Digital Commons Network^™

Do Talus Slopes Provide Hibernacula Resources For Bats In Maine? Site Charecteristics Associated With Winter Occupancy And Sampling Design, Christopher C. Heilakka

Electronic Theses and Dissertations

In Maine, the decline of cave dwelling bats has been caused by the fungal disease commonly known as white-nose syndrome discovered in 2006. Northern long-eared bats (Myotis septentrionalis), little brown (Myotis lucifigus) andeastern tricolored bats (Perimyotis subflavus) have experienced 95% or greater population declines, and eastern small-footed (Myotis leibii) and big brown bats (Eptesicus fuscus) have also declined. In Maine, talus slopes, or piles of sloped rocks found at the base of cliffs, are widely distributed and past research has suggested talus as a potentially important, but previously unrecognized, class …

Classifying The 2022 Status Of Tsuga Canadensis (Eastern Hemlock) Along The Kentucky Portion Of The Pine Mountain Wildlands Corridor., Grace M. Embree

Electronic Theses and Dissertations

The invasion of the Hemlock Woolly Adelgid (HWA) (Adelges tsugae) has posed a continual threat in the United States to the Eastern Hemlock (Tsuga canadensis) trees since the 1950s. HWA feed on eastern hemlock needles, reducing the amount of healthy photosynthesizing vegetative area. The use of satellite imagery has been instrumental in identifying areas of eastern hemlock presence. Satellite platforms like Landsat and AVIRIS are commonly used for identification, classification, and mapping of eastern hemlock. Sentinel-2 imagery was released in 2015 for free access. It has a finer spatial grain of with the majority of the …

Detection, Occupancy, Abundance, And Mercury Accumulation Of The Alligator Snapping Turtle (Macrochelys Temminckii) In Texas, David Rosenbaum

Electronic Theses and Dissertations

Land use practices and physical alterations of ecosystems result in habitat loss and fragmentation, while chemical alterations, such as pollutant input, reduce habitat quality and health of exposed organisms. Here, I investigated the effects of watershed- and local-scale environmental variables on the occupancy, abundance, and mercury accumulation of a threatened aquatic species (Macrochelys temminckii, i.e., alligator snapping turtle) within the southwestern periphery of its distribution. Hierarchical modeling suggested the distribution of the species is more affected by watershed-scale land-cover than local habitat, and provided a baseline estimate of average species abundance across its range in eastern Texas. Abundance …

Plant-Pollinator Communities Responsive To Local And Landscape Level Factors In Grassland Restorations., Aaron Sexton

Electronic Theses and Dissertations

As humans continue to degrade natural ecosystems via greenhouse gas emissions and habitat destruction, many species are being pushed to the brink of extinction. In hopes to offset this degradation, habitat restoration attempts to restore ecosystem function to an improved state resembling intact, remnant values. This is a difficult, but important, undertaking with factors to consider at multiple spatial and temporal scales. The restoration and conservation of pollinator communities has garnered heightened attention because of the valuable ecosystem services they provide. This dissertation investigates the local and landscape level factors of grassland restorations that influence plant-pollinator communities. I used a …

Responses Of Arthropods To Fire And How Pollinators And Pollination Services Are Affected By Fire Severity, Blyssalyn V. Bieber

Electronic Theses and Dissertations

Fires impact ecosystems globally and due to climate change, there are shifts in fire regimes that impact ecological communities which provide essential ecosystem services. Focusing on arthropods, fire can influence this ubiquitous animal group in various way. We performed a comprehensive meta-analysis evaluating how fires impact differing arthropod functional groups. We found that overall, fire negatively effects community level responses for most functional groups with herbivores as the only exception showing some positive effects of fire. We also studied mixed-severity fires that burned >20 years ago and compared floral visitor communities across fire severities. We implemented a pollinator exclusion experiment …

