Male-producing beaches in the Pacific: crucial refuges for sea turtles facing climate change

Climate change poses a significant threat to sea turtle populations. Rising temperatures can exacerbate hatchling feminization, leading to markedly skewed sex ratio that may affect reproductive success and, consequently, the long-term viability of populations, as well as reduction in hatching success. In this context the main objectives of this study were to (1) determinate the current sex ratios and hatching success of Lepidochelys olivacea at two beaches of the eastern Pacific of Ecuador (from 2018 to 2020, and in 2022), (2) identify the main variables influencing hatching success, and (3) project the future nest temperature under three climate change scenarios. To achieve this, the relationship between nest and air temperatures was analyzed, and future nest temperatures were projected using CMIP6 climate scenarios (SSP1-2.6, SSP2-4.5, SSP5-8.5), accounting for uncertainties such as model variability and prediction errors. The results revealed average incubation temperatures of 27.0 °C (SD ± 0.52) in Portete and 27.3 °C (SD ± 0.50) in Galera, with mean hatching success rates of 85.4% and 60.0%, respectively. Analysis of sex ratios indicated consistently high male proportions across all nesting beaches and years, with values ranging from 0.85 to 0.99. Projections of nest temperature under three climate change scenarios suggested that male production will likely persist, even in the worst-case scenario, with probabilities of exceeding the pivotal temperature (30.5 °C) reaching 71% (Portete) and 68% (Galera) by 2080–2099. These findings underscore the importance of conserving “male refuges” to mitigate the impacts of climate change and support beach-specific conservation strategies that can serve as refuges against the potential effects of global warming.