Forest Sciences Commons^™

Quantifying The Ecological Effects Of Salix Fragilis On Riparian Habitat In Kittitas County, Washington, Landon Shaffer

All Master's Theses

Invasive species threaten plant community structure and function globally. Riparian areas, the zone near streams where water influences vegetation, are especially sensitive to invasive species colonization, suffering large-scale shifts in community composition. Salix fragilis (crack willow) is a nonnative riparian species abundant in the lower elevation tributaries of central Washington. Some speculate whether this willow should be listed as invasive in Washington, despite a lack of regional supporting evidence. I studied riparian communities dominated by either S. fragilis or native species in the Kittitas Valley and measured biodiversity, quantified differences in solar attenuation, and compared leaf decomposition rates to learn …

A Conservation Model: Costa Rican Conservation Strategies Effectively Preserve Their Threatened Primates, Ryan Belmont

Regis University Student Publications (comprehensive collection)

The wildlife of Costa Rica has experienced various anthropogenic threats over the last century including climate change and agricultural expansion. The mantled howler monkey (Alloutta palliata), Central American spider monkey (Ateles geoffroyi), white-faced capuchin (Cebus imitator), and the Central American squirrel monkey (Saimiri oerstedii) are Costa Rica’s native primates that face several anthropogenic threats such as deforestation for agriculture and climate change. In response to increased threats to its four native species of non-human primates, Costa Rica has implemented effective governmental conservation tactics such as the Payments for Environmental Services program, ecotourism …

Environmental Biology Masters Capstone, Antonio Gonzalez-Pita

Regis University Student Publications (comprehensive collection)

Human wildlife interactions (HWI) pose a complex challenge for wildlife managers. Human encroachment into wildlife habitat and the growing number of outdoor recreationists are increasing the frequency of contact and conflict, especially in regions such as the Front Range of Colorado. Geographic information systems (GIS), which use a combination of remote sensing and environmental survey data, allow for predictive spatial analyses of where human wildlife interactions are likely to occur. I used publicly reported observations of moose to create spatial predictive maps in a species distribution model framework. Slope and elevation were shown to be the strongest predictors of HWI, …

Regeneration Response To Salvage Logging Following Tornado Disturbance, Colby K. Bosley-Smith

Electronic Theses and Dissertations

In an era of increasing natural disturbances, successful tree regeneration has grown more difficult to achieve. Salvage logging, a common management response to disturbance, may further impede regeneration success, although published literature currently remains inconclusive. In 2013, a rare tornado in northcentral Maine, USA, and subsequent salvage operation created three clear ‘treatments’ for evaluation of post-disturbance regeneration: blowdown, blowdown followed by salvage logging and an undisturbed control. In the summers of 2022 and 2023, (nine and ten) years post-tornado, we revisited this site to examine regeneration outcomes.

During the summer of 2022, we evaluated stand structure and regeneration success of …

Germination Trends Of American Chaffseed, Schwalbea Americana L., And Factors Affecting First-Year Seedling Development, Trenton Miller

All Theses

Following centuries of exploitation and fire suppression, longleaf pine systems are now the focus of many conservation efforts. Efforts to restore populations of Schwalbea americana L. in longleaf pine savannas have been met with frustratingly low recruitment. While past studies have briefly quantified germination rates for Schwalbea, there have not been any studies yet that truly investigate this plant’s germination requirements. Additionally, there has been little research into characterizing the parasitic relationship between Schwalbea and its various host species. We conducted a germination study in a growth chamber that investigated Schwalbea’s germination rate and time to germinates as …

The Discovery Of A Novel Bacteria From A Large Co-Assembly Of Metagenomes, Matthew Finkelberg

Masters Theses

In the summer of 2022, a co-assembly of metagenome was created using the microbes found at Barres Woods in Harvard Forest. 14 samples were taken, and sample was split into the organic and mineral layer, which totals 28 Bulk MAGs. Within this Co-assembly, 4 different genomes were found which were designated with the phylum of FCPU426. Three of which were considered medium quality and one being assigned high quality. The novel phyla first appeared in NCBI and GTDB databases in June 2018. The name FCPU426 dates to 2010 and was named based on the 16s amplicon sequencing.