-Rhiza., Katherine E. Watts

Electronic Theses and Dissertations

-rhiza is a collection of work that focuses on an immersive experience of local ecology and the dichotomous relationship of humanity and nature, presented through the artist's eyes, ecophilosophy, mycology, ecofeminism, and metaphor. An installation of experiential work, -rhiza consists of videography, printmaking, photography, musical elements, both found object and natural item sculptures, and poetry. This compendium of work addresses humanity's apathy towards the ecological imbalance and how this affects our fundamental interconnectedness with all life. Based on explorations of local waterways and the recognition of human consumerism's pressing issues, -rhiza attempts to present the urgent matter of rising …

Present In Presence, Lyndsey A. Frantz

Electronic Theses and Dissertations

My ceramics are made to entice the viewer to live in their present moment by altering their perception and familiarity of utilitarian objects through means of natural processes found out in nature. I want the user to be fully engaged with thoughts about time, nature, and being present during their lives. Life in not just about daily responsibilities and sometimes we as humans can get so caught up in everything around us that we simply forget to enjoy everything we have worked hard to achieve. By experiencing something new, we can get out of our comfort zones and being present …

Measuring The Success Of A Coastal Sand Dune Restoration On Tybee Island: Plant Growth, Sand Accretion, And Implications For Management, Shannon Matzke

Electronic Theses and Dissertations

Coastal communities are developing rapidly in the face of increased risks of sea level rise and hurricanes stemming from anthropogenic climate change. In the US, erosion is projected to cost $530 million/year in property loss, but beaches and dune systems can minimize these losses. Dunes are vital to coastal protection, particularly when they are colonized by native plant species that stabilize sand with their root systems and accumulate sand by trapping particles with their stems and leaves. Dune construction can be used as a nature-based solution to climate change, but more studies are needed to fully understand the best practices …

Residency, Diel Movement, And Tidal Patterns Of Large Juvenile Bull Sharks (Carcharhinus Leucas) In Winyah Bay, Sc, Jeremy Lee Arnt

Electronic Theses and Dissertations

No abstract provided.

Responses Of Juvenile Atlantic Salmon To Competition And Environmental Change: Implications For Performance In Maine Streams, Nicole C. Ramberg-Pihl

Electronic Theses and Dissertations

New England’s climate is changing faster than that of any other region in the continental United States. Over the last century, Maine has experienced an increase in annual temperature of approximately 1.48^oC along with a 15 percent increase in annual precipitation. Temperature and precipitation play vital roles in shaping the ecology of freshwater environments. Therefore, changes in regional climate could undermine the structure and stability of Maine’s freshwater systems as they currently exist.

Maine currently harbors the last wild populations of Atlantic salmon (Salmo salar) in the United States. Atlantic salmon were once abundant in Maine …

Congruence And Temporal Variation Of Floral Visitation And Pollen Transport Networks In Southern Appalachia, Daniel A. Barker

Electronic Theses and Dissertations

Observation of floral visitation is an accepted method to describe plant-pollinator interactions despite potential biases. Collecting pollen from pollinators offers new insights on the structure and function of plant-pollinator communities. Furthermore, the strength and frequency of plant-pollinator interactions can vary across temporal scales. However, within-season and within-day (morning vs. evening) variation in plant-pollinator networks has been little studied. By evaluating variation in network structure across these biologically relevant time scales, we will gain a better understanding of the factors that shape plant-pollinator communities. The objectives of this study are to 1) Compare the structure of plant-pollinator networks built on floral …

"Wand'ring This Woody Maze": Deciphering The Obscure Wilderness Of Paradise Regained, Brooke Johnson

Electronic Theses and Dissertations

The setting of Milton’s great sequel is puzzling, being called a desert and a “waste wild” (IV. 523) repeatedly and at the same time including descriptions of protective oaks and woody mazes. These conflicting descriptions conjure up several questions: In which environment does the epic take place? Because Milton is so detailed in his adaptations of biblical narrative the inclusion of trees is quite perplexing. While he does tend to expand biblical narrative quite frequently – e.g. Paradise Lost – he rarely initiates a change without just cause. The crux of this particular change centers on what this just cause …

Chronoecology Of A Cave-Dwelling Orb-Weaver Spider, Meta Ovalis (Araneae: Tetragnathidae), Rebecca Steele

