Data from: Climate warming and sea turtle sex ratios across the globe

Climate warming and the feminisation of populations due to
temperature-dependent sex determination may threaten sea turtles with
extinction. To identify sites of heightened risk, we examined sex ratio
data and patterns of climate change over multiple decades for 64 nesting
sites spread across the globe. Over the last 62 years the mean change in
air temperature was 0.85 °C per century (SD = 0.65 °C, range = -0.53 to
+2.5 °C, n = 64 nesting sites). Temperatures increased at 40 of the 64
study sites. Female-skewed hatchling or juvenile sex ratios occurred at 57
of the 64 sites, with skews > 90% female at 17 sites. We did not
uncover a relationship between the extent of warming and sex ratio (r62 =
-0.03, p = 0.802, n = 64 nesting sites). Hence, our results
suggest that female-hatchling sex ratio skews are not simply a consequence
of recent warming but have likely persisted at some sites for many
decades. So other factors aside from recent warming must drive these
variations in sex ratios across nesting sites, such as variations in
nesting behaviour (e.g., nest depth), substrate (e.g., sand albedo),
shading available and rainfall patterns. While overall across sites recent
warming is not linked to hatchling sex ratio, at some sites there is both
is a high female skew and high warming, such as Raine Island (Australia;
99% female green turtles; 1.27 °C warming per century), nesting beaches in
Cyprus (97.1% female green turtles; 1.68 °C warming per century), and in
the Dutch Caribbean (St Eustatius; 91.5% female leatherback turtles; 1.15
°C warming per century). These may be among the first sites where
management intervention is needed to increase male
production. Continued monitoring of sand temperatures and sex
ratios are recommended to help identify when high incubation temperatures
threaten population viability.