Anthropocene Imperilment of Ancient Diversity and Evolutionary Potential in Terrestrial Vertebrates

The ecological and evolutionary consequences of ongoing extinction episodes remain poorly understood1, despite mounting evidence of global biodiversity loss. To assess how human activities are reshaping tetrapod evolution, we estimate species-level extinction probabilities (‘pEX’) over the next ~50–500 years2,3 using time-calibrated phylogenies4–8, 35 ecological and environmental attributes9, and current-day, expert-assessed threats for 33,281 terrestrial vertebrates2. We find a critical, divergent association between extinction risk and macroevolutionary patterns10: in birds, lizards, and snakes, both evolutionary distinct and rapidly diversifying lineages are most imperiled; while in amphibians and mammals, threat is concentrated in less distinct and slowly radiating groups. Overall, species with high fecundity, intermediate body sizes, and broad geographic ranges are more likely to persist through the ongoing extinction crisis11–14. Without intervention, current-day threats alone suggest a 15% decline (~5,000 extinctions) in species richness and a 16% loss in median speciation rate from 0.11 to 0.094 lineages per million years within the next 500 years. Notably, mammals are projected to experience the largest declines in future speciation potential, despite lower overall imperilment than turtles, crocodilians, or amphibians. Across tetrapods, projected evolutionary distinct extinctions are concentrated in tropical regions, whereas faster-radiating lineages face widespread risk across deserts, tropical islands, and temperate zones. These results uncover ecological and evolutionary drivers of the ongoing reorganization of Earth’s biodiversity, underscoring the urgent need for coordinated conservation efforts to preserve both deep evolutionary history and future potential for evolutionary responses.