The novel phylum …

Climate Change Attitudes Of United States Family Forest Owners And Their Influence On Forest Management Practices, Logan Miller

Masters Theses

Understanding family forest owners’ (FFOs’) attitudes and behaviors towards climate change will allow for more sustainable forest management practices to be implemented, helping to combat climate change and its impacts. The goals for this research are (1) to begin measuring U.S. FFO attitudes toward climate change, (2) to determine what factors impact these attitudes, and (3) to determine how they influence the FFO’s management practices using the Responsible Environmental Behavior (REB) framework (Hines et al. 1987). Chapter 1 explores the different facets of my thesis project focusing on forests and forests’ ecosystem services, forest ownership in the United States, and …

Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry

Electronic Theses and Dissertations

Climate change is a threat to global forest ecosystems. In the northeastern United States, forest trees are facing rising temperatures and increasingly inconsistent moisture regimes. In addition to long-term changes in climate conditions, there is concern about the potential for more frequent and intense climate extremes, which can have severe and rapid negative effects on tree physiology and growth. Further, climate extremes may co-occur to produce a greater magnitude of effect than the sum of their parts, with a prominent example being hot droughts, which are increasing in occurrence and severity. The impact of these and other extreme climate interactions …

Effects Of Large Wood Additions On Basal Resources, Macroinvertebrates, And Ecosystem Processes In The Narraguagus River, Maine, Val Watson

Electronic Theses and Dissertations

Ecological restoration is an increasingly common practice across ecosystems, and current practices aim to restore the biological and physical processes underlying ecosystem function, often for the sake of endangered higher-level consumers. Studies of restoration outcomes often report few or inconsistent ecological changes, and monitoring of restoration projects rarely measures ecological processes. Monitoring also usually measures outcomes at a single scale, despite the prevalence of scale- dependent phenomena across ecosystems. My thesis uses measurements of ecological processes to assess restoration response and evaluates responses across multiple scales. I focus here on a long-term large wood addition project on the Narraguagus River …

A Four-Pronged Approach To Addressing A Wild Pig Invasion In A Bottomland And Upland Forested Landscape, Tyler Scott Evans

Theses and Dissertations

Among exotic species that are capable of invading, establishing, and reaching pest status, few pose the range of impacts to biotic (e.g., competition with native species, predation, herbivory, introduction of other exotics) and abiotic (e.g., soil, hydrology) ecosystem components that can be attributed to the wild pig (Sus scrofa). Despite the presence of wild pigs throughout the southeastern United States for centuries, new invasions continue to occur in previously uninhabited and often under-investigated landscapes, including bottomland and upland forests. The recent invasion of the Sam D. Hamilton Noxubee National Wildlife Refuge (hereafter, NNWR) in east-central Mississippi represents an …

Influence Of Abiotic Drivers And Plant Community Interactions On Bald Cypress (Taxodium Distichum) Seedlings: Implications For Restoration, Victoria Ellis

Biological Sciences Theses & Dissertations

Forested freshwater wetlands are valuable ecosystems that provide habitat for numerous species, sequester carbon, and act as sinks for excess water and nutrients. Historically, these ecosystems have been heavily degraded by anthropogenic activities leading to loss of ecosystem services and a desire to restore freshwater forested wetland habitat. Thus, science-backed approaches for the restoration of freshwater forested wetlands are necessary to ensure restoration goals are met. This body of research employed the Stress Gradient Hypothesis to test whether a multi-species planting approach using Juncus effusus (L.) (soft rush) could facilitate the survival of Taxodium distichum (L.) Rich. (bald cypress) seedlings …

Evidence Of Competitive Release Following Overstory Mortality In A Semi-Arid Piñon-Juniper Woodland, Corrie D. Gonzalez

Biology ETDs

Extreme temperatures and severe drought events have led to widespread tree mortality worldwide. In semi-arid regions of the Southwest United States, these events pose a significant threat to piñon-juniper (PJ) woodlands. We studied the effects of piñon and juniper mortality on the growth and physiology of existing saplings in PJ woodlands by analyzing water status, photosynthetic activity, and tissue chemistry to gain insights into these impacts. Juniper saplings exhibited improved water status and water use efficiency in response to overstory mortality, whereas piñon saplings did not. Additionally, both piñon and juniper saplings exhibited increased photosynthetic rates, increased photosynthetic capacity, and …

