Biodiversity Commons^™

Novel Microbial Guilds Implicated In N2o Reduction, Guang He

Doctoral Dissertations

N₂O is a long-recognized greenhouse gas (GHG) with potential in global warming and ozone depletion. Terrestrial ecosystems are a major source of N₂O due to imbalanced N₂O production and consumption. Soil pH is a chief modulating factor controlling net N₂O emissions, and N₂O consumption has been considered negligible under acidic conditions (pH <6). In this dissertation, we obtained solids-free cultures reducing N₂O at pH 4.5. Furthermore, a co-culture (designated culture EV) comprising two interacting bacterial population was acquired via consecutive transfer in mineral salt medium. Integrated phenotypic, metagenomic and metabolomic analysis dictated that the Serratia population excreted certain …

Natural Resource Decisions: Discount Rates, Time Horizons, And Evaluations, Amanda Hyman

Doctoral Dissertations

As effects from climate change accelerate, there is a pressing need for research that can improve people’s lives and safeguard the environment. Billions of dollars are invested annually in such projects. To invest that money wisely, we need to understand the effects of assumptions that underpin decisions but often go unstated, such as assumptions about discount rates and time horizons. We also need to understand how project design choices affect the management of natural resources, prioritization of conservation actions, and success of climate adaptation projects. My dissertation explores these topics. I ask if and how local natural resource users and …

Broadscale Outcome And Monitoring Assessment To Evaluate Protected Area Effectiveness In Northern Patagonia, Maria Daniela Rivarola

Doctoral Dissertations

Biomes worldwide have been affected by biodiversity loss and habitat degradation for more than a century. Protected Areas (PAs) have been established in almost every country, as they represent one of the most important tools in biodiversity conservation. Nevertheless, the relentless biodiversity loss trend has not stopped. Concern about PA effectiveness has risen, and several methods to evaluate it have been implemented over the last few decades. Nahuel Huapi National Park (NHNP) is the first PA in Argentina and one of the largest. The area is considered a biodiversity hotspot, and its conservation is essential, as unique ecological and evolutionary …

A Systematic And Biogeographic Study Of Trillium (Melanthiaceae), Jayne A. Lampley

Doctoral Dissertations

Trillium (Melanthiaceae, Parideae) has a disjunct distribution occurring in eastern and western North America, and eastern Asia. Past studies have examined the phylogeny and historical biogeography of Melanthiaceae and Parideae, however these studies either did not fully examine these aspects within Trillium or did not employ sufficiently broad taxonomic or character sampling to clarify relationships among taxa. The first phylogenetic analysis presented in this study provides a resolved phylogeny for Trillium s.l. and Paris s.l. by using a dataset of 70 plastid coding genes and by sampling broadly from Trillium s.s., Pseudotrillium, Trillidium, Paris s.s., Daiswa, and Kinugasa. The results …

Birds And Bioenergy: A Modeling Framework For Managed Landscapes At Multiple Spatial Scales, Jasmine Asha Kreig

Doctoral Dissertations

This dissertation examines the design and management of bioenergy landscapes at multiple spatial scales given numerous objectives. Objectives include biodiversity outcomes, biomass feedstock yields, and economic value.

Our study examined biodiversity metrics for 25 avian species in Iowa, including subsets of these species related to ecosystem services. We used our species distribution model (SDM) framework to determine the importance of predictors related to switchgrass production on species richness. We found that distance to water, mean diurnal temperature range, and herbicide application rate were the three most important predictors of biodiversity overall. We found that 76% of species responded positively to …

Social-Ecological Systems Considerations For Wildlife Reintroduction And Conservation, Cristina Elisa Watkins

Doctoral Dissertations

Wildlife management, especially projects requiring reintroduction, are complex undertakings requiring interdisciplinary approaches. This dissertation combines social science, ecology, economics, and policy to advance wildlife reintroduction science and improve conservation outcomes. The central focus of this dissertation involves wildlife reintroduction management, with a specific emphasis on the reintroduction of elk into East Tennessee. The dissertation is divided by three studies, each taking a unique interdisciplinary approach to wildlife reintroduction. The first study uses structural equation modeling to examine the social psychology constructs of risk perception and trust to examine their influence on attitudes towards reintroduced elk in Tennessee and support for …

Systematics And Biogeography Of The Cortinarius Violaceus Group And Sequestrate Evolution In Cortinarius (Agaricales), Emma Harrower

