Defense Date

4-20-2023

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

David Gilliam, Ph.D.

Second Advisor

Brian Walker, Ph.D.

Third Advisor

Abigail Renegar, Ph.D.

Keywords

Benthic community, Long-term coral reef monitoring, Coral reef disturbance, Tropical storms, Hurricanes, Temperature stress

Abstract

Acropora cervicornis is a species of stony coral that can exist in large thickets that provide functionally unique habitat. However, populations have declined by 98% in some areas of the Caribbean. Even in death, the structure from an A. cervicornis thicket provides surface area for the attachment of benthic organisms. Broward County Acropora (BCA) is an A. cervicornis thicket, located off Fort Lauderdale, Florida, which has been monitored since 2003. The objective of this study was to describe the temporal changes in community structure in response to 20 years of disturbances affecting BCA. Data was collected by taking images along four linear transects to assess temporal changes in percent benthic cover from 2003-2022. Acropora cervicornis cover declined from 34.8 ± 2% in 2003 to 2.4 ± 0.6% in 2022. The most severe declines observed were related to thermal stress, tropical storm and hurricane damage, disease, and predation in 2005-2006, 2010-2011, and 2015-2016. As A. cervicornis died, other taxa utilized the remaining dead structure, with increases in Agaricia agaricites, macroalgae, and crustose coralline algae cover observed. There was also evidence of structural decline toward the end of the study. Based on the detected trends, it is likely this long-term monitoring effort will capture the complete loss of this unique and complex habitat in the coming years. Thicket recovery will likely require active restoration and a reduction in local stressors. These remnant thickets are valuable research areas, as they provide opportunities to assess community dynamics, resilience, succession, and the response to disturbances.

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