Considerations For The Use Of Mycorrhizal Fungi Inoculants In Coal Mine Reclamation And Reforestation In Appalachia: A Guide Of Best Practices And Management Recommendations, Cole Hansen Reistrup

Master's Projects and Capstones

Nearly all terrestrial plants form symbiotic relationships with mycorrhizal fungi. These beneficial soil microbes support plant health by increasing plants’ access to nutrients and water, protecting them from pathogens, improving soil properties, and more. A challenge to restoring forests on coal mined land in Appalachia is that mine soils are often degraded in a number of ways, including lacking mycorrhizal fungi, which makes mine soils difficult for trees to grow upon. Substantial improvements to coal mine reforestation success have been made since the development of the Forestry Reclamation Approach in 2005 that provides guidelines for how to create a suitable …

The Response Of An Avian Community To Intercropping And Forest Management Practices In A Private Working Pine Forest, Rebecca Doyne Bracken

Theses and Dissertations

Within managed pine forest systems, a plethora of bird species exist throughout the lifecycle of a stand akin to what may be experienced through post-disturbance regeneration in a natural forest system. I sought to address how breeding avian communities shift across time in response to stand aging and forest management, evaluate species-specific responses to stand conditions, investigate the responses of at-risk avian species to forest management, and determine avian non-breeding, over-wintering presence in a managed loblolly pine (Pinus taeda) forest. I conducted breeding bird point count and vegetation surveys within five stands of privately owned and managed pine forest in …

Pasturelands As Natural Climate Solutions: A Socioecological Study Of Tree Carbon And Beef Production Trade-Offs, Bela Starinchak

Masters Theses, 2020-current

Forest restoration is the most effective natural climate solution, with the potential to sequester 37% of the carbon dioxide (CO₂) needed to reach the Paris climate mitigation goal. Cattle pastures offer an underutilized opportunity to increase global forest restoration efforts, improve biodiversity, and maximize carbon storage through the adoption of management strategies that prioritize the incorporation of trees into pasturelands. However, remote estimations of tree carbon storage in pastoral systems have never been field-verified and their accuracy is unclear. Furthermore, the effect of increased trees on cattle production is understudied across biomes. Lastly, the restoration potential of these …

Top Down Effects And Resource Selection By Coyotes In South Carolina, Alex Jensen

All Dissertations

Top predators play important roles in functioning ecosystems, including regulating the populations of prey species and competing with other predators. However, in the face of global change, many top terrestrial predators have declined in both range and abundance, making room for some smaller predators to expand into new niches. Coyotes (Canis latrans) in North America are a prime example of this – they have rapidly expanded their range in the last 120 years, raising concerns about their impacts on both domestic and wild species. In eastern North America, research has centered around their effects on white-tailed deer ( …

Immediate Response Of Bats To Prescribed Fire And Impact Of Experiences On Women's Self-Image In Natural Resources Professions, Zebria Hicks

All Theses

To inform use of prescribed fire management practice in the southeastern US, we studied its impact on bats, which are important and at-risk species. We evaluated if prescribed fire had a positive, neutral, or negative effect on bat activity in the two weeks following the burns. We recorded bat activity after prescribed burns in February and March 2022 in northwestern South Carolina in select hardwood and pine stands and control sites ≥ 500 m from burn boundaries. We measured insect abundance, canopy cover, basal area, and understory density at each site. We recorded 687 passes during our 45-day study period. …

Competition And Herbivory Influence The Survival, Growth, And Physiology Of Native Tree Seedlings In The Kentucky Inner Bluegrass Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Terrestrial plant communities are shaped by competition for resources, herbivory, and abiotic processes. Savanna systems represent a dynamic coexistence of contrasting life forms (grasses and trees) shaped by competition and disturbance. The Kentucky Inner Bluegrass Savanna-Woodland (KIBSW) is described as an open woodland of shade intolerant species; however, climatic, and edaphic conditions can support closed-canopy forest. After European pioneer settlement (c1750-1800), over 99% of “savanna-woodlands” have been lost. KIBSW remnants are experiencing a recruitment failure, leading to a dominance shift in tree communities. I researched how tree-grass competition and mammalian herbivory influence KIBSW regeneration and maintenance. The KIBSW does not …

