Climate Change and Coastal Development Will Affect US Sea Turtles

Climate change and coastal development will lead to a less suitable nesting habitat for sea turtles in the United States, reports a new study by researchers from Florida State University.

The study findings indicate that areas remaining or turning suitable for nesting of sea turtles in the future due to sea-level rise and climate changes will be susceptible to increased coastal development. This would inhibit the ability of turtles to adapt to such disturbances. The study was published recently in the Regional Environmental Change journal.

A reduction in available nesting habitat coupled with the pressures associated with coastal development could likely have detrimental impacts on the reproductive output of sea turtle nesting areas in the U.S. and population stability.

Mariana Fuentes, Associate Professor of Oceanography, Department of Earth, Ocean and Atmospheric Science, Florida State University

Fuentes is the lead author of the study. The team created models for the suitability of coastal habitats in the eastern United States by 2050 for the nesting of leatherback, green, and loggerhead sea turtles, with respect to estimated sea-level rise and future climates.

Although there is a difference in outcomes for particular species and places, the overall picture points toward decreases in suitable nesting grounds and an increase in pressure due to coastal development.

Loggerhead turtles will face an approximately 10% decrease in suitable nesting areas, with worsening conditions in Florida, North Carolina, and South Carolina. Although Green turtles will face some enhanced nesting habitat in southwest Florida, they will see less suitable habitat in the Carolinas and elsewhere in the state.

In general, green turtles will face an approximately 7% decrease in suitable nesting habitat along the East Coast of the United States. Leatherback turtles will not evidence substantial variations in the wider availability of suitable areas.

Rising sea levels, changing climate, and coastal development each have a role to play in establishing the availability of suitable nesting habitats in the future.

Sea turtles necessitate specific climate conditions for the incubation of eggs, and a changing climate will imply different conditions for temperature and precipitation. Another factor is the rise in sea level. Researchers have estimated that nearly 80% of the current habitat—projected to have a suitable climate for incubation of eggs in the future—would submerge.

However, it has also been predicted that sea-level rise will create new beaches. A 0.5-m rise in sea-level (a conservative estimate) is projected to lead to a net habitat gain for the sea turtle species studied by the team. But coastal development will pose a problem in a majority of those areas, which will affect how well they work as nesting sites.

The team discovered that some of the regions in North Carolina and South Carolina, which are predicted to have high or very high climate suitability for incubation of sea turtle eggs, face little risk due to sea-level rise and no significant housing growth, which will render them as ideal nesting habitats. Recognizing these areas could help create suitable management and conservation policies.

In other places where the researchers anticipate that development will add pressure to sea turtles, management approaches—such as turtle-friendly lighting, not disturbing nesting areas, and eliminating beach debris—will help reduce further effects of human activity on these animals.

Sea turtles have existed for millions of years, and they have persisted through dramatic changes in climate in the past. They have the ability to adapt to changing conditions, but coastal development and the unprecedented speed of current climate change are things they have never had to deal with, which may hinder their ability to adapt to the future.

Mariana Fuentes, Associate Professor of Oceanography, Department of Earth, Ocean and Atmospheric Science, Florida State University

Other contributors to the study were researchers from the U.S. Fish and Wildlife Service, Florida Fish and Wildlife Conservation Commission, North Carolina Wildlife Resources Commission, the Padre Island National Seashore Division of Sea Turtle Science and Recovery, University of Wisconsin-Madison, Deepwater Horizon Gulf Restoration Office, South Carolina Department of Natural Resources, and the National Audubon Society.

Journal Reference:

Fuentes, M. M. P. B., et al. (2020) Potential adaptability of marine turtles to climate change may be hindered by coastal development in the USA. Regional Environmental Change. doi.org/10.1007/s10113-020-01689-4.