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 …

The Spatial Distribution Of Invasive Plant Presence, Abundance, And Impact, Evelyn M. Beaury

Doctoral Dissertations

Across the globe, native ecosystems are increasingly threatened by the spread and negative impacts of non-native, invasive plants. While many hypotheses explore what contributes to the damage caused by invasive species, few studies have tested these hypotheses at the macroscale. My dissertation addresses this knowledge gap by synthesizing thousands of vegetation surveys from ecosystems across the United States. I leverage existing, as well as explore new macroecological methods to deepen our understanding of the spatial ecology of plant invasions. My dissertation also asks how effective management and policy has been at reducing plant invasions. The primary introduction pathway for invasive …

Ecology And Conservation Of Grey Crowned Cranes (Balearica Regulorum) In Tanzania, Bridget Amulike

Doctoral Dissertations

Grey-crowned cranes (Balearica regulorum) are listed as endangered and their population throughout Africa has declined by 50% from the period of 1985–2004. The major causes for their population loss are mainly linked to habitat loss and the illegal capture of live birds and collection of their eggs and other parts. Currently, throughout Africa, little has been done to study and protect grey crowned cranes. In this study, I incorporated local people’s knowledge, using survey questionnaires to investigate the distribution of grey crowned cranes in Arusha, Kilimanjaro, Singida, and Mbeya Region in Tanzania. I also investigated the perception and attitudes …

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 …

Attitudes And Interactions Of Indigenous And Non-Indigenous People With Wildlife In The Northern Talamanca Mountains Of Costa Rica, Carolina Saenz-Bolaños

Doctoral Dissertations

In this study I investigated wildlife and human use of landscapes in the northern Talamanca Mountains of Costa Rica (Pacuare-Barbilla sector), including three contiguous protected areas (a national park, a forest reserve, and an indigenous territory), as well as surrounding unprotected areas. I describe and compare perceptions of wildlife by different social actors in the Pacuare-Barbilla sector, collecting information with a questionnaire as an instrument. I also inventoried and monitored the abundance and distribution of a variety of wildlife species occurring throughout the area using camera traps. The species with greater abundance or only occurrence in the national park were …

Monitoring Mammals At Multiple Scales: Case Studies From Carnivore Communities, Kadambari Devarajan

Doctoral Dissertations

Carnivores are distributed widely and threatened by habitat loss, poaching, climate change, and disease. They are considered integral to ecosystem function through their direct and indirect interactions with species at different trophic levels. Given the importance of carnivores, it is of high conservation priority to understand the processes driving carnivore assemblages in different systems. It is thus essential to determine the abiotic and biotic drivers of carnivore community composition at different spatial scales and address the following questions: (i) What factors influence carnivore community composition and diversity? (ii) How do the factors influencing carnivore communities vary across spatial and temporal …

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 …

Improving Understanding Of Forest Communities And Biodiversity With Multi-Dimensional Landscape Gradients, Ben J. Padilla

Doctoral Dissertations

This dissertation was motivated by a desire to understand the effects of habitat degradation and urbanization on a single species in a single study system in western Massachusetts, the red-backed salamander (Plethodon cinereus), but along the way unexpected conceptual and methodological hurdles caused the work to grow into a multi-species, multi-region, and multi-scale endeavor. As I designed my dissertation research and began considering approaches to quantifying heterogeneity and human influence in my study landscape, I recognized inconsistencies in methods used to define and quantify landscape metrics, particularly in urban systems. To investigate further, I conducted a critical review …

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 …

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …

Neogene History Of The Kuroshio Current Extension And Planktic Foraminifera Evolutionary Implications, Adriane Lam

Doctoral Dissertations

There are outstanding questions as to how important currents are to dispersal, especially for the evolution of planktic foraminifera. During the Neogene Period there were significant increases in the diversity of planktic foraminifera that occurred during major tectonic gateway closures, episodes of warming and cooling, and reorganization and development of ocean gyres and currents. Relatedly, the behavior of some currents, namely western boundary currents, remains unknown through these times of global tectonic and climate events. This dissertation addresses outstanding questions related to how the Kuroshio Current Extension, the western boundary current of the northwest Pacific, responded to major tectonic and …

Drivers And Consequences Of Carbon Use Efficiency - And Its Measurement In Soil, Grace Pold

Doctoral Dissertations

Soils serve as massive carbon sinks, but their ability to continue this ecological service is contingent on how the resident soil microbial community will respond to the ongoing climate crisis. One key dimension of the microbial response to warming is its carbon use efficiency (CUE), or the fraction of carbon taken up by an organism which is allocated to growth rather than respiration. However, the scientific community is still in the early stages of understanding the drivers, consequences - and even accurate measurements of - CUE. In this dissertation, I first quantified the variability of CUE and its responsiveness to …

