Digital Commons Network^™

Taking Apart The Time Machine: Investigating Space-For-Time Substitution Modeling In The Florida Everglades, Theresa Kelly Brown

FIU Electronic Theses and Dissertations

Space-for-Time substitution modeling has been used with increasing frequency to identify functional relationships between environmental drivers and ecological responses. I investigated the use of space-for-time substitution as a null model and beta diversity as a validity test for this null model in the Greater Everglades aquatic metacommunity. I began by conducting a literature review and analysis to investigate the suitability of the space-for-time substitution method as a null model. I then analyzed beta diversity of the Greater Everglades aquatic metacommunity through a sums-of-squares approach. Finally, I tested for correlation between the beta diversity analysis and the space-for-time models. Results indicate …

Incorporating Early Life History And Recruitment In Analysis Of Population Dynamics Of Wetland Fishes, John Vincent Gatto

FIU Electronic Theses and Dissertations

Hydrological variation is believed to be the major abiotic factor influencing fish recruitment in floodplain ecosystems. However, past studies fail to address the impact of hydrology on the three major drivers of recruitment: age-specific growth and mortality, and dispersal. I examined long-term recruitment dynamics for six fish species inhabiting the Everglades by addressing the impact of hydrology on these important characteristics. I then linked these changes to annual fluctuations in population size.

Before interpreting time-series data on recruitment, I evaluated the impact of size-selective bias from sampling gear on our interpretation of hydrological drivers of recruitment. Analyses revealed that individuals …

Mechanisms For The Persistence Of The Coral Holobiont In The Warming Oceans Of The Anthropocene, Daniel G. Merselis

FIU Electronic Theses and Dissertations

Coral Reefs are rapidly deteriorating in response to an onslaught of human-mediated stressors. Just one stressor alone, climate change, may extirpate coral reef ecosystems within a human lifetime, threatening societal and ecological catastrophe. Reef-derived ecosystem services are crucial for sustenance, coastal protection, and economic prosperity in over 100 countries. Near-term human decisions will determine whether reef-corals, the ecosystems they engineer, the 25% of marine biodiversity they support, and the human communities that depend upon them can be protected. My dissertation aims to characterize the potential for corals' adaptive mechanisms to facilitate their continued survival- information which will only represent hope …

Effects Of Phosphorus On Benthic Diatom Assemblage Network Structure, Eric M. Massa

FIU Electronic Theses and Dissertations

Ecological network analysis helps identify how relationships among species differ over time and across sets of species. Microbial assemblages are ideal for evaluating changes in species interactions due to environmental changes because they are speciose and respond at multiple scales. To determine how phosphorus limitation influences diatom network structure, I analyzed relationships among 257 species of diatoms from benthic microbial (periphyton) mats from 10 years of annual samples from 136 sites. Expected evidence of changes in network structure in response to periphyton TP were not found, likely due to species replacement with increased TP. Analysis of species connection distributions and …

Cavity Nest Webs As A Template For Studying Non-Trophic Interactions In Invasion Ecology, Joshua M. Diamond

FIU Electronic Theses and Dissertations

Invasive exotic animals are considered destructive forces in cities for preying on and competing with native species. I examined an aspect of competition from a different perspective, focusing on the role of Miami’s rich exotic bird assemblage in its cavity nest web, where a supply of woodpecker-created cavity nests limited by urbanization is the focal point of competition. We located 967 nest trees with 1,864 cavities and determined that woodpeckers successfully nested in this tropical urban region by exploiting standing dead palms (snags). Native upland forests were the most important cover type for woodpeckers but planted landscapes like parks and …

Evolutionary Expansions And Neofunctionalization Of Ionotropic Glutamate Receptors In Cnidaria, Ellen G. Dow

FIU Electronic Theses and Dissertations

Reef ecosystems are composed of a variety of organisms, transient species of fish and invertebrates, microscopic bacteria and viruses, and structural organisms that build the living foundation, coral. Sessile cnidarians, corals and anemones, interpret dynamic environments of organisms and abiotic factors through a molecular interface. Recognition of foreign molecules occurs through innate immunity via receptors identifying conserved molecular patterns. Similarly, chemosensory receptors monitor the environment through specific ligands. Chemosensory receptors include ionotropic glutamate receptors (iGluRs), transmembrane ion channels involved in chemical sensing and neural signal transduction. Recently, an iGluR homolog was implicated in cnidarian immunological resistance to recurrent infections of …

Computational Analysis Of Large-Scale Trends And Dynamics In Eukaryotic Protein Family Evolution, Joseph Boehm Ahrens

FIU Electronic Theses and Dissertations

The myriad protein-coding genes found in present-day eukaryotes arose from a combination of speciation and gene duplication events, spanning more than one billion years of evolution. Notably, as these proteins evolved, the individual residues at each site in their amino acid sequences were replaced at markedly different rates. The relationship between protein structure, protein function, and site-specific rates of amino acid replacement is a topic of ongoing research. Additionally, there is much interest in the different evolutionary constraints imposed on sequences related by speciation (orthologs) versus sequences related by gene duplication (paralogs). A principal aim of this dissertation is to …