Sea turtles change nesting methods to cope with climate change

Researchers who tracked green turtles and big-headed turtles nesting in Cyprus have found that they return to their nesting sites earlier each year to avoid rising temperatures.

For sea turtles, temperature determines the biological sex of the hatchlings, with more females being born when it's warmer, and fewer hatchings succeeding when it's too hot. Turtles also have a "breeding migration," meaning they return to nest in the area where they were born.

Using data from three decades, a research team from the University of Exeter and the Turtle Conservation Society predicts that by 2100 virtually no big-headed turtles will be born, unless they combat higher temperatures by accelerating their nesting season.

After placing temperature recorders in the nests at night when the female turtles laid their eggs and collecting the eggs after hatching, researchers estimated that turtles need to nest 0.5 days earlier each year to maintain the current sex ratio and 0.7 days earlier each year to avoid unsuccessful hatching.

However, researchers' data suggests that big-headed turtles have actually been nesting earlier in the year, with females returning to nest 0.78 days earlier each year since 1993. This means that, at least for now, the turtles are doing enough to ensure their eggs continue to hatch by nesting earlier in more ideal temperatures.

The research team also published a study using 31 years of data on more than 600 individual green sea turtles nesting on the same beach in Northern Cyprus to see what factors influence when they begin laying eggs each year and how we can explain the progress we have seen over the past three decades.

Source: https://www.mard.gov.vn/Pages/rua-bien-thay-doi-cach-lam-to-de-ung-pho-voi-bien-doi-khi-hau.aspx