Graduation Year
2024
Document Type
Thesis
Degree
M.S.
Degree Name
Master of Science (M.S.)
Degree Granting Department
Marine Science
Major Professor
Christopher D. Stallings, Ph.D.
Committee Member
Ernst B. Peebles, Ph.D.
Committee Member
Meagan N. Schrandt, Ph.D.
Keywords
climate change, ecological drift, Gulf of Mexico, submerged aquatic vegetation, tropicalization
Abstract
Subtropical estuaries often support abundant and diverse faunal assemblages, but it is unclear how these productive ecosystems are responding to climate change. In the eastern Gulf of Mexico, estuarine faunal assemblages have been sampled for decades as part of a fisheries-independent long-term monitoring program. I assessed trends in submerged aquatic vegetation, water temperature, and the abundance, richness, and structure of faunal assemblages over more than two decades in four estuarine systems using this dataset. I used both univariate and multivariate analyses to quantify and describe the dynamics of these habitat and faunal variables. Further, I separated my analyses for summer and winter seasons since the latter has been observed to experience stronger responses to climate change in other systems. Submerged aquatic vegetation was generally stable, although I observed both decreasing and increasing cover in different systems. In contrast, water temperature increased in all systems during summer and winter. The rate of water temperature increase in winter was more than three times greater than in summer. Although faunal abundance and richness was generally stable over time, most systems exhibited slow, but significant, changes in assemblage structure consistent with ecological drift. Further, some faunal changes were indicative of tropicalization, where nearly 30% of the species that increased in abundance had distributions centered at lower latitudes. Moreover, there was a reduction in abundance of a temperate-centered taxon across all study systems in the winter. These results reflected a combination of both stability and change in habitat and the faunal assemblages it supports over the past two decades. These ecosystems should continue to be monitored in the face of chronic and acute disturbances of climate change that have the potential to induce profound ecological shifts.
Scholar Commons Citation
Miller, Garrett L., "Subtropical Estuarine Ecosystems Display Both Long-term Stability and Change" (2024). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/10539