The Long-Term Effects Of Wildfire Severity On Oak-Pine Communities And Their Microclimates, Scott Glenn Culbert

Theses and Dissertations--Forestry and Natural Resources

In the eastern U.S., fire-dependent tree species have historically dominated upland forest communities, but are now experiencing widespread regeneration challenges as a result of 20^th century fire suppression policies, and are being replaced by mesophytic species. Wildfires that contain areas of high burn severity may provide an important means of mitigating these challenges and facilitating fire-dependent species regeneration and recruitment into larger size classes. One mechanism by which high-severity fire can accomplish this is by modifying understory microclimate characteristics to be more conducive to these species’ growth. A wildfire within the Daniel Boone National Forest, Kentucky, USA, provided the …

Pond-Breeding Amphibian Responses To Wetland Creation And Reforestation On A Legacy Surface Mine In The Monongahela National Forest, Lauren Breanna Sherman

Theses and Dissertations--Forestry and Natural Resources

Surface mine reclamation has been an evolving practice since the Surface Mining Control and Reclamation Act was passed in 1977, holding mining companies accountable for returning ecological function to areas directly impacted by mining activities. One recent method of reclamation, the Forestry Reclamation Approach (FRA), aims to enhance reforestation and ecosystem function through the creation of wetlands, as opposed to traditional methods that often revert land to grasslands. However, wildlife response to FRA has rarely been investigated. The goal of this project was to analyze the effects of the four treatment types, FRA in two chronosequences, natural regeneration, and unmined …

Fine Characterization Of Leafing Phenology In The Brazilian Atlantic Forest By Optical And Microwave Remote Sensing, James B. Bell

Dissertations and Theses

Tropical forests provide important ecosystem functions in the global biosphere, but they remain among the most poorly understood elements of land surface models, especially with regard to their seasonal dynamics. For instance, in seasonally dry forests, the pattern of the annual green-up in their canopies closely follows annual patterns of rainfall. The same, however, does not occur in wet forest canopies which are dominated by evergreen trees. In the latter, water is not scarce enough to limit leaf photosynthetic function. Canopy leafing phenology in these forests is therefore poorly characterized by optical remote sensing methods which are not sensitive to …

Forest Management In The Context Of Global Change: Impacts Of Disturbance, Adaptive Management, And Invasive Species On Northeastern Forests, Jennifer Santoro

Graduate College Dissertations and Theses

Climate change is predicted to have variable and uncertain effects on forested ecosystems globally. In the northeastern US, natural disturbances have historically been a central driver of forest successional dynamics, but as climate warming is projected to alter the frequency and severity of these events, post-disturbance management strategies to sustain biodiversity and ecosystem services must adaptively change to promote forest resilience. A suite of adaptive silvicultural actions has been proposed to promote forest resilience in the face of uncertainty, but due to the multi-decadal scale of forest management, initial field experiments are only beginning to show results. To address these …

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 …

Patterns, Mechanisms, And Characterization Of Carbon Cycling Stability Following Partial Forest Disturbance, Kayla C. Mathes

Theses and Dissertations

Among the most essential questions in the era of climate change is how the forest carbon (C) cycle will respond to an increase in the extent of biotic disturbances from insects and pathogens. While research has focused on stand-replacing disturbance regimes, less is known about C cycling stability following partial disturbances that produce gradients of disturbance severity. Belowground C cycling responses to disturbance are especially poorly understood, even though temperate forest soils contain up to 50% of total ecosystem C and soil respiration (R_s) accounts for more than half of temperate forest C loss. Interpreting trends and mechanisms …

White-Tailed Deer In A Winter-Wonderland: Long-Term Deer Yard Use And Methodological Considerations For Ungulate Fecal Dna Metabarcoding, Melanie A. Ottino

