereignty.

The present study, focused on red huckleberry, Vaccinium parvifolium, took place in the ancestral territory of the Yurok Tribe, currently managed by the US Forest Service as the Redwood Experimental Forest (REF) in Klamath, CA. Geographic Information Systems-based mapping, forest ecological field data collection, and a literature …

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 …

On The Acceptance Of Urban Beavers In Martinez, California, Zane A. Eddy

Cal Poly Humboldt theses and projects

As ecosystem engineers, beavers construct complex riparian and wetland habitats that benefit many other species, including endangered salmonids. Through their landscape alterations, beavers also promote increased groundwater recharge and provide refugia during wildfires and high flow events by impounding water and allowing it to spread across the landscape. Prior to the North American colonial fur trapping campaigns, there were between 60 and 400 million beavers in North America. By the beginning of the 20th century, beavers were extirpated from many parts of the continent, however through human efforts, their population has since rebounded to between 10 and 15 million. The …

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 …

A Look At Land Cover Classification Methods In Northern California With The Use Of High Spatial Resolution Geospatial Data, Lucila Corro

Cal Poly Humboldt theses and projects

Land use and land cover (LULC) mapping plays a vital role in understanding the state of the world, showing us a visual representation of the natural and anthropogenic features covering our planet. Northern California in the United States is home to many critical habitats that provide for a variety of endemic and some threatened and engendered species, making it an area of particular concern to better understand and monitor. There is a greater need to identify specific methods for vegetation modeling in Northern California due to its unique species; to do this we examined two case studies with the following …

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 …

Assessing California Commercial Fishing Community Well-Being In The Context Of Marine Protected Area (Mpa) Formation, Samantha Cook

Cal Poly Humboldt theses and projects

Marine protected areas (MPAs)—defined geographic areas where fishing and harvesting activity is limited or restricted—have emerged as a popular marine biodiversity and climate resilience strategy worldwide. MPA monitoring efforts often follow MPA designation to help inform the adaptive management of MPAs and MPA networks. In 2012, California completed the largest statewide system of MPAs to date, consisting of 124 MPAs covering 16% of state waters. Following MPA implementation, the state initiated a long-term monitoring program (2019-2022) to help inform the 10-year MPA management review. This two-chapter thesis presents findings from a state-funded project to conduct long-term socioeconomic monitoring for human …

Using Uav And Traditional Remote Sensing Data To Detect Vegetation Vigor And Monitor Stream Morphology In A Desert Riparian Ecosystem, Jordan Bradley Adair

Cal Poly Humboldt theses and projects

Mono Lake is a terminal lake in the Eastern Sierra Nevada Mountains. The streams that feed Mono Lake support a unique desert riparian ecosystem. Rush Creek was the stream of interest for this study. The objective of this research is to determine if remotely sensed imagery can be used to determine vegetation vigor and measure stream morphologic features in a desert riparian area. The goals were to evaluate different sources of remotely sensed imagery to make these determinations. The Normalized Difference Vegetation Index (NDVI) was used to monitor vegetation vigor along Rush Creek. Google Earth imagery and UAV derived imagery …

Coho Salmon (Oncorhynchus Kisutch) Dispersal And Life History Variations Among Humboldt Bay Watersheds, Madison J. Halloran

Cal Poly Humboldt theses and projects

The decline of Coho Salmon (Oncorhynchus kisutch) in California is the result of various anthropogenic effects across the landscape, affecting all stages of their anadromous life history. Monitoring a subset of the remaining populations is essential to evaluate the success of management actions and develop new restoration projects. Defining the appropriate spatial scale for this monitoring and restoration depends on the frequency and extent of dispersal of individuals across watershed boundaries. Coho Salmon life-cycle monitoring projects in California estimate the abundance of juveniles and adults over time in selected focal watersheds. If individuals frequently enter or leave the …

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 …

Shifting Sands: Social Cues Influence The Long-Term Dynamics Of Snowy Plover Distribution, Jeremy John Pohlman Mr

Cal Poly Humboldt theses and projects

Understanding the social and physical factors that influence the temporal and spatial distribution of a species is imperative for successful management. The Western Snowy Plover (Charadrius nivosus nivosus) selects for wide-open stretches of beach; yet within large expanses of ideal habitat, plover populations tend to be aggregated. Recent evidence suggests plovers may prioritize social information over ideal physical factors alone when selecting breeding locations. I analyzed data collected on an individually marked population of Snowy Plovers in Humboldt County, California from 2001 to 2018 to evaluate the influence of physical (beach width) and social (presence of conspecifics) landscape …

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 …

Living Rivers, Cosmopolitan Activism, And Environmental Justice In The Bengal Delta, Daniel Adel

Cal Poly Humboldt theses and projects

This thesis explores the social movements and civil society activism to protect the rivers that flow through Bangladesh—the cradle and terminal delta floodplain of the transboundary Ganges, Brahmaputra, and Meghna river systems—, as well as ways to build regional cooperation and watershed democracy in South Asia. The research drew on four overarching fields of study: environmental justice, southern environmentalism, ecological nationalism, and environmental governance. These four bodies of scholarship helped address the overarching question: how are civil society organizations analyzing and responding to the water diversions and degradation of Bangladesh’s transboundary rivers? Semi-structured interviews were conducted with civil society organizations …

Species Distribution Models For Three Deep-Sea Coral And Sponge Taxa In The Southern California Bight, Nissa Kreidler

Cal Poly Humboldt theses and projects

Deep-Sea Coral and Sponge (DSCS) species are signature taxa of deep-water habitats, however understanding the ecological mechanisms that drive their geographic distributions can be difficult to uncover due to the challenges of surveying deep-water ecosystems. A recent study on benthic assemblages in Southern California revealed statistical associations between several DSCS and demersal fishes, many of which are important to management agencies due to commercial or conservation concerns. Maps that predict where these DSCS may occur are needed for the management and protection of these DSCS taxa and the fauna that rely on them for habitat. In this thesis, I develop …