Ecology and Evolutionary Biology Commons^™

Dynamic Patterns Of Resource Selection In Northern Bobwhite Across The Annual Cycle In A Region With Poor Edaphic Conditions, Autumn S. Randall

Theses and Dissertations--Forestry and Natural Resources

Developing successful management strategies requires an understanding of how an organism's resource needs change over the course of its life cycle. For almost a century, northern bobwhite (Colinus virginianus) populations have been declining range-wide, mostly as a result of habitat loss and degradation. Resource selection studies conducted at coarse-temporal resolutions and in areas with fertile soils form the majority of current management recommendations for bobwhites. In this thesis, we quantified resource selection patterns for 1,302 bobwhites in a region with poor soil conditions with respect to several common management practices (fire, fallow fields, supplemental feeding, and brush management …

Pcb Remediation In Transitional Floodplain Forests Along The Housatonic River, Soleil Laurin

Scripps Senior Theses

Human development affects natural environments in more ways than climate change, from the introduction of nonnative species and deforestation to pollution and urbanization. This is a case study examining the effects of PCB remediation on transitional floodplain forest along the Housatonic River in Western Massachusetts. The Housatonic River had previously been contaminated with PCBs and portions had been remediated. This study aims to determine the effects this remediation had on transitional floodplain forests, as well as provide a preliminary biodiversity assessment for sites that are planned to be remediated of PCBs by the Environmental Protection Agency. The study was carried …

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 …

Biology And Ecology Of Neonectria Magnoliae And Neonectria Punicea, Two Understudied Neonectria Species In West Virginia, Hannah Marie Petronek

Graduate Theses, Dissertations, and Problem Reports (ETD)

The family Nectriaceae includes numerous phytopathogenic fungi that cause canker diseases on both angiosperm and conifer hosts worldwide. Numerous Neonectria spp. cause cankers on hardwoods and conifers in North America, but their roles in contributing to tree decline and mortality outside of beech bark disease are largely understudied. One such pathogen, Neonectria magnoliae, causes perennial cankers on two native hosts in central Appalachia: Fraser magnolia (Magnolia fraseri) and tulip-poplar (Liriodendron tulipifera). We also recently confirmed N. magnoliae from non-native star magnolia (Magnolia stellata) in West Virginia. Both native hosts occur in the central …

Movement Behavior And Metapopulation Connectivity Of Stream Salamanders In Response To Disturbance Events, Kathryn M. Greene

Theses and Dissertations--Biology

Metapopulations are shaped by the dispersal between populations in a landscape. Disturbance events can disrupt this connectivity resulting in local population extinction. For my dissertation, I used a combination of empirical and theoretical techniques to examine dispersal in response to disturbance and assessed it’s population-level consequences. My research used capture-mark-recapture sampling techniques to evaluate stream salamander movement in response to (1) a supraseasonal drought and (2) mountaintop-removal-mining (MTR) and valley-filling (VF) and (3) agent-based simulation modeling to evaluate population extinction risk in response to varying dispersal and mortality rates.

First, I evaluated the effects of a supraseasonal drought, a severe …

Effects Of Climate Change On Seed Germination May Contribute To Habitat Homogenization In Freshwater Forested Wetlands, Kori Carr, Xavier Ozowara, Taylor M. Sloey

Biological Sciences Faculty Publications

Climate changes in temperate regions are expected to result in warmer, shorter winters in temperate latitudes. These changes may have consequences for germination of plant species that require a period of physiological dormancy. The effect of cold duration on seed germination has been investigated in a number of plant taxa, but has not been well studied in wetland and bottomland forest tree species, an ecosystem that is threatened by habitat homogenization. Our work sought to test the role of changing winter temperatures on seed germination in specialist (Nyssa aquatica and Taxodium distichum) and generalist (Acer rubrum and Liquidambar styraciflua) tree …

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 …

Automatic Detection Of Birds In Images Acquired With Remotely Piloted Aircraft For Managing Wildlife Strikes To Civil Aircraft, Maurycio Rodrigues Oviedo, Flavio A. C. Mendonca Ph.D., Jose Cabrera, Cole A. Mcnall, Raymond Ayres, Ricardo Luís Barbosa, Rodrigo Gallis

International Journal of Aviation, Aeronautics, and Aerospace

Wildlife strikes represent a significant threat to aviation safety and economics, as evidenced by notable incidents such as the emergency landing of US Airways Flight 1549 in 2009. The Federal Aviation Administration (FAA) acknowledges this growing concern, as evidenced by its report on Wildlife Strikes to Civil Aircraft in the United States from 1990 to 2019.To address the need for improved risk management, airports conduct Wildlife Hazard Assessments (WHA), a laborious process typically relying on visual identification by Qualified Airport Wildlife Biologists (QAWB). However, technological advancements, such as Remotely Piloted Aircraft (RPA) and machine learning (ML), offer promising solutions to …

