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Articles 1 - 30 of 130
Full-Text Articles in Botany
Exploring The Relationship Between Tree Dbh And Lichen Cover On Coast Redwood, Grace M. Personeus, Sierra Gittleman, Alisa A. Zarattini
Exploring The Relationship Between Tree Dbh And Lichen Cover On Coast Redwood, Grace M. Personeus, Sierra Gittleman, Alisa A. Zarattini
IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt
We investigated the relationship between Diameter at Breast Height (DBH) and lichen cover on coast redwood (Sequoia sempervirens) to see if larger trees had higher percentages of cover. We measured cover using 10 cover classes on the southeastern and southwestern sides of trees in a secondary growth forest. We found a significant relationship between DBH and cover, yet no significant difference between the two sides measured. We suggest that further research with a larger sample size and more varied age classes will provide further insight into the relationship.
Species Boundaries Of The Rare Menzies’ Wallflower (Brassicaceae: Erysimum Menziesii), An Endemic Of The Northern California Coast, Cameron M. Jones
Species Boundaries Of The Rare Menzies’ Wallflower (Brassicaceae: Erysimum Menziesii), An Endemic Of The Northern California Coast, Cameron M. Jones
Cal Poly Humboldt theses and projects
Morphological similarity among geographically isolated populations can obscure deep evolutionary divergence, especially when convergent evolution under similar environmental conditions yields comparable phenotypes across independent lineages. Such cryptic diversity is likely underestimated in hotspots like the California Floristic Province (CFP), a global biodiversity hotspot, defined by its Mediterranean-like climate and encompassing most of California, southwestern Oregon, and northwest Baja California. The CFP is home to a disproportionate number of narrow endemics whose origins and evolutionary relationships remain poorly understood. Here, I investigate the evolutionary origins of Erysimum menziesii (Brassicaceae), a federally endangered California coastal dune endemic whose fragmented distribution has led …
Succession And Alpine Plant Habitat Of A Recently Deglaciated Foreland In The Trinity Alps, California, Sebastian Evans
Succession And Alpine Plant Habitat Of A Recently Deglaciated Foreland In The Trinity Alps, California, Sebastian Evans
Cal Poly Humboldt theses and projects
The recent extinction of the Salmon Glacier in the Trinity Alps, California, provides a rare opportunity to examine post-glacial succession in a region of high endemism experiencing climatic stress. Using a chronosequence spanning ~150 years since deglaciation, I investigated (1) vegetation successional trajectories in the foreland, (2) whether the foreland functions as a climate refugium for alpine specialists, and (3) whether facilitative interactions between the dominant vascular plant (DVP) and bryophytes occur and persist through succession. I surveyed 100 plots across 11 transects within the foreland and 40 randomized plots in adjacent ecosystems. Successional patterns and refugial potential were analyzed …
Depth And Soil Physical Context Govern Soil Organic Carbon, While Woody Cover Moderates Native Vegetation Relationships In California Rangelands, Dabid Zuniga Garcia
Depth And Soil Physical Context Govern Soil Organic Carbon, While Woody Cover Moderates Native Vegetation Relationships In California Rangelands, Dabid Zuniga Garcia
Cal Poly Humboldt theses and projects
Soil organic carbon (SOC) is central to soil function and an important component of climate mitigation in rangeland ecosystems, but the controls on SOC across California’s working rangelands remain understudied. Using data from Point Blue Conservation Science’s Rangeland Monitoring Network, this study evaluated how soil properties, vegetation structure, and recent climate relate to SOC concentration at depths of 0–10 cm and 10–40 cm across 145 ranches spanning four California regions. Linear mixed-effects models showed that SOC was consistently higher in topsoil than subsoil and highest in coastal sites relative to interior valleys. Bulk density was the strongest negative predictor of …
Assessing A Half-Century Of Change In Understory Plant Range And Frequency In The Klamath Mountains Of California, Emily Jean Jackson
Assessing A Half-Century Of Change In Understory Plant Range And Frequency In The Klamath Mountains Of California, Emily Jean Jackson
