Life Sciences Commons^™

Regional Impacts Of Invasive Species And Climate Change On Black Ash Wetlands, Joseph Shannon

Dissertations, Master's Theses and Master's Reports

For more than a decade intensive research on the ecohydrology of black ash wetland ecosystems has been performed to understand these systems before they are drastically altered by the invasive species, emerald ash borer (EAB). In that time there has been little research aimed at the scale and persistence of the alterations. Three distinct but related research articles will be presented to demonstrate a method for moderate resolution mapping of black ash across its entire range, understand the relative impacts of EAB and climate change on probable future wetland conditions, and develop an experimental and modeling approach to quantify and …

Wildlife Forage Recovery Following Boreal Wildfire, Alexis Jorgensen, Jennifer Baltzer

Theses and Dissertations (Comprehensive)

Climate change is altering the boreal wildfire regime through increases in the extent and severity of burning and reductions in fire return intervals. These changes can alter the regeneration trajectory of canopy species and ground vegetation, with implications for wildlife habitat. There is some uncertainty about the timelines of when different animal species will use burned areas as their preferred forage taxa recover following fire, and how such recovery is mediated by environmental factors. Here, we aim to address these knowledge gaps through the following questions: 1) What are the main forage types consumed by boreal wildlife and how much …

Dietary Protein Content And Digestibility Influences Discrimination Of Amino Acid Nitrogen Isotope Values In A Terrestrial Omnivorous Mammal, John P. Whiteman, Mauriel Rodriguez Curras, Kelli L. Feeser, Seth D. Newsome

Biological Sciences Faculty Publications

RATIONALE: Ecologists increasingly determine the δ¹⁵N values of amino acids (AA) in animal tissue; "source" AA typically exhibit minor variation between diet and consumer, while "trophic" AA have increased δ¹⁵N values in consumers. Thus, trophic-source δ¹⁵N offsets (i.e., Δ¹⁵N_T-S) reflect trophic position in a food web. However, even minor variation in δ¹⁵N_{source AA} values may influence the magnitude of offset that represents a trophic step, known as the trophic discrimination factor (i.e., TDF_T-S). Diet digestibility and protein content can influence the δ¹⁵N values …

Insect Community Associated With Black Cherry (Prunus Serotina) In The Allegheny National Forest, Craig James Larcenaire

Graduate Theses, Dissertations, and Problem Reports

Black cherry (Prunus serotina Ehrh.) is valuable species managed for its economic and ecologic benefits. This species grows best in the environment of the Allegheny Plateau region in northwestern Pennsylvania. Land managers on the Allegheny National Forest (ANF) have been managing black cherry for a variety of goals and purposes. Over the last few decades, the land managers have noticed a decline in the natural regeneration of black cherry in the forest. Because the black cherry flowers are self-incompatible and require animal pollinators to transfer the pollen from one tree to another one hypothesis for this decline could be …

Southern Pine Beetle-Specific Rna Interference Demonstrates No Effects On Nontarget Insects, Hannah Marie Hollowell

Theses and Dissertations--Entomology

The endemic southern pine beetle (SPB), Dendroctonus frontalis Zimmermann, is a highly destructive bark beetle that has devastated coniferous forests of the southern United States for decades. Traditional management strategies have been unable to respond effectively to largescale SPB outbreaks, prompting exploration of novel techniques including RNA interference (RNAi). Double-stranded RNAs (dsRNAs) are effective at triggering gene silencing and inducing mortality in SPB, but determining delivery methods and demonstrating specificity of the treatments is necessary before this technology may progress to deployment.

I evaluated three SPB-specific dsRNAs on model nontarget insects to assess potential lethal effects, sublethal effects such as …

Three Essays On “Energy , Environment, And Developmental Economics”, Bolarinwa Ajanaku

Graduate Theses, Dissertations, and Problem Reports

This dissertation examines topics related to renewable energy development and investment planning, energy markets, environment degradation and economic development. The substantial ecological costs of deforestation are well known and considered globally important due to biodiversity loss, land degradation, soil erosion, and contributions to climate change. The first essay focuses upon understanding the tradeoff between development and deforestation in Africa. In the second essay, spatial analysis and Geographic Information System (GIS) are applied to determine potential locations for wind farms development in the state of West Virginia. Lastly, the third essay examines the role of wind power penetration on wholesale electricity …

The Role Of Tree Species, The Herb Layer, And Watershed Characteristics On Nitrogen Cycling In A Central Appalachian Hardwood Forest, Sian E. Eisenhut

Graduate Theses, Dissertations, and Problem Reports

Little is known about the forest herbaceous layer’s contributions to nitrogen (N) cycling under varying levels of N deposition, at different stages of forest succession, in watersheds with different aspects, and under different tree species. The objectives of this study were to quantify nitrogen reductase activity (NRA) of two tree species, red maple and sugar maple, and surrounding common herb-layer species at the tissue (foliage, roots) and plot level and to assess how these species affect the concentrations of nitrate, ammonium, and organic N in soil water collected in lysimeters beneath these trees. Different watersheds located at the Fernow Experimental …

