Life Sciences Commons^™

Top-Down And Bottom-Up Effects On Collembola Communities In Soil Food Webs, Jordan Kustec

Electronic Thesis and Dissertation Repository

Anthropogenic changes are causing shifts within soil food web communities, which may alter ecosystem processes such as nutrient cycling, carbon storage and decomposition. I quantified ecological stressor effects on the abundance, richness, community composition and body size of a soil-dwelling microarthropod (Collembola: Hexapoda). I quantified the effects of warming and nitrogen deposition in two separate field studies and demonstrated that warming shifts Collembola community structure and decreases community body size. I quantified the interactive effects of top-down and bottom-up forces mediated by warming as ecological stressors in Collembola communities. I found that bottom-up effects of nutrient addition did not affect …

Fall Migration And Winter Habitat Use Of Northern Saw-Whet Owls (Aegolius Acadicus) In The Ozark Highlands, Mitchell L. Pruitt

Graduate Theses and Dissertations

Studying movement ecology is important not only in understanding the distribution of a species, but in understanding the magnitude of migration through certain regions, as well as explaining regional differences in demographics. The Northern Saw-whet Owl (Aegolius acadicus) is a small, migratory forest owl found throughout much of North America. Despite being captured widely during fall migration, the species’ movement ecology is poorly understood. Exploratory studies outside the saw-whet owl’s normal range have successfully captured the species during fall migration. In the Ozark Highlands ecoregion of the central United States, their status has been considered vagrant during fall and winter. …

Where Are All Of Arkansas' Chinquapins? An Ecological Assessment Of Castanea Throughout The State, Logan Pierce Estes

Graduate Theses and Dissertations

Around the turn of the twentieth-century, the chestnut blight fungus (Cryphonectria parasitica) was accidentally introduced into North America. This strong pathogen, which specializes on trees of the genus Castanea, spread rapidly and within half a century had nearly extirpated North America’s Castanea natives from their ranges. During this catastrophe, the American chestnut (Castanea dentata) garnered much of the scientific attention, pushing the other Castanea natives – the chinquapins – to the wayside. More than a century following the spread of the blight, little research into the ecology of North America’s chinquapins had been performed, leaving these trees significantly underrepresented. The …

Behavioral Thermoregulation And Thermal Mismatches Influence Disease Dynamics In Amphibians, Erin Louise Sauer

USF Tampa Graduate Theses and Dissertations

Amphibians are currently the most threatened vertebra taxa on the planet. Hundreds of species are thought to have gone extinct while thousands more have been listed as threatened or endangered over the past few decades. Habitat loss, invasive species, climate change, and disease are all thought to have partially contributed to these declines. Two pathogens in particular, infectious viruses in the genus Ranavirus (simply referred to as ranavirus) and the fungus Batrachochytrium dendrobatidis (Bd), have been associated with global mass mortality events of amphibians. Virulent pathogens such as these tend to impose strong selective pressures on their hosts driving the …

Impacts Of Natural And Anthropogenic Colonized Habitats On The Range Shifting Mangrove Tree Crab (Aratus Pisonii), Zachary John Cannizzo

Theses and Dissertations

Mis-matches in climate-mediated shifting rates cause the ranges of some species to become decoupled from their historic ecosystem, leading to the colonization of ecosystems they have not previously inhabited. When this occurs, the shifting species may experience suboptimal conditions which challenge its ability to persist and expand into the novel ecosystem. However, within the colonized ecosystem, shifting species may encounter artificial habitat analogues: artificial habitats that more closely resemble the species’ historic ecosystem than the surrounding habitat and which mitigate some of the negative impacts experienced elsewhere in the novel ecosystem. Despite their importance to the ecology, life history, and …

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 …

Woodpeckers In The City: Habitat Use And Minimum Area Requirements Of Woodpeckers In Urban Parks And Natural Areas In Portland, Oregon, Adam Baz

Dissertations and Theses

Urbanization has contributed to the fragmentation and alteration of natural habitats around the globe, and is rapidly increasing. In this context, forested parks play a critical role for many species by providing patches of usable habitat within the urban matrix. Such patches may be particularly valuable to forest-specialists like woodpeckers (Picidae). Yet many woodpeckers require large forest patches, which are limited in fragmented landscapes. Despite their recognized value as ecosystem engineers and keystone species, almost no research exists on woodpecker ecology or space-use in urban settings. What habitat components influence woodpecker abundance and what are their functional minimum area requirements …

The Effects Of Gopher Tortoise (Gopherus Polyphemus) Herbivory On Plant Community Composition And Seed Germination, And The Effects Of Gut Passage On The Germinability Of Seeds: A Meta-Analysis, Jason C. Richardson

USF Tampa Graduate Theses and Dissertations

Herbivory produces direct and indirect effects on plants and at different spatial scales will have varied consequences. Consumption of plants by vertebrate grazers may affect the plants on an organismal level through direct mortality, on a community level by changing species composition or by altering the rate of succession, and even at a whole ecosystem level by altering nutrient cycles.