Cal Poly Humboldt theses and projects
The effects of climate change have and will continue to impact plant communities, including by potentially shifting species’ ranges towards topographically sheltered, cooler locations or higher elevations. In 2024, I resampled 140 vegetation plots established in 1969 in the Klamath Mountains of Northern California to assess range shifts of 46 understory species over a 55-year period. During this time, the elevational distribution of all species has increased significantly by an average of 26.9 m, but this increase was slower than necessary to track historic temperature niches given regional warming (215-311 m). Despite this overall increase, only four species exhibited significant …
Solvent Extracts Of Pulvigera Papillosa (Orthotrichaceae) Show No Antimicrobial Properties In Disk Diffusion Tests, Ryan A. Solorzano, Justin Paulin, Grayson Prater, Michael Lanier
Solvent Extracts Of Pulvigera Papillosa (Orthotrichaceae) Show No Antimicrobial Properties In Disk Diffusion Tests, Ryan A. Solorzano, Justin Paulin, Grayson Prater, Michael Lanier
Humboldt Journal of Microbiology
Abstract As antibiotic-resistant bacteria become more prevalent, the search for novel forms of antibiotics in the natural world has become an increasingly worthwhile endeavor. Many mosses have been found to contain antimicrobial properties, including those in the family Orthotrichaceae. Pulvigera papillosa, an Orthotrichaceous moss native to California, has thus far not been investigated to determine whether it contains antimicrobial properties. Extraction techniques using polar and nonpolar solvents have proven to be effective in extracting the secondary metabolites that allow mosses to defend themselves against a hostile microbial world. This study takes a preliminary look into the antimicrobial properties of P. …
Comparative Analysis Of Taproot And Fibrous Root System Microbiomes Under Flooding Stress, Natalie S. Kozlowski, Leighanna Jake
Comparative Analysis Of Taproot And Fibrous Root System Microbiomes Under Flooding Stress, Natalie S. Kozlowski, Leighanna Jake
Humboldt Journal of Microbiology
There has been increased interest in understanding how the microbiomes of vascular plants respond to flooding stress and, many studies have focused on monocotyledonous plants with fibrous root systems. This leaves a gap in knowledge of dicotyledonous plants with taproot systems, as previous studies have been in the context of flooding to cropland affecting major food crops which are often monocotyledonous plants with fibrous root systems. Since the structural and functional differences between these root systems may influence microbial community stability and response to flooding conditions, a study looking at both is long overdue As such, this study aims to …
Assessing Understory Along The Elk River (Hikshari') In Headwaters Forest Reserve, Humboldt County, California, Julie R. Meyers, Aliyah M. Ingram, Caleb N. Larkin, Joshua L. Carpenter
Assessing Understory Along The Elk River (Hikshari') In Headwaters Forest Reserve, Humboldt County, California, Julie R. Meyers, Aliyah M. Ingram, Caleb N. Larkin, Joshua L. Carpenter
Environmental Science & Management Senior Capstones
Northern California’s extensive logging history and lack of forest management has altered old-growth coast redwood (Sequoia sempervirens) forests, leaving dense, homogenous second and third-growth forest stands. This has led to the use of modern restoration techniques such as variable density thinning (VDT) which aims to rehabilitate old-growth forest conditions by improving stand heterogeneity and light availability for understory species. Our study was done in Headwaters Forest Reserve (HFR) along the Elk River (Hikshari’) Trail in Humboldt County, California. Initially, the project was supervised by the Bureau of Land Management (BLM) Arcata Field Office. However, the 2025 U.S. government …
Place-Based Learning Practices: A Diptych Case Study Of Human And More-Than-Human Relationality At The Tribal And Western Academic Institutional Interface, Karley M. Rojas-Vienneau
Place-Based Learning Practices: A Diptych Case Study Of Human And More-Than-Human Relationality At The Tribal And Western Academic Institutional Interface, Karley M. Rojas-Vienneau
Cal Poly Humboldt theses and projects