Dissertations, Master's Theses and Master's Reports

Northern white-tailed deer (Odocoileus virginianus) mitigate the increased energetic costs of severe winter conditions through obligate migration to densely congregated areas with abundant conifer cover, a behavior referred to as yarding. “Deer yards” in the Western Upper Peninsula (UP) of Michigan are principally located within the reduced snowpack and increased ambient temperature microclimates of densely canopied eastern hemlock (Tsuga canadensis) stands, but specific drivers of long-term site fidelity and utilization are largely uncharacterized. As an important game species of high economic and cultural value and a keystone herbivore with critical impact of plant community composition and structure, identifying winter yarding …

Buoyancy And Emergence In Elymus Species, Sandor Jakab

Williams Honors College, Honors Research Projects

It is important that native plants are able to successfully emerge in wetlands because they play an important role in maintaining diversity. The relationship between seed buoyancy and seedling emergence was analyzed for three wetland species of the same genus: Elymus canadensis (FACU), Elymus macgregorii (FACW), and Elymus virginicus (FACW). E. macgregorii seemed to be the most buoyant, and E. virginicus and E. canadensis demonstrated very similar, less buoyant levels. Based on the idea that more buoyant seeds will be deposited at a shallow depth, and less buoyant seeds will be deposited at a deeper soil level, a relationship between …

Quantitative Silviculture Of Northern Conifers, David G. Ray

Electronic Theses and Dissertations

Quantitative tools used to guide the management of important northern conifer species require updating and refinement to address changes in the contemporary resource and evolving objectives of ownership. This work builds on an extensive body of knowledge about stand density management and innovates some new approaches. In sum, the three chapters presented herein: 1) seek to strengthen and more fully articulate arguments for adopting relative density as a primary metric of stand density assessment, 2) quantify minimum stand densities to achieve full site occupancy and argue for more parity with treatment of maximum stand density, and 3) present an empirically …

Carbon Dioxide Emissions From Deadwood In Forests Of The Northeastern United States, Zoe Read

Electronic Theses and Dissertations

As the climate changes, understanding the sources and sinks of greenhouse gases such as carbon dioxide (CO₂) is increasingly important. However, several components of the carbon cycle within forests remain poorly understood. For example, knowledge gaps exist in our understanding of CO₂ emissions from coarse woody material (CWM; logs and stumps), including how emissions change over time, how they are influenced by environmental variables, and how they compare to soil and ecosystem-level CO₂ emissions.

To fill these knowledge gaps, we examined CO₂ emissions from CWM at three sites. We sampled 18 red spruce (Picea …

Vegetation And Nutritional Changes Over 20 Years Of White-Tailed Deer Exclusion, Gabrielle Nicole Ripa

Theses and Dissertations

Knowledge of the impacts of white-tailed deer (Odocoileus virginianus; hereafter deer) as dominant herbivores throughout the Southeastern United States of America is lacking. To address this, three paired experimental units of exclosures and controls were constructed in 2000 on three Wildlife Management Areas across Mississippi within the ecoregions of the Upper Coastal Plain, Lower Coastal Plain, and the Mississippi Alluvial Valley. Vegetation was sampled in the summers of 2000, 2005, and 2021 including vegetation structure, canopy coverage, basal area, and species composition. Additionally, in 2005 and 2021, biomass was sampled to determine potential impacts on nutritional carrying capacity. Among the …

Evaluating Current And Future Potential Distribution Of Epiphytic Orchids In The Congo Basin With Ecological Niche Models, Michael L. Ngoh

Masters Theses

The Congo Basin Forest harbors a rich diversity of epiphytic communities, with the Orchidaceae alone making up more than 50% of all epiphytes in the region. Despite the huge diversity of epiphytes, many species, including epiphytic orchids, are at risk to a diverse array of threats. Climate change for instance poses severe threats to epiphytic orchids due to elevated temperatures, prolonged periods of droughts, as well as reduced rainfall across the Congo Basin Forest. In this study, we used ecological niche modeling and GIS techniques to identify spatial patterns of species richness, potential future climate refugia, and novel climatic suitability …