Global assessment of current extinction risks and future challenges for turtles and tortoises

Turtles and tortoises (chelonians) are among the most threatened vertebrates worldwide, yet the factors determining their high extinction risk and their resilience to further challenges are not fully understood. Here, we compile a dataset comprising intrinsic and extrinsic variables for chelonians to reveal their current risk patterns and extinction vulnerability to future climatic and anthropogenic threats. The results show that at-risk species are predominantly characterized by large body size, small ranges, high functional distinctness, and intense human threat levels, with high representation in the Indomalayan region. Notably, 18.6% of currently unevaluated species are projected to be threatened with extinction. Furthermore, the projected rates of climatic and environmental changes across species' distributions are significantly higher than the rates of evolution for traits linked to resilience to climate change and altered environments. Overall, this study provides insights for prioritizing conservation actions and underscores the urgent need to prevent future extinctions of chelonians.