Sula Study Revisited: 20-Year Post-Fire Regeneration In The Southern Bitterroot Valley, Montana., Luke Alan Rymniak

Graduate Student Theses, Dissertations, & Professional Papers

In the summer of 2000, a number of large fires burned in the southern Bitterroot Valley near Sula, Montana. Research was conducted in 2001 and 2003 in the fire-affected areas of the French Basin and Larid Creek areas in order to investigate the effects of environmental variables, fire severity, and post-fire management on vegetation regeneration. In 2020 these areas were remeasured to understand trends over time by evaluating the impact of these same factors 20 years post fire. The results showed that the effects of environmental variables, fire severity, and post-fire management on vegetation regeneration were varied. The most influential …

White River Aspen Management Project, Usda Forest Service

Aspen Bibliography

Comments Welcome

The White River National Forest (WRNF) welcomes your comments on its proposal to conduct vegetation management activities designed to sustain and expand aspen (Populus tremuloides) forests on National Forest System (NFS) lands. Your comments will help us further develop the proposed action, potential alternatives, and complete an environmental assessment. The assessment will be used to determine whether to prepare an environmental impact statement or a finding of no significant impact. Instructions for submitting comments are described on the last page. Additional project information is available here: https://www.fs.usda.gov/project/?project=59419

This Notice of Proposed Action (NOPA) is also requesting …

Effects Of Prescribed Fire On Drought Resistance And Recovery In Mixed Conifer Forests Of Lassen Volcanic National Park, California, Zachary J. Wenderott

Cal Poly Humboldt theses and projects

Forests throughout much of the western United States are experiencing increasing climatic variability, often resulting in decreased forest productivity and elevated likelihood of tree mortality. Severe drought, such California’s recent 2012-2015 drought, are projected to increase in intensity, frequency, and severity throughout much of this region in coming years. Forest management has long relied on prescribed fire and mechanical thinning to reduce fuel loads and ameliorate potential fire hazards. These treatments may also have the ability to reduce stand density, alleviate competitive pressures, and allow residual trees access to critical resources during periods of extreme stress. Utilizing a long-term National …

Conifer Encroachment And Removal In A Northern California Oak Woodland: Influences On Ecosystem Physiology And Biodiversity, Gabriel S. Goff

Cal Poly Humboldt theses and projects

Oregon white oak (Quercus garryana) woodlands across their range are becoming increasingly threatened by encroaching Douglas-fir encroachment (Pseudotsuga menziesii) as a result of fire exclusion. Using water potential (Ψ), stomatal conductance (g_s), xylem water stable isotopes (dD), and three metrics of biodiversity, this study investigates the effects of conifer encroachment and removal at the ecosystem-scale. The study was set in an Oregon white oak woodland in northern California and compared three levels of encroachment before and after conifer removal. Findings indicate that heavily encroached stands have the least amount of water stress and gas …

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 …

The Politics Of Biomass Energy In California: How External Benefits Are Used To Support An Economically Marginal Sector, Dana L. Dysthe

Cal Poly Humboldt theses and projects

Since the 1990s, there has been a decline in biomass energy generation in California. In order to promote state governmental policies aiming to increase biomass energy generation in California, the sector has been linked to a series of external benefits that biomass energy purportedly brings. Through document analysis, semi-structured interviews, and participant observation, five distinct external benefits were identified that have been used to promote the biomass energy sector. These external benefits are: renewable energy generation, air quality improvements, promotion of forest restoration and fuel removal projects, disposal of wood waste from agricultural and forestry sectors, and rural economic development. …

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 …

Influences On Conifer Drought Responses In Northern California, Wallis L. Robinson

Cal Poly Humboldt theses and projects

California is experiencing increasingly severe and prolonged droughts, which are contributing to changes in tree stress and forest mortality. Many factors affect a tree’s drought response, including competition, climate, and site and tree characteristics. Northern California provides a suitable venue to explore the effects of these factors, as it spans a variety of site conditions and includes habitat for conifers with different adaptations and requirements. This study used annual ¹³C discrimination and growth metrics to assess differences in drought resistance and resilience in conifers adapted to coastal and montane ranges at both wet and dry sites, as well as …

Evaluating Immaturity Risk In Young Stands Of The Serotinous Knobcone Pine (Pinus Attenuata), Katherine Marlin

Cal Poly Humboldt theses and projects

As wildfire becomes increasingly frequent, many plant populations risk local extirpation if fire recurs too soon, a problem dubbed “immaturity risk”. We studied the regeneration of a serotinous conifer species, knobcone pine (Pinus attenuata), as a function of the time between high-severity fires (6-79 years). We evaluated age, cone production, and regeneration at two burned sites in northern California, the Ranch Fire (2018) in Mendocino National Forest, and the Carr Fire (2018) in Whiskeytown National Recreation Area. We found an average of 30.5 filled seeds in closed, brown cones (42% viability of filled seeds). The bulk of the …

