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Articles 1 - 15 of 15
Full-Text Articles in Life Sciences
Genetic Evaluation Of The Current Distribution And Possible Diffrentations Between Lasiurus Borealis And Lasiurus Frantzii In Southwestern North America, Zeinab M. Haidar
Genetic Evaluation Of The Current Distribution And Possible Diffrentations Between Lasiurus Borealis And Lasiurus Frantzii In Southwestern North America, Zeinab M. Haidar
Cal Poly Humboldt theses and projects
Several recent accounts of overlap and historic misidentifications regarding two species of the genus Lasiurus, Western red bat (Lasiurus frantzii) and Eastern red bat (Lasiurus borealis), have cast doubt on our understanding of their distribution, assumed spatial allopatry, and interactions in the United States Southwest. With the use of morphometrics and genetic sequencing, utilizing tissue collected from specimens throughout California and adjoining states, we have reassessed the current distribution, best practices for field identification, and genetic differentiation between both species. Appropriate species classification by region was achieved utilizing mitochondrial DNA, targeting the cytochrome c oxidase …
Western Gulls’ (Larus Occidentalis) Reproductive And Behavioral Responses To Human Disturbance, Lilamarie 'Asta Bowen
Western Gulls’ (Larus Occidentalis) Reproductive And Behavioral Responses To Human Disturbance, Lilamarie 'Asta Bowen
Cal Poly Humboldt theses and projects
Human disturbances can negatively affect wildlife by causing stress, altering behavior, or even impacting populations through changes in survival or productivity. Colonial-nesting seabirds are of particular concern due to population declines and their gregarious and conspicuous nature, which may attract human visitors. However, the effects of nearby human activities, though frequently negative, could be neutral or even positive through phenomena like habituation to human activities or subsidization by human-supplied food sources. In this observational study, I evaluated relative support for three hypotheses which may explain how Western Gulls are impacted by human activity: disturbance, habituation, and subsidization. I investigated this …
Insights Into The Conservation Of The Rare Perennial Herb, Astragalus Applegatei, Sean Stewart
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 …
Effects Of Ph, Eelgrass, And Settlement Substrate On The Growth Of Juvenile Magallana (Crassostrea) Gigas, A Commercially Important Oyster Species, Johnny S. Roche
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 …
Host-Microbe Interactions In Non-Native Estuarine Anemones: Biogeography And Temperature, Parker K. Lund
Host-Microbe Interactions In Non-Native Estuarine Anemones: Biogeography And Temperature, Parker K. Lund
Cal Poly Humboldt theses and projects
Non-native species are increasing in prevalence around the world, resulting in negative economic and ecological impacts. However, the broad distributions of non-native species also offer a system for investigating the response of host-associated microbial communities to environmental factors across a range of ecological scales. At the broadest scale, I investigated the geography of microbial communities in the non-native estuarine anemone Diadumene lineata on the west coast of the United States of America. Across latitudes, microbial community composition was very similar and displayed a high percentage of Klebsiella spp. at all sites. However, the communities in California tended to exhibit higher …
Using Multiscale Ensemble Habitat Models To Identify Wildfire Risk To Habitat For An Iconic Forest Species, Logan Baker Hysen
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 …
Comparing Mexican Spotted Owl Habitat Suitability In Two Different Habitat Types Using A Multi-Scale Ensemble Learning Framework, Danial Nayeri
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 …
Polymorphism Of Melanin-Based Pigments In Barn Owls In Winegrape Vineyards In Napa Valley, California, Laura Mariana Echávez Montenegro
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 …
Sympatric Carnivores And Vegetation Structure Influence The Distribution And Abundance Of Humboldt Martens In Northern California, Erika L. Anderson
Sympatric Carnivores And Vegetation Structure Influence The Distribution And Abundance Of Humboldt Martens In Northern California, Erika L. Anderson
Cal Poly Humboldt theses and projects
The Humboldt marten (Martes caurina humboldtensis) is a species facing conservation concern in Oregon and California. Historical populations were subjected to unregulated fur trapping and timber harvest throughout the late 19th and early 20th centuries leading to a 90% decline in their distribution. As such, the Humboldt marten is listed as a state endangered species in California, and the analogous ‘coastal marten’ is listed as federally threatened under the Endangered Species Act and classified as a Species of Greatest Conservation Need in Oregon and California. Contemporary populations are small, and isolated, and threatened by habitat loss …
Identifying Habitat Suitability And Connectivity For Roosevelt Elk (Cervus Canadensis Roosevelti) On The North Coast Of California, Ashley Ann Harper
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 …
Effects Of Oyster Aquaculture On Elasmobranch Abundance And Habitat Use In Humboldt Bay, Ca, Rose Harman
Effects Of Oyster Aquaculture On Elasmobranch Abundance And Habitat Use In Humboldt Bay, Ca, Rose Harman
Cal Poly Humboldt theses and projects
Habitat modification from aquaculture can have large effects on natural communities, with the habitat complexity provided by aquaculture structure positively influencing benthic invertebrates and small fish abundance. However, the effects of aquaculture on larger predatory fish like elasmobranchs (i.e., sharks and rays), which use nearshore habitat to forage and provide top-down control of these ecosystems, is largely unknown. Over two years, I deployed baited remote underwater video systems (BRUVS) to examine the effects of oyster aquaculture and environmental variables such as habitat (mudflat or eelgrass), salinity (ppt), turbidity (m), temperature (°C), pH (mV), dissolved oxygen (mg · L-1), …
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 …
Carnivore And Ungulate Occurrence In A Fire-Prone Region, Sara J. Moriarty-Graves
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 …
Will Climate Warming Amplify The Competitive And Predatory Effects Of A Range-Expanding Marine Gastropod (Acanthinucella Spirata)?, Bailey N. Mccann
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 …
A Cladoxylopsid With Complex Vascular Architecture From The Early Devonian Battery Point Formation (Québec, Canada), Jessica Chu
A Cladoxylopsid With Complex Vascular Architecture From The Early Devonian Battery Point Formation (Québec, Canada), Jessica Chu
Cal Poly Humboldt theses and projects
Cladoxylopsids are seed-free plants that formed the world’s earliest forests and gave rise to horsetails (sphenopsids), but their evolutionary origins are poorly understood. Here, I describe a new Early Devonian cladoxylopsid from the Emsian (400-395 Ma) Battery Point Formation (Québec, Canada). The structural features of this plant indicate taxonomic affinity to cladoxylalean cladoxylopsids and its phylogenetic position supports placement in genus Cladoxylon (the proposed name, Cladoxylon kespekianum sp. nov., to be formalized by peer-reviewed publication). Specimens of this plant are permineralized in calcium carbonate and were studied using the acetate peel technique with light and electron microscopy. Cladoxylon kespekianum is …