Short-term resilience to climate-induced temperature increases for equatorial sea turtle populations

Area of Science:

• Marine Biology
• Climate Change Ecology
• Conservation Science

Background:

• Sea turtles exhibit temperature-dependent sex determination, making them vulnerable to climate change.
• Rising sand temperatures on nesting beaches can skew hatchling sex ratios towards females, threatening populations.
• Equatorial nesting sites are crucial for understanding climate change impacts on sea turtle reproduction.

Purpose of the Study:

• To model long-term trends in sand temperatures and hatchling sex ratios for green and hawksbill turtles at a Papua New Guinea nesting site.
• To assess the influence of climate change, specifically rising temperatures and rainfall patterns, on sea turtle reproductive success.
• To compare the projected impacts on this site with other known nesting locations.

Main Methods:

• Collected 1078 days of sand temperature data from 2018-2022 in Papua New Guinea at nest depth.
• Utilized a model with air temperature as a proxy to generate long-term sand temperature trends (1960-2019).
• Investigated the influence of rainfall and seasonal variations on sand temperature and projected future trends.

Main Results:

• Estimated a ~0.6°C increase in sand temperature between 1960 and 2019.
• Observed a relatively balanced average hatchling sex ratio (46.2% female) during this period.
• Projected future sex ratios (2020-2100) to become female-skewed (76%-87% female) without interventions.

Conclusions:

• The Papua New Guinea nesting site is currently less threatened by climate-induced feminization compared to other sites like Raine Island.
• While current sex ratios are balanced, future interventions may be necessary to ensure sufficient male hatchlings.
• This research advances understanding of climate change impacts on sea turtle populations through long-term trend analysis.