Data from: Local adaptation may help mitigate feminisation of sea turtle populations globally

Climate warming currently threatens many species with extinction,
particularly those with a limited capacity for adaptation. Sea turtles
have temperature-dependent sex determination, whereby female hatchlings
are produced at warmer incubation temperatures, and hence climate warming
might cause the feminisation of populations. Recent evidence suggests that
climate warming will outpace the ability of turtles to adapt through
phenological shifts in nesting. Here, we examine 138 published estimates
for hatchling sex ratios spanning the 7 sea turtle species and all ocean
basins. We evaluate whether turtles have the capacity to adapt to warming
temperatures through local adaptations of the pivotal temperature at which
they produce a balanced amount of male and female hatchlings. We show that
at warmer sites, lower proportions of female hatchlings are produced than
expected from generalised sex ratio versus incubation temperature
relationships that have been previously used across all sea turtle
species. This points to local adaptation of the pivotal temperature (i.e.,
the temperature at which a balanced hatchling sex ratio is produced) as
evidenced by an analysis of 33 pivotal temperatures recorded at sites
around the world, that showed generally higher pivotal temperatures at
warmer sites, confirming previous work. These findings point to local
adaptation of the pivotal temperatures, which could help the production of
male hatchlings at warmer sites and so assist with population viability.
These results suggest that sea turtle hatchling sex ratio is more
resilient to climate change than previously thought.