[Eoas-seminar] Reminder: Oceanography Dissertation Defense - Matthew Ware - 29th March CSL 1003 12pm
eoas-seminar at lists.fsu.edu
eoas-seminar at lists.fsu.edu
Fri Mar 29 09:31:24 EDT 2019
Ph.D. Biological Oceanography Candidate
Title: The effects of beach and species management actions on the nesting and incubation environment of sea turtles in the northern Gulf of Mexico
Major Professor: Dr. Mariana Fuentes
Defense Date: Friday, March 29
Location: CSL 1003 (Chemistry Auditorium)
Abstract: Sandy beaches are unique environments which offer billions of dollars-worth of ecosystem services. Management of sandy beaches tends to be anthropocentric - adjusting the coastal environment to suit the needs of human development and use. However, management actions can have important consequences for the natural functioning of these systems. Sea turtles offer an excellent case study in this balance. Understanding how the nesting and incubation environment may change under different beach- or species management actions is critical to ensuring their appropriate use in sea turtle population recovery. This dissertation investigated how two management actions affect the nesting and reproductive output of sea turtles: 1) sea turtle nest relocation including the assessment of inundation risk and 2) Leave No Trace ordinances. Though nest relocation is a common approach used to reduce losses due to inundation and other terrestrial threats, there are concerns that this strategy may alter the incubating environment of the developing embryos. In Alabama, the incubating environment between original-relocated site pairs were comparable, though relocation offered a minimal net benefit as it decreased emergence success and did not reduce the likelihood of inundation. More nests were being move than were necessary indicating additional information was needed to identify high-risk nesting sites. To better identify nests at-risk of wave exposure, a wave runup model was developed using historical beach elevation, offshore wave, and tide data. Wave runup modeling proved effective at identifying washed over nesting sites (83%). An updated digital elevation model (DEM) was not necessary as a time-averaged DEM performed better than, or comparable to, those using the most recent LiDAR survey. However, a more complete understanding of sea turtle embryonic tolerance to inundation would improve high-risk site identification. HOBO U20L-04 water level loggers were tested in situ to evaluate their potential to provide this inundation tolerance information versus existing PVC-based equipment. The HOBO loggers provided high resolution observations of inundation frequency, duration, and severity; however, their high cost will limit the scale of their deployment. Sea turtle population recovery is predicated not just on our ability to reduce losses of developing embryos, but on the continued availability of suitable nesting habitat itself. Leave No Trace ordinances are increasingly being used to combat the issue of marine debris including abandoned beach equipment. The ordinances had mixed success - though obstructed crawls did decline after the ordinance in Gulf Shores and Orange Beach, the presence of an obstruction did not influence a turtle's decision to nest and nesting success declined after the ordinance across the study area due to natural variation. These two management actions appeared to have only small effects on sea turtle hatchling production and population growth rates in the northern Gulf of Mexico. But as charismatic megafauna and valuable ecosystem service providers, their continued conservation based on the provision of suitable environmental conditions serves as an important example of the need to balance anthropocentric coastal zone management with ecosystem function.
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