Life Sciences Commons^™

Assessing The Functional Similarity Of Native And Invasive Anolis Lizards In The Food Webs Of Structurally-Simple Habitats In Florida, Nathan W. Turnbough

Doctoral Dissertations

Invasive species often displace ecologically-similar native species, but the extent to which invading and displaced species function similarly in the food web processes of invaded communities is largely unknown. I investigated whether populations and individuals of an invasive Anolis lizard (the brown anole, Anolis sagrei) and the native congener it displaces in Florida (the green anole, Anolis carolinensis) are functionally equivalent in the food webs of open and structurally-simple habitats. In a system of invaded and uninvaded dredge-spoils islands, I found that both arthropod communities and winter bird communities covaried with brown anole abundance (and therefore the identity …

Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li

Doctoral Dissertations

Photosystem I (PSI) forms trimeric complexes in most characterized cyanobacteria. We had reported the tetrameric form of PSI in the unicellular cyanobacterium, Chroococcidiopsis sp. TS-821 (TS-821). Using Cryo-EM, a 3D model of the PSI tetramer structure at 11.5 [Angstrom] resolution was obtained and a 2D map within the membrane plane of at 6.1 [Angstrom]. In contrast to the three-fold symmetry in trimeric PSI crystal structure from T. elongatus, two different inter-monomer interactions involving PsaLs are found in the PSI tetramer. Phylogenetic analysis based on PsaL protein sequences shows that TS-821 is closely related to heterocyst-forming cyanobacteria. Additionally, this tetrameric …

On The Quantification Of Complexity And Diversity From Phenotypes To Ecosystems, Zachary Harrison Marion

Doctoral Dissertations

A cornerstone of ecology and evolution is comparing and explaining the complexity of natural systems, be they genomes, phenotypes, communities, or entire ecosystems. These comparisons and explanations then beget questions about how complexity should be quantified in theory and estimated in practice. Here I embrace diversity partitioning using Hill or effective numbers to move the empirical side of the field regarding the quantification of biological complexity.

First, at the level of phenotypes, I show that traditional multivariate analyses ignore individual complexity and provide relatively abstract representations of variation among individuals. I then suggest using well-known diversity indices from community ecology …

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 …

Distribution And Population Dynamics Of Ungulates In The Mongolian Gobi, Buuveibaatar Bayarbaatar

Doctoral Dissertations

The Mongolian Gobi is one of the most spectacular and important regions in Central Asia, comprising the largest area of intact grassland in the world. In recent years, a growing human population, expanding exploitation of natural resources, and the development of infrastructure in the region place increasing pressure on these species and their habitats. This dissertation has focused on three species of ungulates such as Mongolian saiga (Saiga tatarica mongolica) in western Mongolia, and Asiatic wild ass (Equus hemionus), and goitered gazelle (Gazella subgutturosa) in Southern Gobi. The study on endangered saiga antelope in …

Evaluating Resistance Surfaces For Modeling Wildlife Movement And Connectivity, Katherine Zeller

Doctoral Dissertations

The continued growth of human populations and associated development in many areas of the world is causing persistent fragmentation of natural habitats. In response, wildlife corridors are often promoted as essential for the conservation of wildlife species. Wildlife corridors allow for the movement of individuals between habitat patches and confer many benefits including the maintenance of metapopulations and metapopulation dynamics, the maintenance of seasonal migratory routes, genetic exchange, and the potential for individuals and populations to shift their ranges in response to climate change. Wildlife corridors are modeled across a resistance-to-movement surface where resistance represents the willingness of an organism …

Evaluating Digital Vhf Technology To Monitor Shorebird And Seabird Use Of Offshore Wind Energy Areas In The Western North Atlantic, Pamela H. Loring

Doctoral Dissertations

Information on offshore movements of high priority bird species is needed for monitoring and managing adverse effects of offshore wind energy development in the western North Atlantic Ocean. This information is particularly important at night and during periods of inclement weather when risks of collision with offshore wind turbines may be elevated. For small-bodied avian taxa, technologies for monitoring movements of individually-marked birds are limited since satellite-based devices are still too heavy (> 5 g) for use on birds weighing < 150 g. In this dissertation, I evaluate the use of light-weight (1 to 1.5 g) digital VHF transmitters and a network of automated radio telemetry stations for tracking shorebirds and seabirds in offshore areas. In Chapter One, I compare digital VHF telemetry with satellite telemetry for tracking a shorebird, the American Oystercatcher (Haematopus palliatus), at nesting areas in coastal Massachusetts. In Chapter Two, I evaluate possible adverse effects and retention time …

The Meat-Farming Ants: Predatory Mutualism Between Melissotarsus Ants (Hymenoptera: Formicidae) And Armored Scale Insects (Hemiptera: Diaspididae), Scott A. Schneider

Doctoral Dissertations

Ant agricultural mutualisms are common, well studied, and receive attention from scientific and public spheres due to shared similarities with human agriculture (i.e. ant/fungus ‘crop farming’ and ant/insect ‘dairy farming’). They also serve as important model systems for studying many facets of mutualism. This study reveals that the repertoire of ant agriculture may also include ‘meat farming’. Predatory mutualisms occur between Melissotarsus ants and various species of armored scale insects. This dissertation employs a multi-disciplinary approach to investigate the evolutionary history and nature of ant/diaspidid mutualisms. Chapter 1 reviews the current state of knowledge regarding species composition of these associations …

