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Cal Poly Humboldt

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Articles 61 - 90 of 175

Full-Text Articles in Ecology and Evolutionary Biology

Polymorphism Of Melanin-Based Pigments In Barn Owls In Winegrape Vineyards In Napa Valley, California, Laura Mariana Echávez Montenegro Jan 2023

Polymorphism Of Melanin-Based Pigments In Barn Owls In Winegrape Vineyards In Napa Valley, California, Laura Mariana Echávez Montenegro

Cal Poly Humboldt theses and projects

Many raptor species exhibit plumage polymorphism. Through the expression of a particular phenotype, polymorphism allows individuals to exploit alternative spatial or temporal environments and food resources most successfully. Barn Owls display within-species variation in their plumage, ranging from reddish to whitish and from heavily spotted to having no spots at all. In heterogeneous landscapes in Europe and the Middle East, reddish Common Barn Owls (Tyto alba) inhabit territories with proportionally more arable fields and consume proportionally more voles than mice in contrast to their whiter counterparts; a phenomenon known as habitat matching choice. This study sought to quantify …

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Identifying Habitat Suitability And Connectivity For Roosevelt Elk (Cervus Canadensis Roosevelti) On The North Coast Of California, Ashley Ann Harper Jan 2023

Identifying Habitat Suitability And Connectivity For Roosevelt Elk (Cervus Canadensis Roosevelti) On The North Coast Of California, Ashley Ann Harper

Cal Poly Humboldt theses and projects

As human development continues to expand, wildlife managers are faced with problems arising from human-wildlife conflict. To address conflict, it is vital to identify how animals view the landscape and move across areas of differing land use. On the North Coast of California, Roosevelt elk (Cervus canadensis roosevelti) are widely considered to be a valuable resource but are viewed by some as a nuisance due to economic losses caused by property damage. The aim of this study was to identify suitable habitat and movement corridors for Roosevelt elk across Humboldt and Del Norte counties in northern California. Suitable …

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Will Climate Warming Amplify The Competitive And Predatory Effects Of A Range-Expanding Marine Gastropod (Acanthinucella Spirata)?, Bailey N. Mccann Jan 2023

Will Climate Warming Amplify The Competitive And Predatory Effects Of A Range-Expanding Marine Gastropod (Acanthinucella Spirata)?, Bailey N. Mccann

Cal Poly Humboldt theses and projects

The effects of climate warming on the distribution of range-expanding species are well documented, but the interactive effects of climate warming and range-expanding species on recipient communities remain understudied. For example, with climate warming, range-expanding species may become a threat to local biodiversity due to their relatively stronger competitive or predatory effects on potentially weakened, or less well-adapted recipient communities. Acanthinucella spirata is a predatory marine gastropod that has expanded its distribution north along the California coast since the Pleistocene via a poleward geographical range shift, tracking climatic warming. To assess whether A. spirata has stronger predatory effects on the …

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Effects Of Ph, Eelgrass, And Settlement Substrate On The Growth Of Juvenile Magallana (Crassostrea) Gigas, A Commercially Important Oyster Species, Johnny S. Roche Jan 2023

Effects Of Ph, Eelgrass, And Settlement Substrate On The Growth Of Juvenile Magallana (Crassostrea) Gigas, A Commercially Important Oyster Species, Johnny S. Roche

Cal Poly Humboldt theses and projects

Worsening ocean acidification (OA), resulting from ongoing absorption of atmospheric carbon dioxide (CO2) by the oceans, threatens marine life globally. Calcifying organisms, especially their early life stages, are particularly vulnerable; this includes the economically important Pacific oyster, Magallana (Crassostrea) gigas. Uptake of dissolved CO2 through photosynthesis by seagrasses, like eelgrass (Zostera marina), may benefit calcifying organisms by increasing pH and carbonate availability. I conducted laboratory and field experiments to quantify carbonate chemistry modification by eelgrass and potential mitigation of OA impacts on growth in juvenile Pacific oysters. In the laboratory experiment, daytime …

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Carnivore And Ungulate Occurrence In A Fire-Prone Region, Sara J. Moriarty-Graves Jan 2023

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 …

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Effects Of Depth, Distance To Shore, And Water Velocity On Organismal And Extra-Organismal Environmental Dna Concentrations In A Large River, Dylan Keel Jan 2023