Electronic Theses and Dissertations

Circadian clocks enable coordination of essential biological and metabolic processes in relation to the 24-hour light cycle. However, there are many habitats that are not subject to this light cycle, such as the deep sea, arctic regions, and cave systems. This study analyzes the circadian pattern of isolated populations of a subterranean spider, Meta ovalis from two Tennessee caves and five Indiana caves. Locomotor activity was recorded with TriKinetics LAM50 Locomotor Activity Monitor under a 12-hour light (L), 12-hour dark (D) (LD 12:12) cycle preceding total darkness (DD). Significant differences were found within and among populations found in Tennessee cave …

Land Use Influences Along Elevation Gradient On Macroinvertebrate Communities, Brittany Sprout

Electronic Theses and Dissertations

Land use activities have caused disturbances that affect the quality of freshwater ecosystems worldwide. How the influences of land use along an environmental gradient and the associated environmental variables that may influence stream diversity and function is unclear. We address these issues by studying biodiversity, abundance, and functional diversity of macroinvertebrates across different land types along a gradient in Colorado, USA. We also address how diversity may change along an elevation gradient by analyzing previously published macroinvertebrate research. We found evidence that land use and disturbance are stronger explanations of changes in macroinvertebrate communities, rather than elevation. Functional trait patterns …

Bacterioplankton Biogeography Of The Mississippi River Basin, Jason Taylor Payne

Electronic Theses and Dissertations

Bacterioplankton are important structural and functional components of river networks yet their biogeographical patterns in these systems are largely unknown. Using Illumina sequencing of the 16S rRNA gene we characterized variation in bacterioplankton community alpha diversity (within-sample richness of operational taxonomic units OTUs) and beta diversity (between-sample differences in composition) (1) along a 1 300-km downstream reach of the Mississippi River (2) over a range of temporal scales in the Lower Mississippi River (LMR) and (3) along cross-sectional transects repeated monthly for six months across the LMR floodplain. Particle-associated assemblages were richer in bacterial OTUs and more productive than free-living …

Simulations And Modelling For Biological Invasions, Ryan D. Scott

Electronic Theses and Dissertations

Biological invasions are characterized by the movement of organisms from their native geographic region to new, distinct regions in which they may have significant impacts. Biological invasions pose one of the most serious threats to global biodiversity, and hence significant resources are invested in predicting, preventing, and managing them. Biological systems and processes are typically large, complex, and inherently difficult to study naturally because of their immense scale and complexity. Hence, computational modelling and simulation approaches can be taken to study them. In this dissertation, I applied computer simulations to address two important problems in invasion biology. First, in invasion …

The Population Ecology And Behavior Of The Cave Salamander, Eurycea Lucifuga (Rafinesque, 1822)., Joseph Gavin Bradley

Electronic Theses and Dissertations

The Cave Salamander, Eurycea lucifuga (Rafinesque, 1822), is a little-known species, yet a common inhabitant of caves in the eastern United States. Salamanders are often important components of ecological communities and ecosystems, influencing critical processes such as nutrient cycling and community composition through their predation on invertebrates. Cave-dwelling salamanders such as E. lucifuga may thus appreciably influence the relatively simple ecosystems and communities of caves. Any such influence may be particularly important because these habitats and the organisms that reside in them are often of conservation concern. I used non-invasive methods to study the demographics, movements, and habitat selection of …

Movement In Cats, Valerie N. Plummer

Electronic Theses and Dissertations

Feral cats (Felis catus) are listed as one of the '100 world's worst invasive alien species'. There are as many as 70-100 million feral cats in the United States as well as an estimated 117-157 million domestic indoor and outdoor cats. Management efforts include a nonlethal feeding and sterilization program known as "trap-neuter-release" (TNR) where cats are surgically sterilized and returned to the environment. Population size and structure, immigration rates, spay/neuter rates, and data on spatial use all play a role in whether TNR is a viable management option. This study focuses on population structure and spatial use. …

Vegetation Community Changes In Two National Forests In The Pineywoods, East Texas, Trisha L. Williams