The majority of the scientific literature has focused extensively on herbivory by mammals and birds. With regard to mammals, studies have shown how folivory affects individual plants, plant populations, and communities of plants.

Mammals, as well as birds, also ingest …

Modified Landscapes, Esther Nooner

Graduate Theses and Dissertations

Modified Landscapes is a body of work that reflects serious thought regarding Nature and its future. My personal experience and beliefs are at the core of why I believe this subject to be of great importance and why it will sustain many artists’ investigations for the time to come. The influences that informed this process are explored through experiences I had traveling, reading and exploring the photograph as a material object. The manipulation of the photograph is meant to question the beautiful, untouched scene and break the Romantic gaze that is historically tied to representations of Nature and insist upon …

Spatial And Temporal Dynamics Of Batesian Mimicry Between Adelpha Californica And Limenitis Lorquini, Louis Albert Prusa

University of the Pacific Theses and Dissertations

Conspicuous coloration is one of the main ways that animals communicate. The use of eye-catching color patterns to warn predators of an unprofitable trait is referred to as aposematism. Once predators learn to recognize the color pattern, a new signaling niche becomes available where other species can share the same signal. This mimicry niche can involve a “hide in plain sight” strategy by mimicking or parasitizing this signal, with mimics lacking the defense and associated costs that make them unprofitable. This is termed Batesian mimicry, and it decreases predation by taking advantage of the memory and learning of the predator …

Should I Stay Or Should I Go? Complex Environments Drive The Developmental Plasticity Of Flight Capacity And Flight-Related Tradeoffs, Jordan R. Glass

University of the Pacific Theses and Dissertations

Animals must balance multiple, fitness-related traits in environments that are complex and characterized by co-varying factors, such as co-variation in temperature and food availability. Thus, experiments manipulating multiple environmental factors provide valuable insight into the role of the environment in shaping not only important traits (e.g., dispersal capacity or reproduction), but also trait-trait interactions (e.g., trade-offs between traits). We employed a multi-factorial design to manipulate variation in temperature (constant 28°C vs. 28±5°C daily cycle) and food availability (unlimited vs. intermittent access) throughout development in the sand field cricket, Gryllus firmus. We found that fitness-related, life-history traits and trait trade-offs can …

Ms Environmental Biology Capstone Project, Alyssa Herrin

Regis University Student Publications (comprehensive collection)

The study of visitor use in museums, zoos, and aquariums is an important aspect of understanding visitor engagement and evaluating the function of the institution. Here, visitor demographics such as age, group size, and number of children were assessed to see their influence on time spent and number of stops visitors made while visiting the Denver Botanic Gardens in Denver, Colorado. This study evaluated differences in time spent and number of stops made among different gardens by observing visitors and mapping their paths and activities through each zone. The results show that older visitors and larger groups spent more time …

Effects Of Nutrient Addition And Two Invasive Plants On Wetland Methane Production, Jaymes Dempsey

Senior Honors Theses and Projects

Wetlands provide a number of important ecosystem services, but their anoxic conditions also favor the production of several greenhouse gases. Wetlands are an ideal environment for methanogenesis, the process by which carbon dioxide is reduced to methane by wetland microbes (methanogens). As wetlands are the largest natural contributor to the atmospheric methane pool, it is important to understand variables that control wetland methane production. Nitrogen availability is one variable that likely affects methanogen communities. Nitrate drains from agricultural areas, where wetlands act as a nitrogen sink, preventing nitrate from contaminating aquatic systems. Another factor that may affect wetland methanogenesis is …

Camera Traps In Wildlife Research: Through My Lens, Bryson P. Allen

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Wildlife species can be difficult to study because they can have very large ranges and can be wary of observers. Researchers have been using camera traps in recent decades as a way to study wildlife behavior and population metrics. Here I explore the history of these tools in wildlife biology, their possible applications, and limitations.

Investigating The Ecology Of A Rare Species On St. John, Usvi: Reintroducing Solanum Conocarpum In Light Of Climate Change, Cecilia Rogers

Senior Honors Projects, 2010-2019

Approximately two thirds of St. John is National Park territory. However, the land has been threatened with tourism and development, greatly impacting island biodiversity. One species that may become extinct due to this degradation is Solanum conocarpum. S. conocarpum is a rare shrub, endemic to the dry tropical forests of St. John, USVI. This plant is a species of conservation concern and is one of very few native and endemic plants on this island. Very little is known about the ecology and reproduction of S. conocarpum. Most plants are found on the southern half of the island. Recent observations …

The Missing Metric: An Evaluation Of Microorganism Importance In Wetland Assessments, Aaron John Onufrak

Browse all Theses and Dissertations

In the contiguous US, an estimated 50% of original wetland areas have been lost since the late 1700s. In growing recognition of the importance of preserving wetland ecosystem function, federal and state agencies have developed proxy-based functional-assessment procedures to manage and preserve remaining wetland areas. Ohio uses the Ohio Rapid Assessment Method (ORAM) to score wetland quality based on six metrics: wetland size, buffer width and surrounding land use, hydrology, habitat alteration and development, special wetland communities, and vegetation. Currently, the ORAM, and many other wetland scoring systems, do not consider microorganisms when determining wetland quality. This is particularly notable, …

Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White

Theses and Dissertations (Comprehensive)

In recent years, climate warming has led to an increase in the severity and frequency of naturally occurring fires in boreal ecosystems globally. In 2014, an unprecedented 3.4 million hectares of boreal forest burned in the Northwest Territories (NWT). While much research has focused on post-fire succession of serotinous tree species such as Picea mariana (black spruce) and Pinus banksiana (jack pine), the understory community of vascular plants play an important role in ecosystem functioning but less is known about the response of this component of the system to changing fire regimes. Regeneration strategies such as the ability to resprout …

Lonicera Maackii Alters Decay Dynamics Of Coarse Woody Debris, Michaela J. Woods

Browse all Theses and Dissertations

Since industrialization, anthropogenic carbon emissions have led to excess atmospheric carbon dioxide that may alter the stability of ecosystem processes. Microorganisms are essential in mitigating excess carbon and play a notable role in the breakdown of organic material. This process, decomposition, is essential in forested ecosystems where microorganisms can recycle nutrients and store carbon in soil organic matter or release it through respiration. Fungi participate in decomposition through the release of enzymes responsible for carrying out the chemical reactions that break down plant material. Species introductions have the potential to alter decomposition dynamics. In the Midwestern US, the invasive shrub …

Comparing Created And Natural Depressional Wetlands Through Trophic Analysis Of Macroinvertebrates, Shante N. Eisele

Browse all Theses and Dissertations

Macroinvertebrates are important contributors to wetland ecosystems due to their role in decomposition, nutrient cycling, and as a food resource for other organisms. Several studies have analyzed the macroinvertebrate communities in created wetlands, but few have evaluated them in the context of trophic structure in both created and natural wetlands. The objective of this study is to better understand benthic macroinvertebrate community composition and trophic structure in created and natural wetlands. My central hypotheses were that macroinvertebrate communities in created wetlands would have (1) differing composition and (2) less complex trophic structure with shorter food-chain length compared to natural wetlands. …

Monitoring Ohio Bat Communities And Populations Using Mobile Acoustics, Molly C. Simonis

Browse all Theses and Dissertations

The goal of my thesis is to: 1) provide baseline information of where Ohio bats are foraging in Wright State University's (WSU) campus woods in relation to forest age and habitat (Chapter 1), 2) determine potential roost availability for local bats (Chapter 1), and 3) examine changes in state-wide species composition following the introduction of White-nose Syndrome (WNS; Chapter 2). In Chapter 1, I created walking bat acoustic routes and used generalized linear models to determine what forest ages and habitats had the greatest bat activity in the WSU campus woods. I conducted habitat transects throughout all forest ages to …

Forest Structural Complexity And Net Primary Production Resilience Across A Gradient Of Disturbance In A Great Lakes Ecosystem, Lisa T. Haber

Theses and Dissertations

Forests are an important component of the global carbon (C) cycle and contribute to climate change mitigation through atmospheric C uptake and storage in biomass and soils. However, the forest C sink is susceptible to disturbance, which modifies physical and biological structure and limits spatial extent of forests. Unlike severe, stand-replacing disturbances that reset forest successional trajectories and may simplify ecosystem structure, moderate severity disturbances may instead introduce complexity in ways that sustain net primary production (NPP), leading to the phenomenon of “NPP resilience.” In this study, we examined the linkage between disturbance severity and ecosystem biological and physical structural …

Evaluation Of The Stream Function Assessment Methodology (Sfam) In Watersheds Of The Puget Sound Lowlands, Michelle Bahnick

WWU Graduate School Collection

Effective stream management requires identification of anthropogenic degradation effects on stream functioning. However, few stream assessment protocols aim to evaluate stream functions (i.e., ecosystem processes), integrate multiple disciplines, and combine stream reach assessment with landscape-level context. To address these shortcomings, several agencies in Oregon collaborated to develop the Stream Function Assessment Methodology (SFAM). However, SFAM has yet to be tested against established protocols and some SFAM metrics have no equivalent data sources outside of Oregon. I conducted SFAM (2015 draft version) on 36 stream reaches in Water Resource Inventory Area 8 in Washington State. I compared SFAM scores to commensurate …

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. …

The Value Of Animal Behaviour As A Bio-Indicator Of Restoration Quality, Floyd Holmes

Theses: Doctorates and Masters

Woodland restoration is a complex endeavour, and restoration ecology as a scientific discipline requires constant re-assessments and adjustments if it is to improve outcomes and better provide for biodiversity. The promise of effective restoration is often used to justify destructive processes that affect many of the world’s ecosystems. It is therefore imperative that those promises can be met, which comes down to restoration ecologists’ and land managers’ capacity to predict and facilitate desirable ecological changes in a timely and socio-economically responsible manner. As perspectives have changed, and knowledge has been gained over the past few decades there have been several …