The ‘Place-Based Learning Practices Project’ is a graduate project under the Native American Studies Department Rou Dalagurr Food Sovereignty Lab and Traditional Ecological Knowledges Institute (FSL). Making contributions at the intersection of Western academia and Indigenous science, it imagines and realizes content, policies, and protocols surrounding two case studies and the larger cal poly humboldt (cph) institution which respect, honor, and uplift Indigenous sovereignty and resurgence in partnership with the Blue Lake Rancheria Tribe and the greater regional tribal community. Encompassing two projects internal and external to the institution, I aim to address the construction of controlled and protective environments …
Impact Of An Herbicide Treatment In An Annual Grass Invaded Sagebrush Steppe, Jordan Dino Santia
Impact Of An Herbicide Treatment In An Annual Grass Invaded Sagebrush Steppe, Jordan Dino Santia
Undergraduate Scholarship
Globally, rangelands are being threatened by invasive annual grasses (IAGs) that alter fire regimes, drive vegetation type conversion, and alter ecosystem function. This study evaluates vegetation responses to an Imazapic treatment applied in 2020 to control a population of Taeniatherum caput-medusae, an IAG, that flourished following a severe wildfire in 2013. The site, located on a Bureau of Land Management (BLM) grazing allotment east of Klamath Falls, Oregon, has been monitored annually using the Assessment, Inventory, and Monitoring (AIM) protocol since the Summer of 2022. Over this period, very little T. caput-medusae has been detected while bare ground has …
Building Detailed And Accurate Whole-Plant Concepts: A Morphometrics-Informed Reconstruction Of A Zosterophyll From The Lower Devonian Of Wyoming, Samar R. El-Abdallah
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 …
Evolutionary Origins Of Secondary Growth - The Periderm Perspective: Integrating Evidence From Fossils And Living Plants, Madison A.K. Lalica
Evolutionary Origins Of Secondary Growth - The Periderm Perspective: Integrating Evidence From Fossils And Living Plants, Madison A.K. Lalica
Cal Poly Humboldt theses and projects
Periderm is a structural feature with roles in protection of inner plant tissues and wound healing. Knowledge of periderm occurrences in the fossil record and living lineages outside the seed plants is limited and its evolutionary origins remain poorly explored. Here, I review the known taxonomic distribution of canonical periderm (typical ontogenetic stage) and wound periderm (self-repair mechanism). To this sparse body of data I add new observations and experiments on living plant lineages and new occurrences from the fossil record. One of the latter, documented in the new early euphyllophyte species Nebuloxyla mikmaqiana, joins the oldest known periderm …
Assessing Relocation Habitats And Assisted Migration Of The Lassics Lupine, An Endangered California Serpentine-Endemic, Caitlyn M. Allchin
Assessing Relocation Habitats And Assisted Migration Of The Lassics Lupine, An Endangered California Serpentine-Endemic, Caitlyn M. Allchin
Cal Poly Humboldt theses and projects
The Lassics lupine, Lupinus constancei, is a serpentine species endemic to the Lassics Mountains of northern California, listed as critically imperiled and federally endangered. Increased encroachment from reduced fire intervals has led to elevated herbivory from small mammals. While deployment of exclosure cages has decreased negative impacts, diminishing snowpack from shifting climate continues to threaten the Lassics lupine. To locate possible refugia, I evaluated alternative sites for assisted migration. I built a habitat suitability model (HSM) using MaxEnt software and WorldClim variables to predict optimal habitat. I then evaluated aerial imagery, topography, and geology to identify areas for microhabitat …
Characterizing New Plant Fossils With Woody Growth From The Battery Point Formation Of Quebec (Canada), Emma T. Casselman
Characterizing New Plant Fossils With Woody Growth From The Battery Point Formation Of Quebec (Canada), Emma T. Casselman
Cal Poly Humboldt theses and projects
The oldest woody growth has been recognized in several Early Devonian (ca. 410-395 Ma) euphyllophytes. Their taxonomic diversity is difficult to evaluate due to a lack of quantitative methods for comparing plants based on secondary xylem anatomy. In turn, this hinders understanding of their implications for the evolution of plant development. To develop metrics that quantify secondary xylem anatomy and allow for conclusive comparisons, I investigated extant taxa and Early Devonian fossil woody taxa. I developed multiple metrics for quantifying tracheid size as a function of position in the secondary xylem and tested them on a dataset of extant gymnosperms. …
