Other Ecology and Evolutionary Biology Commons^™

Exploring The Effects Of Pest-Induced Hemlock Mortality On Growth In Neighboring Trees, Sidney L. Booher

McNair Culminating Research Projects

Trees provide many important products and services to humans. In particular, tree growth is critical to carbon storage, air and water quality, and helps determine demographic processes like population growth and reproductive success. Importantly, tree growth is sensitive to both abiotic (environmental) and biotic factors and is vulnerable to ecological disturbances. Understanding how tree populations respond to disturbances, like invasive pests, is therefore crucial to formulating timely and effective forest management practices.

Here, I used tree ring analysis to investigate how competition for water between neighboring trees changes following the decline of Eastern and Carolina Hemlock(ECH) trees due to the …

Leaf Droppage Delayed In Sugar Maple Trees On An Urban To Rural Gradient, Isabella S. Bastien, Isabella Bastien

The Cardinal Edge

This study investigates the timing of leaf abscission in Sugar Maple (Acer saccharum) trees along an urban-to-rural gradient in Louisville, Kentucky, to determine how proximity to urban environments influences leaf drop. We hypothesized that urban trees would retain their leaves longer than suburban or rural trees due to environmental stressors and tested this using weekly leaf collection and canopy cover measurements from three locations—urban, suburban, and rural. Results showed that urban trees exhibited delayed leaf drop and slower canopy opening compared to suburban and rural trees. These findings suggest that urban stressors significantly alter tree phenology, which may signal underlying …

Ectomycorrhizal Fungi Associated With Pinus Species Of California's Northwestern Coast, Monika Audrey Richardson

Cal Poly Humboldt theses and projects

Ectomycorrhizal (ECM) fungi are vital for increasing host plant uptake of nutrients and stress tolerance within ECM forest ecosystems. The species assemblage of ECM fungi can vary locally in response to numerous biotic and abiotic environmental factors. In California’s northwestern coast the occurrence of three Pinus species, along with a disjunction between populations of Pinus muricata in Mendocino and Humboldt Counties, offer a unique opportunity to investigate the spatial and host effects on pine-associated ECM fungi. Ectomycorrhizal fungal community structure was quantified from host tree roots and sequenced sporocarps occurring at the same sites to create a project specific ITS …

Green Connectivity In Metropolitan Jabodetabek: Climate Change And The Challenge Of Urban Forest, Safira Maharani Putri, Hendricus Andy Simarmata

CSID Journal of Infrastructure Development

Urban areas in Indonesia, particularly the Greater Jakarta metropolitan region (Jabodetabek), are increasingly experiencing the adverse effects of climate change, such as the Urban Heat Island (UHI) phenomenon. Rapid urbanization has contributed significantly to rising greenhouse gas emissions and deteriorating environmental quality. Urban forests are one of the key solutions to mitigate these impacts; however, their spatial distribution in Jabodetabek remains suboptimal and poorly connected. This study uses NDVI as a proxy for urban forest density, where “urban forest” refers to vegetated areas within cities as defined by Presidential Regulation No. 60/2020. The research addresses the following question: How has …

The Ecology Of Arthropod Rain In A Tropical Forest., Andrew Robert Seiler

Electronic Theses and Dissertations

Tropical forests are structured by complex vertical linkages and nutrient exchanges between canopy and understory habitats. These linkages include the downward flux of organisms, the movement of canopy fauna, and the recycling of nutrients through litter and organic matter deposition. This dissertation investigates arthropod rain and its role in connecting the canopy and forest floor processes in a lowland tropical forest in Panama. Chapter 2 quantifies “arthropod rain”, the fall of canopy arthropods into the understory. Using pan and pole traps, I measured the composition, abundance, and biomass of arthropods falling from the canopy and assessed environmental drivers of the …

Pollinator Plant Communities Within Restored Montane Longleaf Pine Ecosystems, Hanen Van Rossem

