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Green Sea Turtles Adjust Nesting Patterns to Combat Climate Change

As global temperatures rise, green sea turtles are altering their nesting schedules to adapt to the shifting climate. Research published in the February issue of Proceedings of the Royal Society B indicates that female turtles are laying their eggs significantly earlier in the season due to warmer conditions. This behavioral change is essential for the survival of the species, as it seeks to mitigate the impacts of climate change.

Historically, the sex of turtles has been influenced by the temperature at which their eggs are incubated—warmer temperatures produce female turtles, while lower temperatures favor males. This shift in gender ratio, driven by climate change, poses risks to turtle populations, including potential declines in genetic diversity as more females are born and fewer males hatch. Moreover, extreme heat can be detrimental to the eggs, reducing hatchling survival rates.

To better understand these adaptations, a team led by conservation ecologist Annette Broderick examined three decades of nesting data collected from approximately 600 tagged green turtles (Chelonia mydas) along the Northern Cyprus beaches. Their analysis, which considered factors such as successful hatchling counts and incubation temperatures, revealed an alarming trend: as temperature increased by each degree Celsius, female turtles nested over six days earlier on average.

This research marks a significant advancement in how scientists view turtle nesting behavior. Broderick noted that it is the first study to focus on individual turtles rather than general population behaviors. “This approach allows us to draw more accurate conclusions about their adaptive strategies,” she explained.

While earlier studies have indicated shifts in nesting behavior among larger populations, this new evidence shows that it is not merely statistical averages being affected. Instead, every female turtle is changing her nesting timing in response to environmental cues. Mollie Rickwood, a marine biologist and co-author of the study, emphasized this point, stating, “While it might seem like an obvious conclusion, it is, in fact, a complex issue since population-wide changes could be influenced by various factors.”

Broderick further elaborated that factors like breeding experience and the number of clutches a female lays in a season also play crucial roles in determining nesting timing. Various studies indicate that the observed shifts in nesting could help offset the impacts of increasing temperatures on egg viability, offering hope for these marine reptiles.

Rickwood concluded, “Adjustments in nesting behavior present a more optimistic outlook for green sea turtles amidst the ongoing challenges posed by climate change.” By adapting to their changing environment, these turtles may enhance their chances of survival and maintain their ecological roles in marine ecosystems.

Source
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