Prevalence Of Hesperevax Sparsiflora Var. Brevifolia (Short-Leaved Evax) At Ocean Ranch, Humboldt County, California: Exploring The Effects Of Disturbance, Shelby Diquirco, Matthew Estrada, Alana T. Fraley, Alexander D. Smith
Prevalence Of Hesperevax Sparsiflora Var. Brevifolia (Short-Leaved Evax) At Ocean Ranch, Humboldt County, California: Exploring The Effects Of Disturbance, Shelby Diquirco, Matthew Estrada, Alana T. Fraley, Alexander D. Smith
Environmental Science & Management Senior Capstones
The prevalence of special-status plants within a landscape can be an indicator of the ecological health of that site, and therefore inform restoration efforts and post-restoration monitoring. Hesperevax sparsiflora var. brevifolia (short-leaved evax) is a special status species found within the Ocean Ranch unit of Humboldt, California. A primary threat to native plant communities are invasive plant species. Coastal dune ecosystems are largely dominated by invasive species, including Ammophila arenaria (European beachgrass). To work towards the eradication of A. arenaria, the California Department of Fish and Wildlife utilized treatment combinations of herbicide and prescribed fire at Ocean Ranch in …
Changes And Relationships Of Soil Aluminum, Organic Matter, And Hydrogen Ion Concentration With Rye Cover Crop, Arron Wilder
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 …
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 …
Assessing The Recovery Of Forest Understory Vegetation After Clearcut Logging Across A 445-Year Chronosequence, Molly Smith Metok
Assessing The Recovery Of Forest Understory Vegetation After Clearcut Logging Across A 445-Year Chronosequence, Molly Smith Metok
Cal Poly Humboldt theses and projects
The conversion of natural forested lands to managed forests has reduced the amount of older, structurally diverse forests worldwide. In conifer forests of the Pacific Northwest (USA) – where the understory plant communities comprise only 1% of forest biomass but represent 90% of the plant species richness – the long-term impacts of timber harvesting are not fully understood. I used a chronosequence of forests in southwestern Oregon that ranged from 25 to 445 years of age to compare changes in plant communities in logged (i.e., managed) stands with that of stands in late succession and old growth conditions. The chronosequence …
Macrolichen Inventory Of The Horse Mountain Botanical Area, Six Rivers National Forest, California, Usa, Sarah Norvell Conway
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, …
Mechanically Injurious Plants, James P. Smith Jr
Mechanically Injurious Plants, James P. Smith Jr
Botanical Studies
No abstract provided.
An Annotated List Of The Poisonous And Injurious Vascular Plants Of The United States, James P. Smith Jr
An Annotated List Of The Poisonous And Injurious Vascular Plants Of The United States, James P. Smith Jr
Botanical Studies
No abstract provided.
Two Hemlocks, James P. Smith Jr
Purposeful Use Of Poisonous Plants, James P. Smith Jr
Purposeful Use Of Poisonous Plants, James P. Smith Jr
Botanical Studies
No abstract provided.
Poisonous Plants: A Glossary Of Commonly Used Terms, James P. Smith Jr
Poisonous Plants: A Glossary Of Commonly Used Terms, James P. Smith Jr
Botanical Studies
No abstract provided.
Poisonous Plants Of Home And Garden, James P. Smith Jr
Poisonous Plants Of Home And Garden, James P. Smith Jr
Botanical Studies
No abstract provided.
Nikolai Ivanovich Vavilov, James P. Smith Jr
Food Plants With Toxic Properties, James P. Smith Jr
Food Plants With Toxic Properties, James P. Smith Jr
Botanical Studies
No abstract provided.
Richard Evans Schultes, James P. Smith Jr
Forecasting The Outcomes Of Managing A Rare Endemic Plant At Its Elevational Limit Under Climate Change Scenarios, Ethan Reibsome
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 …
Effects Of Redwood Bark And Leaf Leachate On Different Lichen Populations Found Within The Redwood Forest Of Arcata, Ca, Courtney Michelle Harris, Phoebe Hughes
Effects Of Redwood Bark And Leaf Leachate On Different Lichen Populations Found Within The Redwood Forest Of Arcata, Ca, Courtney Michelle Harris, Phoebe Hughes
IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt
No abstract provided.