Master's Theses

Historically the fire-dependent and biodiverse longleaf pine (Pinus palustris) ecosystem was the dominant ecosystem of the Southeastern US. This ecosystem’s range was massively reduced due to land conversion and fire exclusion, causing the decline of many native species. Efforts to restore and protect longleaf pine stands are now ongoing with the goal of expanding habitat and refuge for threatened species. Differences in restoration practices and prior land use may influence the extent to which restored habitat patches can support pollinators and their plants. This study compared pollinator plant biodiversity between restored neighboring montane longleaf pine stands that differed in …

Life After Death: Investigating The Resistance And Recovery Of Fungal Communities To Foundation Tree Mortality, Jessie F. Marlenee

Biology ETDs

Tree mortality can have cascading effects on the composition and resilience of interacting fungal communities. Yet, little is known about the impact tree mortality, distinct from abiotic drivers (i.e., drought), has on these communities. This dissertation focuses on the resilience of fungal communities to experimental tree mortality in a piñon-juniper woodland. In chapter one, I found that piñon mortality reduced piñon fine root biomass and piñon mycorrhizal fungal diversity, whereas juniper mycorrhizal fungi were unaffected by juniper mortality. In chapter two, I revealed that piñon mortality altered the composition and spatial structure of mycorrhizal and saprotrophic fungi in the soil, …

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 …

Chinese Tallow Long-Term Impact On Stand Dynamics In A Bottomland Hardwood Forest Following Vegetation Management, Nicklaus R. Langlois

Electronic Theses and Dissertations

Chinese tallow (Triadica sebifera (L.) Small) is an invasive tree known to have negative impacts on bottomland hardwood forests. Chinese tallow is proficient in reproducing and surviving in bottomland hardwood forests because it is more flood and shade tolerant than most native trees. The long-term effectiveness of Chinese tallow control is an important topic to research as only a few long-term studies of Chinese tallow control have been conducted. A 10-year re-measurement of 22 paired plots installed in 2012 on the Pineywoods Mitigation Bank near Diboll, Texas following herbicide treatments examined Chinese tallow and native tree stand structure. Each …

An Ecology Against The Right. Learning Uncertainty And Humility From Ecosystems, Pierre L. Ibisch, Mona Eikel-Pohen, Elias Iceman, Jake Snelling

Languages, Literatures, and Linguistics - All Scholarship

This article is a translation from the German to English. The title of the original is:

Ibisch, P.L. (2020): Eine Ökologie gegen rechts. Von Ökosystemen Unsicherheit und Demut lernen. In: Leitschuh, H., A. Brunnengräber, P.L. Ibisch, R. Loske, M. Müller, J. Sommer & E.-U. v. Weizsäcker (eds. J. Sommer, P.L. Ibisch, A. Brunnengräber): Ökologie und Heimat. Jahrbuch Ökologie 2021. Hirzel-Verlag, Stuttgart, 191-205.

Sense Of Place In Natural Resource Recreation And Tourism: An Evaluation And Assessment Of Research Findings.

The International Journal of Ecopsychology (IJE)

No abstract provided.

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, …

The Role Of Neighborhood Effects In Maintaining The Hardwood-Hemlock Mosaic, Adam Z. Milenkowic

Dissertations, Master's Theses and Master's Reports

Neighborhood effects are processes mediated by canopy trees that influence the ability of a species to replace itself following canopy mortality. Sugar maple (Acer saccharum Marsh.) and eastern hemlock (Tsuga canadensis (L.) Carr.) are the dominant trees in old-growth northern hardwood forests of Upper Michigan and have been observed to form monodominant patches in the region. Few studies have independently evaluated the demographic and ecological mechanisms that lead to the compositional stability of hemlock and sugar maple patch development. Tree demography data from eight long-term 0.5 ha old-growth plots in Upper Michigan indicate neighborhood effects are playing a …

Leaf To Canopy Functional Resilience: Plant Physiological And Carbon Cycling Stability Following Disturbances, Lisa T. Haber

Theses and Dissertations

Ecological disturbances impact core ecosystem functions, including production and biogeochemical cycling, by precipitating changes in biodiversity, physical environmental variables, vegetation structure, and functional trait distributions. As disturbance patterns intensify and abruptly transition to novel regimes under global change, future trajectories of ecosystem functions, including carbon (C) uptake and storage, are uncertain. A more complete understanding of the mechanisms underpinning ecosystem stability (or ability to return to baseline functioning) following disturbance is needed to forecast future C cycling.