Effects Of Depth, Distance To Shore, And Water Velocity On Organismal And Extra-Organismal Environmental Dna Concentrations In A Large River, Dylan Keel

Cal Poly Humboldt theses and projects

Environmental DNA (eDNA) is a sensitive tool for detection of aquatic species and concentrations of eDNA in water samples have been useful for estimating abundance. This study evaluated the effects of depth, distance to shore, and water velocity on the concentration of organismal and extra-organismal eDNA concentrations in the Klamath River, California (basin area ≅ 40,000 km2). At each of six river cross sections 32 water samples were collected, including surface samples and depth samples evenly distributed across the cross section, and eDNA concentrations were determined for the parasite Ceratonova shasta and Chinook salmon, Oncorhynchus tshawytscha, using …

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Comparing Mexican Spotted Owl Habitat Suitability In Two Different Habitat Types Using A Multi-Scale Ensemble Learning Framework, Danial Nayeri Jan 2023

Comparing Mexican Spotted Owl Habitat Suitability In Two Different Habitat Types Using A Multi-Scale Ensemble Learning Framework, Danial Nayeri

Cal Poly Humboldt theses and projects

Habitat fragmentation and loss are major threats to species conservation worldwide. Studying species-habitat relationships is a crucial first step toward understanding species habitat requirements, which is necessary for conservation and management planning. However, some species inhabit a range of habitat types, potentially making the use of range-wide habitat models inappropriate due to non-stationarity. The Mexican spotted owl (Strix occidentalis lucida) (MSO) is a species that inhabits both forests and rocky canyonlands, two habitats with large differences in environmental conditions. It is unclear whether the species uses habitat differently in these two habitat types or if previously builthabitat models …

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Insights Into The Conservation Of The Rare Perennial Herb, Astragalus Applegatei, Sean Stewart Jan 2023

Insights Into The Conservation Of The Rare Perennial Herb, Astragalus Applegatei, Sean Stewart

Cal Poly Humboldt theses and projects

As anthropogenic activities expand, conservation of rare and endangered species is critical to reduce extinction risks. Collecting and analyzing demographic data can assist in the development of conservation strategies and can help evaluate the success of existing strategies. In this study, I built integral projection models from five years of demographic data and conducted a population viability analysis on four populations of the rare perennial herb, Astragalus applegatei, to inform conservation decisions. I also assessed how planting A. applegatei seedlings might contribute to the growth of an extant population. I found that one population was already below the extinction …

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Using Multiscale Ensemble Habitat Models To Identify Wildfire Risk To Habitat For An Iconic Forest Species, Logan Baker Hysen Jan 2023

Using Multiscale Ensemble Habitat Models To Identify Wildfire Risk To Habitat For An Iconic Forest Species, Logan Baker Hysen

Cal Poly Humboldt theses and projects

Large and severe wildfires, exacerbated by climate change and human behavior, are occurring more frequently in many forests across the western United States. While wildfire is a natural part of most terrestrial ecosystems, rapidly changing fire regimes have the potential to alter habitat beyond the adaptive capabilities of species. Spatial assessments of wildfire risks to species habitat may allow managers to pinpoint locations for management activities. To illustrate this, I spatially assessed wildfire risk within habitat that supports the nesting activity of the federally threatened northern spotted owl (Strix occidentalis caurina) in the California redwood coast ecoregion. To …

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Variation In Coastal Macroinvertebrate Species Diversity On Intertidal Boulders In Trinidad, California., Louis Antonelli, Alexandra Winkler, Theron Taylor, Natalie Greenleaf Oct 2022

Variation In Coastal Macroinvertebrate Species Diversity On Intertidal Boulders In Trinidad, California., Louis Antonelli, Alexandra Winkler, Theron Taylor, Natalie Greenleaf

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

Coastal environments of Humboldt County provide an optimal habitat for a diversity of macroinvertebrates. This study’s focus is to determine the differences in diversity of coastal macroinvertebrate (CM) species on intertidal boulders. Eleven CM species were visually counted within a one-square-meter quadrat along two height strata of five intertidal boulders. Based upon the Shannon-Wiener diversity index, diversity was measured between the CM species in the lower region (0-1 meter from base of boulder) and the upper region (1-2 meters from base of boulder). The resulting data showed the lower regions of the boulders had a higher average diversity rating, as …