Doctoral Dissertations

Phylogenetics is a powerful tool used for illuminating the diversity of life on Earth, their evolution and their ecology. I created a multi-gene phylogenetic tree of Cortinarius section Cortinarius and uncovered five previously overlooked species, increasing the number of species in the section from seven to twelve. All members of the clade possess both cheilocystidia and pleurocystidia and possess a pigment known as (R)-39,49-dihydroxybphenylalanine. Ancestral state reconstruction estimated that the ancestral host was most likely an angiosperm, switching hosts when encountering novel host species in new lands, and only C. violaceus associating with the Pinaceae in North America. Biogeographic analysis …

Conservation Decisions: Designing, Financing And Fundraising For Protected Areas, Rachel Elizabeth Fovargue

Doctoral Dissertations

Establishing protection for conservation is a complicated process that involves many critical decisions, from spatial prioritization to garnering the necessary financial support to complete a project. In my research, I address questions that inform various components of this process. First, I ask questions about protected area design using a case study of a large reef system in Australia. I find that simple design rules can facilitate the pursuit of conservation and extractive management goals. Second, I address questions about costs incurred by the financing of new protection. I establish a unique dataset of projects financed by a conservation non-profit through …

Detection, Diversity, And Evolution Of Fungal Nitric Oxide Reductases (P450nor), Steven Adam Higgins

Doctoral Dissertations

Nitrous oxide (N₂O) is a gas responsible for significant ozone layer depletion and contributes to greenhouse effects in Earth’s atmosphere. N₂O is primarily generated by denitrification, whereby nitrate (NO_3-) or nitrite (NO_2-) is converted to gaseous N₂O or N2. Teragram quantities of N₂O are emitted annually from agricultural soils treated with nitrogenous fertilizers due to the activity of soil microbiota. Although bacteria and fungi harbor genes permitting denitrification, fungi lack NosZ, an enzyme responsible for reducing N₂O into inert N2 gas. Historically, scientists have linked fungi …

Systematics, Diversification, And Functional Diversity Of Russulaceae (Russulales), Brian Patrick Looney

Doctoral Dissertations

The family Russulaceae is an iconic family of mushroom-forming Basidiomycetes both because of their importance as edible mushrooms in many parts of the world and their species richness in both temperate and tropical forested biomes. While much mycological research has been focused on this group, recent systematic and ecological research has failed to develop a comprehensive or cohesive organization by which to understand the evolutionary relationships, patterns of diversification, or functional importance of the group. Recently, interest in ectomycorrhizal fungi (EmF), of which Russulaceae is a key lineage, has greatly increased due to the recognition of the importance of EmF …

Regeneration Of Imperiled Hardwoods In The Eastern United States, Joshua J. Granger

Doctoral Dissertations

Our ability to successfully promote forest stand health and facilitate species under the threat of extinction will hinge on our ability to identify species regeneration requirements in an ever-changing environment. In the first chapter of this dissertation, I address what is known about the nature of threatened and imperiled hardwoods in the eastern United States, and in doing so, I identify several large knowledge gaps in current potentials and methodologies for regenerating them. In my second chapter, I use recent data from the United States Forest Service, Forest Inventory and Analysis program (FIA) to quantify ash regeneration counts across FIA …

Using Phylogenetic Comparative Methods To Understand Diversification And Geographic Range Evolution, Kathryn Aurora Massana

Doctoral Dissertations

Two key processes that have been modeled in a phylogenetic comparative framework are diversification and historical biogeography. Many questions arise on what process have shaped the abundance (or lack) of species we see today and what influences their survival and interconnectedness with other species. Many methods have been developed to answer these questions. Over the past several decades there has been a rise in parametric modeling and development of more adequate frameworks to answer biological questions of interest. However, many models still lack the incorporation of ecological, mainly biotic factors, which influence the evolution and ecology of species, while accounting …

Systematics, Diversity And Evolution Of The Suborder Tricholomatineae (Agaricales), Marisol Sanchez Garcia

Doctoral Dissertations

The suborder Tricholomatineae is one of the several major groups of Agaricales, the largest order of mushroom-forming fungi. This suborder contains three families: Tricholomataceae, Entolomataceae and Lyophyllaceae, as well as many genera of incertae sedis. Members of the Tricholomatineae exhibit variation in nutritional mode, including mycoparasites, saprotrophs, termite-associates, bryophyte parasites, and ectomycorrhizal (ECM) symbionts, which makes the clade ideal for studying trophic evolution in fungi from a phylogenetic perspective.

