The global protected area network is far from complete in representing species diversity, with 12% of all species not represented in any protected area. This study combines five global data sets to assess the effectiveness of protected areas in representing species diversity. It shows that current protected areas are inadequate, and uniform conservation targets based on percentage of area are insufficient. The results indicate that regions with higher levels of endemism require more protection, and that the current network is biased towards areas with higher species richness. The study emphasizes the need for conservation strategies that account for biodiversity patterns rather than relying on general percentage-based targets. Protected areas are cost-effective but not the only conservation tactic. The findings highlight the importance of focusing on regions with the greatest conservation needs and prioritizing those with the highest urgency for conservation action. The study also notes that the current network is significantly biased towards sites with higher richness of all species, restricted-range species, and threatened species. This may be due to decisions to locate some protected areas in better sites or higher levels of biodiversity loss outside protected areas. The study concludes that conservation strategies must address the complexity of natural ecosystems, including genetic and phylogenetic diversity, and ecological and evolutionary processes. The existing protected area network provides an invaluable service in shielding habitat from destructive use and reducing biodiversity loss. However, the global protected area network is still far from complete, even for terrestrial vertebrates. The study highlights the need for strategic expansion of the global protected area network to focus on regions that would contribute most to the global system and prioritize those with the greatest urgency for conservation action.The global protected area network is far from complete in representing species diversity, with 12% of all species not represented in any protected area. This study combines five global data sets to assess the effectiveness of protected areas in representing species diversity. It shows that current protected areas are inadequate, and uniform conservation targets based on percentage of area are insufficient. The results indicate that regions with higher levels of endemism require more protection, and that the current network is biased towards areas with higher species richness. The study emphasizes the need for conservation strategies that account for biodiversity patterns rather than relying on general percentage-based targets. Protected areas are cost-effective but not the only conservation tactic. The findings highlight the importance of focusing on regions with the greatest conservation needs and prioritizing those with the highest urgency for conservation action. The study also notes that the current network is significantly biased towards sites with higher richness of all species, restricted-range species, and threatened species. This may be due to decisions to locate some protected areas in better sites or higher levels of biodiversity loss outside protected areas. The study concludes that conservation strategies must address the complexity of natural ecosystems, including genetic and phylogenetic diversity, and ecological and evolutionary processes. The existing protected area network provides an invaluable service in shielding habitat from destructive use and reducing biodiversity loss. However, the global protected area network is still far from complete, even for terrestrial vertebrates. The study highlights the need for strategic expansion of the global protected area network to focus on regions that would contribute most to the global system and prioritize those with the greatest urgency for conservation action.