Replicated ecosystem-scale disturbance experiments, particularly when coupled with modeling, are required to rigorously test hypothesized trajectories of ecosystem structural and functional change following …

Integrating Western Science And Indigenous Knowledge For Just Practices In Conservation, Cierra Lea Keith

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

Quantifying The Influences Of Abiotic And Biotic Factors On Post-Fire Vegetation In The Southwestern Us, Joseph Lafayette Crockett

Biology ETDs

The ongoing warming associated with climate change is increasing the flammability of southwestern US dry forests. As larger fractions of the landscape are impacted by high-severity fire, the potential exists for forests to convert to non-forest. Given that the forested area in the southwestern US is an important contributor of ecosystem services, quantifying limitations to vegetation establishment is critical to informing post-fire recovery efforts and understanding how ongoing climate change will limit seedling establishment in the future. To that end, this dissertation focuses on post-fire vegetation recovery of southwestern forests. First, I report on the influence of precipitation and topography …

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 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 …

Effect Of Variable Canopy Cover On Floral Visitation, Toby Shaya

2023 Midwest Ecology & Evolution Conference

Pollinators provide essential services for ecosystem function. Studies aimed at understanding how availability of floral resources impacts pollinators find that canopy cover impacts bees indirectly by affecting the amount of floral resources in the forest understory and directly by changing the thermal environment in which they can thermoregulate. As ectotherms the maintenance of bee body temperature depends on the distribution of patches of sun and shade throughout a landscape, which can be dependent on canopy cover. The goals of this study were to understand how variable canopy cover drives floral visitation patterns in oak savanna found in the Oak Openings …

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 …

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 …

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 …

Assessing Priority Bird Response To Open Pine Management In Eastern Mississippi, Holly Marie Todaro

Theses and Dissertations

Fire suppression, combined with lack of forest thinning and short-rotation, monodominant management, has drastically altered the landscape in the southeastern U.S., leading to the loss of open pine ecosystems and associated avian species. Management of open pine ecosystems is a common practice; yet, there remains uncertainty regarding how vegetation structure impacts priority species. Using empirical data, I assessed changes in species abundance and associated vegetation characteristics before and after management. I also sought to identify vegetation characteristics that influence home range establishment and microhabitat selection of Bachman’s Sparrows. Priority species were negatively associated with hardwood midstory and abundance per site …

Spatiotemporal Factors Affecting The Occupancy And Phenology Of A Declining Songbird (Bachman's Sparrow - Peucaea Aestivalis) At The Western Extent Of Its Range, Liam G. Wolff

Electronic Theses and Dissertations

The Bachman’s Sparrow (Peucaea aestivalis) is a declining songbird that occurs throughout the southeastern United States. Bachman’s Sparrow is a Species of Greatest Conservation Need in Texas, but information crucial to management efforts, such as factors affecting their detectability and occupancy, is lacking. I investigated the predictors of Bachman’s Sparrow occupancy and phenology in Texas using detections from autonomous recording units coupled with site characteristics and weather data. My results indicate that Bachman’s Sparrow occupancy is associated with increasing herbaceous ground cover and decreasing basal area, distance to the nearest source population, and basal area when canopy height …

The Role Of Leaf Decomposition In Macroinvertebrate Colonization, Bethany Mabel Lian Schorr, Kevin Geedey

Independent Research Projects

Decomposition plays an important ecological role in carbon and nutrient cycling that supply food and energy resources to food webs. This study investigates the potential role that leaf decomposition of different leaf species may play in macroinvertebrate assemblages in upper Midwest streams. We hypothesized that the different decomposition rates experienced with different leaf species and in different streams would have an effect on invertebrate colonization due to the variance in nutrient availability. Due to altered fire regimes and other influences, forests are experiencing declines in fire-adapted, heliophytic species such as oaks and compositional shifts toward shade-tolerant, mesophytic species such as …