This dissertation combines taxonomy and evolutionary analyses to contribute to the knowledge of fungal diversity and mycorrhizal evolution. First, I present a systematic revision of the family Tricholomataceae within a …

Individual Variation In Plant Traits Drives Species Interactions, Ecosystem Functioning, And Responses To Global Change, Quentin Daniel Read

Doctoral Dissertations

Ecologists have long sought to understand the processes that lead to the riotous diversity in communities of organisms that inhabit disparate climates and landscapes. Such a diversity of traits leads to a diversity of interactions among species in natural communities, which in turn generates a diversity of potential responses to ongoing global change. In this dissertation, I do three things: I explore the forces that structure plant communities and the ecosystem functions that they mediate, I describe patterns of variation among communities, species, and individual organisms across environmental contexts, and I disentangle the direct effects of global change from the …

Conservation Planning In A Changing World, Austin Walker Milt

Doctoral Dissertations

As a science and practice dedicated to preventing, stopping, and reversing negative effects on nature, conservation is constantly faced with new challenges. Combine this fact with the rise of large, freely available datasets and computational power, and the result is a need to advance the methods and conceptual approach to conservation planning. In my dissertation I present novel methods and address research questions that aim to keep conservation science and practice relevant and effective in a changing world. This picture of continual change is illustrated in Chapter 1, in which I explore how the ongoing collection of observations of rare …

Evolution And Phylogeny Of The Parasitoid Subfamily Phasiinae (Diptera: Tachinidae), Jeremy Daniel Blaschke

Doctoral Dissertations

The first molecular phylogenetic analysis of the agriculturally important parasitoid subfamily Phasiinae (Diptera: Tachinidae) is presented, estimated from 128 worldwide taxa (80 genera) and approximately 7.6 kilobases of nuclear data. Special emphasis is placed on taxa with controversial taxonomic placement. The resultant phylogenetic tree is used to reconstruct ancestral character states, trace the evolution of significant adaptive traits within the Tachinidae, and test hypotheses about the classification of Phasiinae. Subfamily placements of the taxa Eutherini, Epigrimyiini, Litophasia, Strongygastrini, and Parerigonini are confidently resolved, the former three within Dexiinae and the latter two within Phasiinae. Due to sparse molecular evidence, …

Adaptive Radiation Along A Benthic/Pelagic Ecological Axis In North America’S Most Diverse, Endemic Clade Of Freshwater Fishes, Phillip Ray Hollingsworth Jr.

Doctoral Dissertations

Eastern North America is unparalleled throughout the temperate world in terms of freshwater fish biodiversity. A monophyletic group of approximately 250 cyprinid fishes, known as the open posterior myodome (OPM) clade, dominates the fish species richness in the freshwater ecosystems of this region. In this dissertation, I explore the influence of eco-evolutionary divergence along a benthic/pelagic habitat axis on the generation of this hyper-diverse group of fishes. My three chapters work synergistically to address the question: Did a historical shift from benthic to pelagic habitats by OPM cyprinids represent the invasion of an open adaptive zone and result in the …

Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble

Doctoral Dissertations

This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of …

A Novel Approach To Assess Environmental Changes In Marine Ecosystems Via Spectroscopic Analyses Of Microalgae, Rebecca Burke Horton

Doctoral Dissertations

Chemical analyses for environmental monitoring encounter many challenges which are imposed by a multitude of chemically complex and interrelated processes. For such investigations, innovative analytical methodologies must be developed which characterize chemical shifts of key environmental parameters in order to deduce insights into their ecological relevance. This dissertation is driven by an analytical chemistry perspective to develop chemical sensing techniques with the ultimate goal of gaining a deeper understanding of environmental changes and their chemical origins.

In order to overcome limitations inherent to any chemical sensor designed for a specific task, new paths are pursued which are based on the …

Diversity And Activity Of Roseobacters And Roseophage, Charles Ryan Budinoff

Doctoral Dissertations

Bacteria of the Roseobacter lineage are dominant bacterioplankton in coastal systems and contribute significantly to secondary production in oceanic environments. Generalities of Roseobacter ecology, diversity, and distributions are known, but the intraspecific differences between species and their dynamics over short temporal periods is not well understood. Bacteriophage that infect Roseobacters (‘roseophage’) have the potential to shunt secondary production into the dissolved carbon pool and through the process of infection alter Roseobacter physiology. Despite their significance, little effort was made prior to the onset of this study to characterize roseophage. Using culture dependent and independent approaches, I describe the diversity and …

Patterns Of Ecological Performance And Aquatic Insect Diversity In High Quality Protected Area Networks, Jason Lesley Robinson

Doctoral Dissertations

Protected areas are at the heart of plans for biodiversity conservation. Networks of protected areas may provide opportunities to protect conservation targets or objectives not attainable for single parcels of land. The landscape of potential decisions available to conservation planners is constrained by uncertainty about the form of future climate states. New methods are available that can provide objective assessments of the direction and magnitude of shifts in climate regimes that are not first filtered through theoretical responses of biodiversity. Successful predictions of where, in protected area networks, climates are most likely to change, or most likely to remain in …