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

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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 …

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 …

Forest Composition Change And Biophysical Climate Feedbacks Across Boreal North America, Richard Massey, Brendan M. Rogers, Logan T. Berner, Sol Cooperdock, Michelle C. Mack, Xanthe J. Walker, Scott J. Goetz

Aspen Bibliography

Deciduous tree cover is expected to increase in North American boreal forests with climate warming and wildfire. This shift in composition has the potential to generate biophysical cooling via increased land surface albedo. Here we use Landsat-derived maps of continuous tree canopy cover and deciduous fractional composition to assess albedo change over recent decades. We find, on average, a small net decrease in deciduous fraction from 2000 to 2015 across boreal North America and from 1992 to 2015 across Canada, despite extensive fire disturbance that locally increased deciduous vegetation. We further find near-neutral net biophysical change in radiative forcing associated …

Variation Of Carbon Stock Of Boca Del Drago Mangrove Forests Based On Salinity And Seaward Proximity, Fiona Wyrtzen

Independent Study Project (ISP) Collection

Mangrove forests, at the intersection of land and sea, are considered one of the most important marine environments for their variety of ecosystem services and their ability to sequester large amounts of carbon in their biomass and adjacent soils. With a changing climate, many of the abiotic and biotic factors influencing mangroves will begin to shift, potentially impacting resilience, growth capacity, and distribution of mangroves worldwide. This study aimed to examine the influence of changing salinity on the carbon stock capacity for Rhizophora mangle and Laguncularia racemosa forests, and the distribution of biomass in each species relative to salinity in …

Mycorrhizal Fungi Mediate Aboveground – Belowground Interactions In Forest Ecosystems, Amelia A. Fitch

Dartmouth College Ph.D Dissertations

The activities of plants and soil microbes are the primary drivers of forest ecosystem processes such as carbon (C) and nitrogen (N) cycling, and mycorrhizal fungi serve as a bridge between these two groups of organisms. The combined efforts of trees and associated mycorrhizal fungi to seek soil nutrients links C and N cycling through effects on saprotrophic communities and decomposition activity. In these studies, I investigated the effects of arbuscular (AM) and ectomycorrhizal (EcM) associations on microbial communities and ecosystem processes related to SOM decomposition and N cycling, and in turn how differences in soils beneath AM and EcM …

Alpha Diversity And Species Status Of Uneven Forests In Eco-Zones Of Taraba State, Nigeria, Dau Henry Japheth, Joseph A. Ugbe, Jerry I. Alfa

Journal of Bioresource Management

Alpha diversity indices quantify the uncertainty in predicting the species identity of an individual. Quantitative indices on species composition and distribution are vital to understanding the trend and species status of an ecosystem for conservation management. However, among the forest ecosystems in Taraba state, Bakin Dutse and Wasaji uneven forests are one of the least studied areas, especially in terms of tree species status. This research work aims at assessing alpha diversity and species status of selected uneven forests in Taraba state, Nigeria; to provide baseline knowledge for conservation management. In total, 102 tree species from 74 genera and 41 …

Genomic And Transcriptomic Analyses Reveal Polygenic Architecture For Ecologically Important Traits In Aspen (Populus Tremuloides Michx.), Jennifer F. L. Riehl, Christopher T. Cole, Clay J. Marrow, Hilary L. Barker, Carolina Bernhardsson, Kennedy Rubert-Nason, Pär K. Ingvarsson, Richard L. Lindroth

Aspen Bibliography

Intraspecific genetic variations in foundation species such as aspen (Populus tremuloides Michx.) shapes their impact on forest structure and function. Identifying genes underlying ecologically important traits is key to understanding that impact. Previous studies, using single-locus genome-wide association (GWA) analyses to identify candidate genes, have identified fewer genes than anticipated for highly heritable quantitative traits. Mounting evidence suggests that polygenic control of quantitative traits is largely responsible for this "missing heritability" phenomenon. Our research characterized the genetic architecture of 30 ecologically important traits using a common garden of aspect through genomic and transcriptomic analyses. A multilocus association model revealed …

Remote Sensing Characterization Of Ecosystem Structure And Functional Types To Inform On Biodiversity Conservation In The Lowland Chocó Rainforest, Derek Tesser