Song Perception In Communication Networks, Sarah Goodwin

Doctoral Dissertations

Communication is a cornerstone of animal behavior and mediates myriad interactions pertaining to survival and reproduction. For animals that communicate acoustically, signals are carried to multiple receivers in what is described as communication networks. In my dissertation, I explore how songbirds and their songs are perceived and used in networks. First, I examine a dilemma many animals face when communicating in a network – how do animals contend with overlapping, conspecific noise? Using a playback experiment in the field, I document Black-capped Chickadees (Poecile atricapillus) shifting the frequency of their song in the presence of overlapping noise. Next, …

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 …

Plant-Microbe Interactions Influence Ecosystem Processes: The Role Of Roots And Mycorrhizal Fungal Hyphae On Terrestrial Carbon Dynamics, Jessica Andrea Moore

Doctoral Dissertations

Plant-microbe interactions shape ecosystem processes such as productivity and decomposition of organic matter. Plants interact with mycorrhizal fungal hyphae to acquire nutrients from soil in exchange for plant-assimilated carbon. The mycorrhizal interaction is therefore a key influence on ecosystem carbon dynamics. Mycorrhizal fungi are key players in soil carbon cycling as they stimulate plants to allocate carbon belowground, and mycorrhizal fungal hyphae interact with microbial decomposers of soil carbon. However, there are few studies on mycorrhizal fungal hyphal interactions with roots and soil organisms in light of soil carbon accrual and release, important ecosystem processes. In my doctoral research, I …

The Role Of Hearing In The Brown Anole (Anolis Sagrei, Polychrotidae): A Behavioral Perspective, Lisa Ragan Cantwell

Doctoral Dissertations

All animals are likely to encounter a predator during their lifetime. Prey can reduce their risk of predation by recognizing dangerous situations and modifying their behavior accordingly. Many animals are known to utilize auditory predator cues to assess risk. However, lizards have historically been assumed to emphasize vision to assess risk because most species do not vocalize and, therefore, do not themselves communicate using sound. I conducted a field experiment to investigate the ability of the brown anole (Anolis sagrei, Polychrotidae) to 1) use auditory cues to evaluate predation risk and 2) distinguish between threatening and non-threatening avian …

Computational Identification Of Terpene Synthase Genes And Their Evolutionary Analysis, Qidong Jia

Doctoral Dissertations

Terpenoids, the largest and most structurally and functionally diverse class of natural compounds on earth, are mostly synthesized by plants to be involved in various plant environment interactions. Some terpenoids are classified as primary metabolites essential for plant growth and development. Terpene synthases (TPSs), the key enzymes for terpenoid biosynthesis, are the major determinant of the tremendous diversity of terpenoid carbon skeletons. The TPS genes represent a mid-size family of about 30-100 functional genes in almost all major sequenced plant genomes. TPSs are also found in fungi and bacteria, but microbial TPS genes share low levels of sequence similarity and …

Biochemistry And Evolution Of The Phytohormone-Methylating Sabath Methyltransferase In Plants, Minta Chaiprasongsuk

Doctoral Dissertations

Known members of Phytohormone-methylating compounds are plant synthesis compounds that serve as attractants of other living organisms beneficial to the plants or as defense against other biotic as well as abiotic agents. To increase their fitness and survival in a stressful environment plants produce distinct sets of phytohormone-methylating compounds. Plant genomes can encode the necessary enzymes to acquire the ability to make new specialized compounds during evolution. This dissertation aims to investigate the biochemical and biological functions and evolution of SABATH genes in different lineages of plants. Black cottonwood, Brachypodium and Norway spruce genome were used as the model for …

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 …

Modeling Feral Hogs In Great Smoky Mountains National Park, Benjamin Anthony Levy

Doctoral Dissertations

Feral Hogs (Sus scrofa) are an invasive species that have occupied the Great Smoky Mountains National Park since the early 1900s. Recent studies have revitalized interest in the pest and have produced useful data. The Park has kept detailed records on mast abundance as well as every removal since 1980 including geographic location and disease sampling. Data obtained via Lidar includes both overstory as well as understory vegetation information. In this dissertation, three models were created and analyzed using the detailed data on vegetation, mast, and harvest history. The first model is discrete in time and space and …

Evolvability Of The Skull: A Study Of Genetic Basis And Integration In The Teleost Craniofacial Skeleton, Yinan Hu

Doctoral Dissertations

As the field of evolutionary biology pivots away from a gene-centric view of how adaptive evolution proceeds, renewed emphasis is placed on the origin of phenotypic variation. Understanding the developmental processes that underlie the production of novel traits, and how they might influence evolvability, is considered a primary goal in the on-going “extended evolutionary synthesis”. The following dissertation explores these questions in the context of adaptive radiations in fish, with a focus on morphological variation in the craniofacial skeleton. Specifically, the first chapter investigates the genetic and developmental basis of shape (co-)variation in the feeding apparatus of African cichlid fishes, …