Electronic Theses and Dissertations

Despite extensive research into forest succession, little research has been directed to long-term studies. The fundamental properties of succession remain unclear and further research into terrestrial vegetation and an accounting of drivers in specific ecosystem types is required. This study addresses change in plant communities from five ecosystem types in two east Texas National Forests over a 20-year period. An analysis of 30 sample stands yields results due to various ecosystem drivers of vegetation change and uncovers plant community responses in multiple ecosystem types over this period. This research provided three key results: 1) that vegetation composition change occurs more …

Transversal Approaches And Ecological Artwork., Madison Deanna Sevilla

Electronic Theses and Dissertations

This work explores systematic ecology as it relates to sculpture and language. This project exists in two parts: a written thesis and a thesis exhibition. Although both works explore ecological systems, Unseen: Visualizing Ecological Systems investigates visualizations and concepts of the ecological, whereas this thesis continues the exploration into the ramifications of disruptions in systems. Ecological systems such as the environmental, social/mental, economic, and political define the foundations of our known world and encapsulate all regions of society. No single system can function independently of the rest and all systems contain some aspect of human-system involvement. By using the work …

Phenotypic Plasticity Of Native And Invasive Cool-Season Grasses In Response To Frequency Of Moisture Availability, Ming-Yu Stephens

Electronic Theses and Dissertations

Phenotypic plasticity, the ability of an individual to alter its growth in response to environmental conditions, is an attribute that is considered a likely invader attribute, as it provides the opportunity to expand its ecological niche breadth. Adaptive phenotypic plasticity can affect not only the ability to establish in a new environment, but also the ability to outperform the existing vegetation over time. Bromus inermis (smooth brome) and Poa pratensis (Kentucky bluegrass) are invasive species in tall- and mixed-grass prairie ecosystems. The objectives of this two-part study were to quantify the adaptive plasticity of biomass accumulation and tiller production in …

Cultivating Ecological Literacy And Rethinking Our Connections To Nature, Sean Fretwell

Electronic Theses and Dissertations

In this dissertation I explore the complex, often contested, relationships between humankind and nature. I consider the changing state of these relationships as they are influenced by factors rooted in science, technology, and economics. I also examine these relationships as they relate to human activities with agriculture. Considering the present state of environmental crisis and the abundance of evidence indicating the deleterious activities of humankind as primary causes for the many global calamities, I argue for revising industrially-driven ideologies; particularly those driven by the economic paradigm of capitalism and self-interest. Additionally, I submit that a return to kinship with nature …

Ecological Niche Modeling Of The North American Giant Salamander: Predicting Current And Future Potential Distributions And Examining Environmental Influences, Selena S. Roark

Electronic Theses and Dissertations

North American Giant Salamanders (Cryptobranchus alleganiensis), commonly known as hellbenders, have been experiencing a population decline for decades due to human influences, such as pollution and habitat destruction. Many efforts are underway to save the hellbender but their entire potential geographical range has not been well-studied. Currently, hellbender populations are delineated by county boundaries and are on the International Union for Conservation of Nature Red List. The Genetic Algorithm for Rule-set Production, an Ecological Niche Model, was used to model the current hellbender potential distribution at a macro-scale under two different environmental scenarios. Additionally, future potential distributions were …

An Examination Of Plant Community Composition In Six Carolina Bays On The Coastal Plain Of South Carolina, Katherine L. Altman-Goff

Electronic Theses and Dissertations

Historically high rates of human impact and recent Supreme Court cases, which have affected the regulation of geographically isolated wetlands in the United States, suggest that Carolina bays may be at high risk of human impacts in the future. Conservation efforts should be established based on applied ecological data and, if regulations by state and federal agencies are unable to conserve Carolina bay wetlands, it may be important to prioritize individual bays for preservation on protected lands. I examined plant community composition, diversity, richness, and rarity and soil parameters in six Carolina bays across South Carolina, using a replicated ecological …

Variation In The Amphibian Hypothalamic Pituitary Adrenal Axis: Patterns, Mechanisms, And Implications, Jessica Thomas