Dissertations, Theses, and Capstone Projects

This dissertation focuses on the utilization of remote sensing techniques to characterize ecosystem structure and functional types to inform on biodiversity conservation. This work is motivated by a guiding hypothesis that increased degradation of tropical forest biodiversity due to human activity results in in measurable changes in ecosystem processes that can be detected using remote sensing technologies. Throughout this dissertation, testing of aspects of this hypothesis involve comparing areas with varying degrees of human-induced degradation in a biodiverse tropical ecoregion, the lowland Chocó rainforest of Ecuador. Remote sensing data is used to evaluate changes in vegetation structure, thermal regimes, and …

Bison Alter The Northern Yellowstone Ecosystem By Breaking Aspen Saplings, Luke E. Painter, Robert L. Beschta, William J. Ripple

Aspen Bibliography

The American bison (Bison bison) is a species that strongly interacts with its environment, yet the effects of this large herbivore on quaking aspen (Populus tremuloides) have received little study. We documented bison breaking the stems of aspen saplings (young aspen > 2 m tall and ≤ 5 cm in diameter at breast height) and examined the extent of this effect in northern Yellowstone National Park (YNP). Low densities of Rocky Mountain elk (Cervus canadensis) after about 2004 created conditions conducive for new aspen recruitment in YNP's northern ungulate winter range (northern range). We sampled …

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 …

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 …

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 …

Variable Synchrony In Insect Outbreak Cycling Across A Forest Landscape Gradient: Multi-Scale Evidence From Trembling Aspen In Alberta, Barry J. Cooke, Jens Roland

Aspen Bibliography

Using multi-scale trembling aspen tree-ring width data from Alberta, we show that scaling has a profound influence on dendroecological inferencing. At all scales of sampling, there is a significant climatological signal whose strength is nevertheless superseded by the pervasive effect of insect herbivory. At the smallest spatial scale, 20 km x 20 km, we demonstrate a quasi-periodic pattern of sharp growth reductions and the existence of negative spatial correlations among successive outbreaks. At the intermediate spatial scale of 20 km x 80 km, we show that the period 1930-1963 was marked by extremely low correlations in aspen ring widths, with …

Do Species Matter? Examining The Niche Of White Ash (Fraxinus Americana L.) And Estimating Potential Subcanopy Effects Of Its Loss In North-Temperate Forests, Elizabeth Anne Studer

Dartmouth College Ph.D Dissertations

To understand the downstream consequences of the extinction of a species, we must understand its role in an ecosystem. With the impending extirpation of ash (Fraxinus spp.) due to the invasive emerald ash borer (Agrilus planipennis), understanding the role of ash trees is critical to predicting whether its loss will precipitate further species declines and/or ecosystem functions. We evaluated whether subcanopy microbial, invertebrate, and floral communities under four tree species (white ash, American beech, yellow birch, sugar maple) and on two soil hydropedological types (Bh podzol and Typical podzol) varied in species richness, composition, and functional traits in a factorial …

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald T. Garrett

Theses and Dissertations

Though the rate of deforestation has slowed in recent years, it remains a primary cause of land cover change within forest ecosystems. The Lower Rio Grande Valley, Texas (LRGV) has lost nearly 95% of its native thornforest since the early 1900’s due to agricultural and urban expansion. The focus of this study is to assess the current vegetative state of restored thornforest sites located in the eastern LRGV and to evaluate the use of cover crops during replanting of native seedlings. Our assessment of restored thornforest sites revealed actively restored sites demonstrated higher overall averages of richness, abundance, and diversity …

Comparisons Of Above- And Below-Ground Carbon Storage In A Northeastern Illinois Urban Forest Following Rhamnus Cathartica And Fraxinus Spp. Removal, River Sanchez-Dudik, Elene Drosos

DePaul Discoveries

This study focused on quantifying potential differences in ecosystem services (carbon storage, soil organic matter, macroarthropod density) in a small, partially restored urban forest in order to determine if common buckthorn and standing dead ash removal effects can be detected while restoration is on-going. We calculated aboveground carbon storage (tons/total area) using whole tree biomass equations and compared this to i-Tree Canopy estimations. We collected SOM through loss-on-ignition and collected macroinvertebrates by pitfall trapping to determine differences along transects. Aboveground carbon storage, soil organic matter, and macroinvertebrate total results for this study were found to be statistically not significant, indicating …

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 …

Willow Abundance And Condition Mapping In Rocky Mountain National Park, Eric M. Nielsen

Institute for Natural Resources Publications

Riparian and wetland willow species have undergone serious declines in Rocky Mountain National Park as a consequence of a variety of environmental changes and, most recently, damage resulting from moose overpopulation. To address concerns about the long-term status of willows in the park, we developed remote sensing-based raster maps of riparian and wetland willow species presence, canopy cover percentage, canopy height, and leaf area index. All outputs were produced at 3-meter resolution, and represent willows as they existed in 2021. The mapping was performed via random forests classification and regression models trained on several hundred vegetation plots from a variety …

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 …