Graduation Year

2025

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Geosciences

Major Professor

Ping Wang, Ph.D.

Committee Member

Robbin Trindell, Ph.D.

Committee Member

Joni Firat, Ph.D.

Keywords

beach nourishment, equilibration, green sea turtle, hatching success, loggerhead sea turtle, nesting success

Abstract

This study examines the influences of different beach nourishment designs and subsequent post-nourishment profile adjustments on loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles nest survival and reproductive success. Data on time-series post-nourishment beach-profile changes, positions and elevations of turtle tracks and nest/false-crawl apices, and sea turtle nest hatch/emergence success were collected on five high density nesting beaches along the east coast of Florida: Melbourne Beach, Jensen Beach, Jupiter Island Beach, Juno Beach, and South Hutchinson Island Beach. The field data collection was conducted in 2018, 2019, 2021, and 2022 with the main goal of documenting and comparing turtle nesting during the first and second years after nourishment. All the beaches except Jupiter Island Beach, which followed a traditional design with a flat back beach and steep foreshore, were nourished with a slope break, also known as a turtle-friendly nourishment design, although with varying morphological characteristics.Three beach morphological zones are distinguished for turtle nesting, active berm, storm berm, and dune field. Overall, 65.9% of loggerhead sea turtles laid their nests in the active berm, with 23.2% in the storm berm, and 10.8% in the dune field. For green turtles, 40% of the nests were in the dune, 36.1% in the active berm, and 23.9% in the storm berm. A nourishment design with a lower slope break elevation can lead to active berm growth during the nesting season. Completing construction a few months before the nesting season would allow essential profile equilibration. The design elevations of back beach and slope break had a significant influence on flooding potential of the egg chambers in the active berm, with lower design elevations having higher flooding potential. Due to the deeper egg chamber, green sea turtle nests in the active berm have a higher flooding risk than loggerhead sea turtle nests. Substantial spatial and temporal variations were measured, and no apparent trend in nesting and hatching success.

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