Life Sciences Commons^™

Habitat Fragmentation And Range Margin Effects On Dispersal And Interactions Between Competitors, Rachel Roxann Harman

LSU Doctoral Dissertations

Dispersal is a fundamental process that affects local and regional dynamics, including population persistence, range expansion, and interspecific interactions, particularly as disturbance through habitat fragmentation and climate change. Here, my main objective was to ascertain how fragmentation affects dispersal and the interactions of competitors within the local patch and regional landscape. In my second chapter, I assessed dispersal through a literature review and population persistence model to examine the breadth and frequency of different density-emigration forms that occur in nature, including forms that are not prevalent in the literature. I conclude that these rare forms have important population dynamic consequences …

Natural Variation And Evolutionary Responses To Climate Change Stressors In Marine Invertebrates, Joanna Sarah Griffiths

LSU Doctoral Dissertations

Our rapidly changing climate is putting many species at risk of extinction and there is an urgent need to understand how species will respond to these changes. In this dissertation, I evaluate how three species of marine invertebrates (corals, oysters, and copepods) respond to stressful conditions in their current environments and how plasticity and evolutionary adaptation could alter their response to future climate change stressors. I first employed a space for time study to elucidate population differences in the response of cold-water corals, Balanophyllia elegans, to future ocean acidification. I found evidence that upwelling history (natural low pH exposure) influences …

Quantifying Impacts Of Climate Change On Species Interactions While Fostering Undergraduate Research Experiences Using The Monarch (Danaus Plexippus)- Milkweed (Asclepias Sp.) System, Matthew J. Faldyn

LSU Doctoral Dissertations

Species interactions, specifically plant-insect interactions, are ubiquitous worldwide. Climate change will alter species interactions by affecting abiotic conditions, affecting species phenologies, interaction strengths, and physiological development. However, climate change impacts are often studied using individual species, with limited consideration quantifying the direct and indirect impacts of climate change species interactions. Using lab, field, and greenhouse experiments, I investigated how climate change will directly and indirectly affect species interactions while also fostering undergraduate research experiences using the monarch butterfly (Danaus plexippus)- milkweed (Asclepias sp.) system.

In North America, a widely planted, invasive milkweed species, Asclepias curassavica, negatively …

Composition And Ecology Of Avian Communities Along Elevational Gradients In Borneo, Ryan Christian Burner

LSU Doctoral Dissertations

A primary goal of ecology is to explain the diversity and distribution of organisms. Species distributions can be a function of abiotic factors, species interactions, dispersal limitations, and history, but the relative importance of these factors is widely debated. Elevational gradients are useful systems for studying these effects because many of these factors vary predictably with elevation, and because elevational gradients are replicated many times across the earth. However, few quantitative surveys of Southeast Asian bird communities have been conducted along elevational gradients. In this study, I surveyed birds using point counts and measured habitat and temperature across primary forest …