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Proximate And Ultimate Perspectives On Romantic Love Sep 2022

Proximate And Ultimate Perspectives On Romantic Love

The International Journal of Ecopsychology (IJE)

Romantic love is a phenomenon of immense interest to the general public as well as to scholars in several disciplines. It is known to be present in almost all human societies and has been studied from a number of perspectives. In this integrative review, we bring together what is known about romantic love using Tinbergen’s “four questions” framework originating from evolutionary biology. Under the first question, related to mechanisms, we show that it is caused by social, psychological mate choice, genetic, neural, and endocrine mechanisms. The mechanisms regulating psychopathology, cognitive biases, and animal models provide further insights into the mechanisms …

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Activity Patterns Of The Del Norte Salamander (Plethodon Elongatus): Monitoring Plethodontid Behavior Using Pit Tag Surveys, Sabrina Horrack Jan 2022

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, …

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Evaluating Relative Abundance, Fish Length, And Marine Protected Area Effectiveness For Four Key Rocky Reef Species Along The Northern Californian Coast, Leon Davis Jan 2022

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 …

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Northern Elephant Seal (Mirounga Angustirostris) Colony Establishment And Growth In The King Range National Conservation Area, California, Emma Hatton Levy Jan 2022

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 …

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Demographic Modeling Of Conservation Strategies For The Yosemite Toad (Anaxyrus Canorus), Corrina Rebecca Kamoroff Jan 2022

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 …

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Forecasting The Outcomes Of Managing A Rare Endemic Plant At Its Elevational Limit Under Climate Change Scenarios, Ethan Reibsome Jan 2022

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 …

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Evaluating The Use Of Barn Owl Nest Boxes For Rodent Pest Control In Winegrape Vineyards In Napa Valley, Ashley N. Hansen Jan 2022

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 …

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Phylogenetic And Geographic Relationships Of Cheilostome Bryozoans In The Eastern Pacific, Hannah E. Lee Jan 2022

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.

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Investigating The Genetic Diversity Of Immune Genes In Non-Native Populations Of American Bullfrogs (Rana Catesbeiana), Luisa Nereyda Segovia Jan 2022

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, …

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Degradation And Nitrogen Cycling In The Context Of Biodiversity-Ecosystem Function Relationships In The Inquiline Bacterial Community Of Darlingtonia Californica, Megan Teigen Jan 2022

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 …

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Data Repository For "Use Of Redwood Basal Hollows By Bats: A Focus On The Townsend’S Big-Eared Bat On The North Coast Of California", Amon J. Armstrong Jan 2021

Data Repository For "Use Of Redwood Basal Hollows By Bats: A Focus On The Townsend’S Big-Eared Bat On The North Coast Of California", Amon J. Armstrong

Research Data Sets

Loss of roosting resources, either through disturbance or removal, negatively affects bats. Identifying sensitive species and determining roost requirements are critical components in conserving their habitat. Cavity roosting bats on the North Coast of California are known to use hollows in large redwood trees. In this study, we 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 was used as an index of roosting activity. Nine …

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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 Jan 2021

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 …

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Recreation, Vegetation Management, And Disease Impact Sympatric Carnivore Activity In California's East Bay Parks, Leigh J. Douglas Jan 2021

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 …

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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 Jan 2021

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 …

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Noninvasive Genetic Sampling With A Bayesian Spatial Capture-Recapture Analysis To Estimate Abundance Of Roosevelt Elk (Cervus Canadensis Roosevelti), Makenzie Henk Jan 2021

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 …

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The Homology Of Sarcopterygian Gills, Kyle Orr Jan 2021

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 …

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Comparison Of Standard And Environmental Dna Methods For Estimating Chinook Salmon Smolt Abundance In The Klamath River, California, Doyle Joseph Coyne Jan 2021

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 …

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Seed Bank Composition Within Two Sagebrush Communities: A Comparison Of Drought, Microsite, And Aboveground Community Effects, Allison Marie Nunes Jan 2021

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 …

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Do Beaver Dam Analogues Act As Passage Barriers To Juvenile Coho Salmon And Juvenile Steelhead Trout?, Christopher G. O'Keefe Jan 2021

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 …

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Social Comparison Tendencies And The Reward Value Of Same-Sex Beauty Among Heterosexual Women, Melissa M. Martin Ms. Jan 2021

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 …

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