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 …

Forest Policies And Adaptation To Climate Change In Maine: Stakeholder Perceptions And Recommendations, Alyssa R. Soucy, Sandra De Urioste-Stone, Ivan J. Fernandez, Aaron Weiskittel, Parinaz Rahimzadeh-Bajgiran, Tom Doak

Maine Policy Review

Socioeconomic pressures require forest management to address the impacts of climate change. However, we must ask, Are current forest policies sufficient to deal with the impacts of climate change? Here, we report on two surveys of forest stakeholders in Maine including woodlot owners and forestry professionals and discuss their perceptions of the barriers to climate change adaptation. We conclude with several policy directions including reevaluating existing policies, expanding incentivebased policies, integrating adaptation efforts into mitigation efforts, and increasing communication and outreach.

Forest Development And Regeneration Dynamics In The Context Of Global Change And Associated Adaptation Strategies, Peter Clark

Graduate College Dissertations and Theses

Over the past century, forested ecosystems in northeastern North America have undergone significant changes characterized by the recovery from intensive land use and impacts from the introduction of invasive insects and disease. These changes, coupled with emerging threats posed by a changing climate present challenges to the maintenance and conservation of biodiversity, ecological functions, and delivery of critical forest ecosystem services. While management strategies to increase forest resilience and mitigate impacts from climate change have been broadly proposed, there are nascent empirical evaluations of their effectiveness. To address this uncertainty, this dissertation couples field manipulations with long-term measurements to examine …

Informing Adaptation Strategies For Northeastern Pitch Pine Barrens In The Context Of Mesophication And Southern Pine Beetle Impacts, Elizabeth-Ann Jamison

Graduate College Dissertations and Theses

Forest pests, the most significant agent of disturbance in forested ecosystems of North America, are highly sensitive to climate change. Southern pine beetle (SPB) is a highly destructive pine forest pest that is expanding its historic range in the southeastern US to affect the globally rare northeastern pitch pine barrens as winter temperatures warm. By generating high levels of mortality in canopy pitch pine, SPB is accelerating the ongoing conversion of fire-dependent pine barrens to mesophilic forests. We aimed to support the adaptive management of pine barrens ecosystems in the context of these two threats by (1) assessing stand conditions …

Soil Microbial Nitrogen-Transforming Genes Influenced By Tree Species And Fertilization In An Appalachian Hardwood Forest, Emma G. Fox-Fogle

Graduate Theses, Dissertations, and Problem Reports

Many forest ecosystems have been receiving elevated nitrogen (N) deposition due to human activity. Increased ecosystem N threatens soil fertility, water and air quality, and modifies the soil microbially-mediated N cycle in complex ways. The current study investigates how the abundance of key functional N cycling genes within soil bacteria is altered by N deposition and further mediated by different dominant tree species at the Fernow Experimental Forest, WV. Soils were analyzed from two watersheds, where watershed 3 (WS 3) has been receiving experimental applications of N fertilizer that are 2x historic ambient N deposition and 5x the current ambient …

The Impacts Of Asian Longhorned Beetle On Forests In Southern New England, Olivia Fay Box

Graduate College Dissertations and Theses

Over the past several decades, the United States has been experiencing an influx of nonnative pests due to increased globalization, and many of these pests have the potential to permanently alter the composition, structure, and function of forests. Asian longhorned beetle (ALB) is an invasive pest that came into Worcester county, MA in 2008, where the first instance of this species invading both urban and natural forested areas was documented. Within the quarantine area for this novel invasion, 30,000 trees were removed over the course of 10 years as part of management efforts focused on harvesting all host species, primarily …

Analyzing Safety Audits To Improve Logging Safety Performance, George Daniel Nolan Jr

Graduate Theses, Dissertations, and Problem Reports

This study examines logging safety audits to determine how different variables, and differing amounts of time between audits, affect the outcome of safety score performance. To collect the data for this study a three-page paper audit was used that examined five areas of the logging site which include: Personal protective equipment (PPE), general, felling, mobile equipment and, landing and loading.

The study analyzed 3 aspects of the audit which were the total score and the sub-categories of PPE and felling since they were the two heaviest weighted sections. The analysis only included audits that had a 5 percent or greater …

Post-Fire Effects In Chaparral And Oak Ecosystems Of Northern California, Abigail M. Jones

Cal Poly Humboldt theses and projects

The issue of wildfires, hazard fuels management, and post-fire tree mortality has become an increasingly common topic in the western United States. This thesis is composed of two studies, with the first study, Chapter 1, examining fuel treatment effectiveness and the second study, Chapter 2, striving to characterize post-fire mortality in oaks.

Prior to wildfire, fuel reduction projects may take place to decrease the likelihood of high severity fire around human infrastructure and communities. Within California’s chaparral ecosystems, common treatment types include hand-thinning, prescribed burning, mechanical mastication, and mechanical mastication followed with prescribed burning. Because chaparral has a longer historical …