Mark-Recapture Study And Habitat Assessment For The Northern Metalmark Butterfly, Calephelis Borealis (Lepidoptera: Riodinidae), Weston J. Henry, Kristian S. Omland, Henry Frye, Wagner L. David

EEB Articles

Background: The northern metalmark (Calephelis borealis), is an exceedingly local, globally rare butterfly that is declining across the Midwestern and Northeastern USA. The principal stressors driving colony losses include afforestation and invasive plants that crowd out its larval hostplant (Packera ovata) and nectar resources.

Aims/Methods: To better understand its declines and guide restoration efforts, we 1) performed a mark-recapture study in Connecticut to document population trends where we were actively managing vegetation; 2) conducted a range-wide survey for evidence of phylogeographic structure, using cytochrome oxidase (CO1); 3) investigated abundance determinants of its larval foodplant, Packera ovata …

A Comparison Of Wildfire Adaptive Traits In Juvenile Conifers Of The Northern Rockies, Andie Sonnen

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Wildfire is an importance disturbance that continues to shape the ecosystems of the northern Rockies through varying patterns of frequency and intensity. Due to historical fire suppression and the hotter and drier conditions brought upon by anthropogenic climate change, wildfire frequency and intensity is increasing. These increases will alter vegetation structure and composition, but the degree to which is unknown.

Individual plant traits can offer insight into how these vegetation communities will shift, especially the particular traits that reduce fire-related mortality. To survive wildfires, juvenile northern conifers employ two strategies: increasing their bark thickness and increasing their crown height. To …

Coupled Structure-Function Responses To Disturbance: High Structural Complexity Resistance Supports Primary Production Resistance, Kerstin M. Niedermaier

Theses and Dissertations

The capacity of forests to resist structural change and retain material legacies–the biotic and abiotic resources that persist through disturbance–is crucial to sustaining ecosystem functioning after disturbance. However, the role of forest structure as both a material legacy and feature supporting carbon (C) cycling stability following disturbance has not been widely investigated. We used a large-scale disturbance manipulation to ask whether LiDAR-derived canopy structures as material legacies drive 3-year responses of NPP to a range of disturbance severity levels. As part of the Forest Resilience Threshold Experiment (FoRTE) in northern Michigan, USA we simulated phloem-disrupting disturbances at a range of …

Effects Of Dissimilar Silvicultural Techniques On Small Mammal Communities In Michigan's Upper Peninsula, Breanna R. Gusick

Dissertations, Master's Theses and Master's Reports

Small mammal populations, and predators reliant upon them as food resources, are often challenged by conflicting objectives of timber production and maintenance of quality habitat. With over 70% of the landscape forested, and nearly one-third of the land privately owned, Michigan’s Upper Peninsula (UP) is a matrix of independent management strategies. To assess the effects of various silvicultural regeneration methods on small mammal populations in the Upper Peninsula, we trapped small mammals in experimental silviculture plots, whereby treatments varied by regeneration method (amount of residual canopy cover) and site preparation (i.e., control, tip-up, and scarification), and deer exclosures. We used …

Invasive Earthworms In The Crown Of The Continent System And Implications For Land Management, Meghan Elizabeth Scott

Graduate Student Theses, Dissertations, & Professional Papers

The United States contains invasive earthworms originating from Europe and Asia; the majority are European lumbricids. Direct introduction occurs primarily through human activity and, once established, earthworm populations are difficult to address. When exotic earthworms engage in bioturbation, they negatively alter subterranean food webs and nutrient cycling by disrupting soil layering systems. The most prominent form of physical alteration is the change and removal of the topmost organic layer. This disruption is associated with altered nitrogen and carbon cycling, as well as altered forest floor plant communities.

The Crown of the Continent ecosystem is located in southwestern Alberta, southeastern British …