Sea turtle tolerance to inundation, mapping wave exposure, and the use of nest relocation
Based on the Fort Morgan peninsula in southern Alabama, this project aims to provide 1) a better understanding of how well developing sea turtle embryos tolerate inundation, and 2) new tools for identifying which areas of the beach are most at-risk of inundation to better inform relocation decisions.
The peninsula hosts the highest density of loggerhead sea turtle (Caretta caretta) nesting in Alabama. This, coupled with the presence of 2 Gulf coast units of the Bon Secour National Wildlife Refuge, makes it an excellent site to study how long developing turtle embryos can “hold their breath”.
Nests laid close to the water which are at risk of inundation or erosion from high tides, tropical storms, or hurricanes are commonly relocated closer to the dune toe. This relocation can 1) result in the loss of developing embryos through the disruption of embryonic membranes, 2) increase the production of female hatchlings by changing the eggs’ incubating environment, and/or 3) increase predation from coyotes, foxes, raccoons, birds and other predators by moving the nest closer to their preferred hunting habitat and increasing the distance hatchlings must crawl to the water. There may also be sublethal effects such as reduced muscular development as a result of the altered incubation environment. Therefore, nest relocation should only be done as a last resort.
By improving our understanding of sea turtle embryonic tolerance to inundation and mapping where on the beach this threshold is exceeded, we can better target relocation decisions to only those nests which most need it.
This project was funded by the Alabama Department of Conservation and Natural Resources, the Winchester Scholarship, and Florida State University. Equipment toward this project has been donated by Onset Computer Corporation.
- The results of this work have been published in Ocean and Coastal Management (https://www.sciencedirect.com/science/article/pii/S0964569118310202),
Journal of Experimental Marine Biology and Ecology (https://www.sciencedirect.com/science/article/pii/S0022098118300121), and Chelonian Conservation and Biology (https://www.chelonianjournals.org/doi/abs/10.2744/CCB-1306.1),
as well as presented at the 37th and 39th International Sea Turtle Symposia and the Southeast Regional Sea Turtle Meeting. A map of wave exposures for the Alabama Gulf Coast, data, and R code is available on FigShare (https://figshare.com/projects/Using_wave_runup_modeling_to_inform_sea_turtle_nest_relocation/37958).
Influence of Leave No Trace-type ordinances on sea turtle nesting success
This project covered the entire Gulf Coast of mainland Alabama to determine if 1) nesting success improved, or 2) the frequency of obstructed crawls decreased following the enactment of Leave No Trace ordinances.
In 2015, the cities of Gulf Shores and Orange Beach, Alabama both enacted ordinances requiring beachgoers to remove personal equipment from the beach no later than 1 hour after sunset, among other restrictions.
However, the ordinances do not apply to unincorporated portions of Baldwin County, such as Fort Morgan. On the other hand, there are 2 unpopulated protected areas (the Bon Secour NWR and Gulf State Park) which have had their own versions of the Leave No Trace ordinance. This configuration, plus historical data available before the city ordinances were enacted, provides an ideal situation to evaluate how the Leave No Trace ordinances impact nesting success.
Tents, umbrellas, beach chairs, holes, trash, etc. can prevent an emerging female from reaching a suitable nesting location, restrict hatchlings from reaching the water, or cause injury or death to animals unfortunate enough to become entangled. For example, a Kemp’s Ridley sea turtle (Lepidochelys kempii) found on the Bon Secour NWR strangled by a beach chair on 14 July 2018 made international news, and has become a rallying cry for locals pushing for the expansion of the Leave No Trace ordinance (see related blog post about the incident).
- The results of this work were presented at the 39th Annual Symposium on Sea Turtle Biology and Conservation in Charleston, South Carolina, USA, and published in Endangered Species Research (https://www.int-res.com/abstracts/esr/v41/p197-207/). The poster and data analysis are available at https://figshare.com/projects/The_influence_of_Leave_No_Trace_ordinances_on_coastal_species_management/59132.
Effects of Leave No Trace ordinances on sea turtle nesting emergence in the Florida Panhandle
Increased human development of the coastal environment can place a significant strain on these ecosystems. These systems provide critical services including storm protection, tourism, wildlife viewing, and habitat for threatened species. Beach-nesting and -dwelling species such as sea turtles and shore/seabirds need clean beaches for successful reproduction. Leave No Trace ordinances may provide a mechanism for mitigating human-ecosystem conflicts in coastal environments by reducing abandoned beach equipment, physical damage to the environment, and interactions with marine debris.
This project reviewed existing Leave No Trace ordinances in the Florida Panhandle enacted over the last 10 years and was conducted as part of FSU’ Undergraduate Research Opportunity Program (UROP). It’s an expansion of the work previously conducted in Baldwin County, Alabama (Ware and Fuentes 2020) – investigating if these ordinances impact sea turtle nesting emergence and nesting success relative to pre-ordinance levels and to control sites pre- vs. post-ordinance.
Unfortunately, more work needs to be done – including better reporting of the cause of obstructed sea turtle crawls and the enforcement of enacted ordinances – before the effects of these ordinances in the Florida Panhandle can be fully evaluated.
- Ware M, Fuentes MMPB (2020) “Leave No Trace” ordinances for coastal species management: Influences on sea turtle nesting success. Endangered Species Research. DOI: 10.3354/esr01020.
https://www.int-res.com/abstracts/esr/v41/p197-207/
Review of microplastic sampling methods and impacts on marine organisms and environments
Microplastics (i.e., plastic debris smaller than 5 mm) have become ubiquitous in the marine environment. Whether manufactured at this size or a result of weathering in the environment, these contaminants can significantly impact marine systems. For example, microplastics can be ingested, impacting the gastrointestinal tracts of marine organisms and leaching toxicants which can effect immune or hormone functioning. When mixed into the sediment, they can alter the geochemical properties of the substrate such as heat conductance. Such impacts, and others, may pose a significant threat to marine species such as sea turtles which rely on a narrow range of environmental conditions for proper embryonic development and have been documented to frequently ingest this debris.
Many studies of this contamination do not use a standardized sampling, analysis, and/or reporting approach, complicating comparisons between these works. This project, undertaken as part of FSU’s Undergraduate Research Opportunity Program (UROP) started conducting a literature review of over 1,000 manuscripts, conference abstracts, and other available publication to assess the current state of microplastic contamination research and help provide standardized methods for future biological and environmental projects. This work has been paused until further notice.
