Cyprus: Turtles Adjust Nesting Habits in Response to Climate Change

Recent studies have highlighted a concerning trend among sea turtle populations in Cyprus, revealing their adaptive behaviors in the face of climate change. As rising beach temperatures threaten the survival of turtle eggs and potentially skew the gender ratio towards females, certain species are exhibiting a remarkable ability to modify their nesting patterns.

The research focused on two prominent species: the Loggerhead turtle (Caretta caretta) and the Green turtle (Chelonia mydas), both of which nest along the Alagadi beach in Northern Cyprus. The studies, conducted by teams from the UK and Cyprus, analyzed over three decades of nesting data to assess how these turtles are responding to increasing temperatures.

Changes in nesting behavior were particularly evident; the Loggerhead turtles have been laying their eggs an average of 0.5 days earlier each year to maintain a balanced sex ratio, and 0.7 days earlier to enhance hatching success. This adjustment is crucial, as the sex of turtle hatchlings is determined by the temperature at which the eggs are incubated. The research team reported that some of these turtles have been laying eggs increasingly earlier, with site-faithful individuals nesting approximately 0.78 days sooner annually.

Co-author Annette Broderick from the University of Exeter expressed optimism about these findings, indicating that the turtles' ability to shift their nesting timeline to cooler months is a positive sign of their resilience against the challenges posed by climate change.

However, the long-term sustainability of this adaptive behavior remains uncertain. As temperatures continue to rise, the turtles' capacity to adjust may be tested. Factors such as the availability of food, which is also subject to climate fluctuations, play a significant role in their nesting success. Loggerhead turtles can travel vast distances--hundreds to thousands of kilometers--to reach their feeding grounds, further complicating their survival amidst changing environmental conditions.

The Green turtles have also shown a similar trend; their nesting dates have shifted earlier by approximately 0.45 days each year since 1993. Researchers noted that the first nests of the season have been discovered 0.93 days earlier each year, although the timing of the last nests has remained relatively stable. This pattern correlates with rising sea temperatures, reinforcing the notion that these turtles are responding to their warming habitat.

It is important to note that these adjustments are not indicative of an evolutionary shift but rather a direct response from individual turtles to the changing environment. Given that the maturation period for these species can exceed 30 years, any genetic adaptations would require significantly longer timeframes to develop.

Despite the current adaptability displayed by these turtles, concerns persist regarding their future. With ongoing climate change, the suitability of nesting sites in Cyprus could diminish. Researchers suggest that, should conditions become untenable, turtles may need to migrate to cooler nesting grounds elsewhere in the Mediterranean.