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 …

The Role Of Phenotypic Integration In Mammalian Tooth Function And Jaw Morphological Diversity, Andrew Conith

Doctoral Dissertations

Here I investigate how two major components of the mammalian feeding system, teeth and jaws, are influenced by functional, environment, and developmental factors. First, I build physical models of the molars from two early mammals, Morganucodon and Kuehneotherium, and compare their ability to process a proxy food item. Early mammals were under strong selection to reduce metabolic costs, so any savings in energy during feeding would be advantageous. I tested the ability of both mammals to process a hard and soft food item with material properties similar to that of the insects they would have likely consumed. Morganucodon was …

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 …

Improving Conservation Efforts Through A Better Understanding Of Forest Elephant Ecology, The Impacts Of Threats On Elephants And Freshwater Fisheries In Northern Congo, Roger Patrick Boundja

Doctoral Dissertations

IMPROVING CONSERVATION EFFORTS THROUGH A BETTER UNDERSTANDING OF FOREST ELEPHANT ECOLOGY, THE IMPACTS OF THREATS ON ELEPHANTS AND FRESHWATER FISHERIES IN NORTHERN SEPTEMBER 2016 ROGER PATRICK BOUNDJA, B.Sc. FORESTRY, MARIEN NGOUABI UNIVERSITY, BRAZZAVILLE MSc. UNIVERSITY OF CAPE TOWN PhD. UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Curtice R. Griffin Catch data, including fish numbers, length-weight were collected during a multi-mesh Gillnet fisheries-independent survey in 2007-2008, and fisheries-dependent mixed gear surveys in 2009-2010 and 2015 across 400km stretch of the Sangha River located in the Sangha Tri-National. Overall, very high species richness (Chao 2 mean=250, SD=16.15) and diversity index (Simpson Inverse …

Expansion Of And Reclassification Within The Family Lachnospiraceae, Kelly N. Haas

Doctoral Dissertations

Many of the taxa in the family Lachnospiraceae are currently misclassified as Clostridium spp. Here attempt to rectify many of these issues, beginning with an in-depth genomic and physiologic analysis of Clostridium methoxybenzovorans, culminating in the assertion that is a heterotype of Clostridium indolis, followed by reclassification of the broader group in which this organism resides. We propose two novel genera, Lacriformis and Enterocloster, to reclassify this clade, this includes reclassification of Clostridium sphenoides, Clostridium indolis, Clostridium saccharolyticum, Clostridium celerecrescens, Clostridium xylanolyticum, Clostridium algidixylanolyticum, Clostridium aerotolerans, Clostridium amygdalinum, and …

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 …

The Effectiveness And Applicability Of Amphibians As Indicator Species For Long-Term Monitoring Of Ecological Changes In New England Forests, Ahmed Siddig

Doctoral Dissertations

The objective of this study is to assess the potential of two amphibians species, Eastern Red-backed Salamander (Plethodon cinereus (Green)) and Eastern Red-spotted Newt (Notopthalmus viridescens viridescens Rafinesque), as indicator species of forest disturbances at Harvard Forest, located in Petersham, Massachusetts, United States. Specifically, I 1) assess the impacts of these focal species to decline of hemlock forests in Harvard Forest; 2) calibrate abundance indices of P. cinereus based on artificial and natural objects surveys with a population size estimator based on depletion sampling; and 3) assess the potential of these salamanders as indicator species by developing an …

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, …

Movements And Conservation Of The Migratory White-Eared Kob (Kobus Kob Leucotis) In South Sudan, Malik D. Marjan

Doctoral Dissertations

The annual movements of white-eared kob (Kobus kob leucotis), tiang (Damaliscus korrigum tiang), in eastern South Sudan was investigated to provided appropriate information for developing effective conservation actions for the migratory kob. Although kob is the focus of the study tiang has been included as the two migrations are ecologically linked and overlap at least in the wet season. During the 20 years of the civil war which ravaged South Sudan, the kob and tiang populations were thought to be severely hunted for food by both the combatants and local people to the extent that their …

Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo

Doctoral Dissertations

Assessment and management of ecosystem services demands diverse knowledge of the system components. Land use change occurring mainly through deforestation, expansion of agriculture and unregulated extraction of natural resources are the greatest challenges of the Congo basin and yet is central to supporting over 100 million people. This study undertook to implement an integrated modeling of multiscale ecosystems of central African watersheds and model the impact of anthropogenic factors on elephant population in Greater Virunga landscape. The study was conducted at varied scales, regional, landscape, and community. Regional study included watershed analysis and hydrological assessment using remotely sensed data implemented …