Physical Sciences and Mathematics Commons^™

Not Too Hot, Not Too Cold, But Moderately Variable: The Influence Of Environmental Variability On Coral Thermal Tolerance, Courtney Nicole Klepac

Biological Sciences Theses & Dissertations

Anthropogenic climate change is causing an increase in the frequency and severity of marine heat waves, resulting in declining health of coral reef ecosystems worldwide. Coral bleaching events – the breakdown in symbiosis between the coral host and their intracellular photosynthetic algae – are increasingly common in recent years and contribute to widespread losses in coral cover. However, bleaching and heat stress responses vary across spatial scales both within and among coral species. Coral populations native to highly variable environments can have greater bleaching resistance than corals from more stable habitats and corals transplanted into these variable reef sites can …

Investigating The Effects Of Sea-Level Rise And Increasing Salinity On Procambarus Lunzi Of Sapelo Island, Georgia, Samuel Long

Biology Theses

Barrier islands have great ecological and economical importance and face a threat from increasing sea-level due to climate change. Erosion of existing freshwater lens and ocean inundation could greatly change freshwater availability on the island. This could have significant impacts on freshwater crayfish like Procambarus lunzi, which are complexly intertwined into the trophic food web of the island. This study’s goal was to investigate the salinity tolerance of this crayfish on Sapelo Island, Georgia, in an attempt to predict the possible effects and response to sea-level rise by this crayfish. Crayfish were wild-caught from the island in March, June, and …

Sea Level Rise Vulnerability Analysis Of Mangrove Ecosystems Using Gis, Kayla Caldwell

HCNSO Student Theses and Dissertations

Climate change is accelerating beyond what is natural due to excessive emissions from human activities. The sea level has been rising for many years and is currently at a rate of 3.6 mm/yr. Mangroves are known to only keep pace with a sea level rate of less than 1.2 mm/yr. Mangroves are particularly vulnerable to rising sea levels if they are not able to keep pace through vertical sediment accretion or inland migration. To test the vulnerability of the south Florida mangrove ecosystems to sea level rise, this study analyzed changes in the mangrove forest coverage of the Oleta River …

Local Adaptation Constrains Drought Tolerance In A Tropical Foundation Tree, Kasey E. Barton, Casey Jones, Kyle F. Edwards, Aaron B. Shiels, Tiffany Knight

United States Department of Agriculture Wildlife Services: Staff Publications

1. Plant species with broad climatic ranges might be more vulnerable to climate change than previously appreciated due to intraspecific variation in climatic stress tolerance. In tropical forests, drought is increasingly frequent and severe, causing widespread declines and altering community dynamics. Yet, little is known about whether foundation tropical trees vary in drought tolerance throughout their distributions, and how intraspecific variation in drought tolerance might contribute to their vulnerability to climate changE.
2. We tested for local adaptation in seedling emergence and establishment with a full-factorial reciprocal transplant experiment including 27 populations and 109,350 seeds along a 3,500 mm precipitation gradient for …

Assessing The Hierarchy Of Long-Term Environmental Controls On Diatom Communities Of Yellowstone National Park Using Lacustrine Sediment Records, Victoria Chraibi, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

An ecosystem’s ability to maintain structure and function following disturbance, defined as resilience, is influenced by a hierarchy of environmental controls, including climate, surface cover, and ecological relationships that shape biological community composition and productivity. This study examined lacustrine sediment records of naturally fishless lakes in Yellowstone National Park to reconstruct the response of aquatic communities to climate and trophic cascades from fish stocking. Sediment records of diatom algae did not exhibit a distinct response to fish stocking in terms of assemblage or algal productivity. Instead, 3 of 4 lakes underwent a shift to dominance by benthic diatom species from …

Patterns And Potential Causes Of Changing Winter Bird Distributions In South Dakota, David L. Swanson, Reza Goljani Amirkhiz, Mark D. Dixon

The Prairie Naturalist

Average winter temperatures in the north-central United States have been increasing since the 1970s, and this warming might influence winter distributions of birds in the region. Species potentially influenced by such winter warming include short-distance migrants for which the northern boundary of the winter range is influenced by temperature, such as hermit thrush (Catharus guttatus), yellow-rumped warbler (Setophaga coronata), and fox sparrow (Passerella iliaca). We examined winter records during 1974–2017 from a citizen-science bird observation database for South Dakota to determine recent trends in winter records for these three species. We compared their occurrence patterns with those for three benchmark …

Gulf Coast Marine Laboratories Past, Present And Future, Donald F. Boesch

Gulf and Caribbean Research

I spent my nearly 50—year career in marine science working at marine laboratories, most of that as a chief executive officer. So, it is appropriate that my reflections are about marine laboratories, rather than my own science. After relating my career course, I turn my attention to the history and development of marine laboratories along the U.S. coast of the Gulf of Mexico (GOM). Surprisingly, the region’s first laboratory was actually constructed in 1903 at Cameron, LA, but operated less than a decade before closing. It was not until after World War II that the university—affiliated marine laboratories of today …

Higher Temperatures Have Contrasting Effects On Different Components Of Forage Quality For Caribou In Northern Alaska, Heidi Becker

Electronic Theses and Dissertations

Rising temperatures in the Arctic may affect vegetation, which in turn can affect herbivores, such as caribou, that rely on these plants for forage. Several plant traits contribute to forage quality, including digestibility, nitrogen content, and antiherbivory secondary compounds, but the effect of temperature on these traits individually and combined is unclear. I conducted a three-component study on the effect of higher temperatures on the forage quality of graminoids, deciduous shrubs, and evergreen dwarf shrubs on the North Slope of Alaska. The components included: 1) short and long-term experimental warming, 2) natural temperature variation between south and north-facing slopes, and …