Electronic Theses and Dissertations

Many vertebrate stress responses are mediated by the hypothalamic-pituitary-adrenal/interrenal (HPA/I) axis, which involves hypothalamic secretion of corticotropin releasing factor (CRF) and increased plasma levels of glucocorticoid hormones (GCs) like corticosterone (CORT). Basal HPA/I activity is also imperative to maintaining homeostasis. Despite having crucial roles, HPA/I activity is variable and can be influenced by factors like environment, physiology, and life-history. HPA/I activity also influences reproduction and immunity. To better understand patterns of HPA/I variation (specifically CORT and CRF), we conducted several studies using plethodontid salamanders. Their low-energy lifestyle offers unique contrast to studies of stress physiology in high-energy animals like mammals …

"Discursion And Excursion:" Poetry Of Bodies, Place, And Landscape In The Ecocritical Movement, Haley N. Littleton

Electronic Theses and Dissertations

My thesis project focuses on the current literary field of Ecocriticism, its historical transmutations, and the correlation of the pastoral genre, as one begins to understand current human understandings of "nature." By applying a deeper understanding of the Deep Ecology movement, along with shifting understandings of the human and the non-human, specifically in our usage and attention to landscape and wilderness, I hope to explore the role that the aesthetic, and the function of the poem, can play a crucial role in the environmental movement. By building a foundational understanding of our cultural context and critical theories of Environmental criticism, …

Niche Breadth And Invasion Success, Harri Pettitt-Wade

Electronic Theses and Dissertations

A developing concept in ecology is that broad niches predict geographical range size. Plasticity in resource use is often considered to be important for responding to novel environments, and study of species that are established across different ranges provides a model for determining the drivers of species spread and distribution. Contrasting distributions of invasive species are often associated with species-specific feeding ecology, but comparisons are rarely made for multiple taxa, spatial scales or between native and invaded ranges.

Is Colorado Buddhism Green? A Study Of The Interaction Of Buddhist Practice With Environmental Concerns, Mengye Liu

Electronic Theses and Dissertations

The human community is paying more attention to our growing environmental crisis. Religious beliefs are often proposed as effective ways to address environmental ethics. It is often supposed that Buddhism is a "green" religion because of its intimate associations with nature. My research focuses on whether or not Buddhism in Colorado influences Buddhist practitioners' environmental awareness by identifying and evaluating Buddhist ecological attitudes and values. My research questions include: (1) what aspects of Buddhist practice refer to the elements of natural environment, (2) do Buddhist practitioners profess different attitudes and behaviors than non-Buddhist practitioners, and (3) If so, how does …

Spatial And Habitat Responses Of Canada Lynx In Maine To A Decline In Snowshoe Hare Density, David G. Mallett

Electronic Theses and Dissertations

Previous studies of Canada lynx (Lynx canadensis) within the northern boreal forest region have documented that lynx respond spatially to a decline in snowshoe hare (Lepus americanus) density, as exhibited by expansion of territories and changes in social structure. I compared home range area and spatial overlap in the southeastern portion of their geographic range during periods of relatively high and relatively low hare density. Home range areas of lynx did not change between periods of high and low hare density, except that home ranges of females during the denning season expanded during the low period. The presence of kittens …

Effects Of Mechanical Habitat Disturbance On The Diversity And Network Structure Of Plant-Bee Interaction Networks In Central Florida, Karlie Carman

Electronic Theses and Dissertations

Ecological interactions within a community shape the structure of ecosystems and influence ecosystem function. Plant-pollinator interactions exist as mutualistic exchange networks that may collapse as habitat loss occurs, thereby threatening the overall health of an ecosystem. Understanding the impacts of human-mediated habitat disturbance on ecological interactions is therefore crucial for conservation efforts. Archbold Biological Station (ABS) in Venus, Florida contains over 2000 hectares of protected Florida scrub habitat nested within a human-dominated environment that is threatened by anthropogenic habitat disturbance. In past studies, over 113 bee species and 157 associated host plants, many endemic to the Lake Wales Ridge, have …