Ecological distinctiveness of birds and mammals at the global scale

Ecologically distinct species - species with distinct trait combinations - are not directly prioritized in current conservation frameworks. The consequence of this blind spot means species with the most distinct ecological strategies might be lost. Here, we quantify ecological distinctiveness, based on six traits, for 10,960 bird and 5,278 mammal species, summarizing species-level ecological irreplaceability. We find that threatened birds and mammals are, on average, more ecologically distinct. Specific examples of ecologically distinct and highly threatened species are Great Indian Bustard, Amsterdam Albatross, Asian Elephant and Sumatran Rhinoceros. These species have potentially irreplaceable ecological roles and their loss could undermine the integrity of ecological processes and functions. Yet, we also identify ecologically distinct widespread generalists, such as Lesser Black-backed Gull and Wild Boar. These generalist species have distinct ecological strategies that allow them to thrive across multiple environments. Thus, we suggest that high ecological distinctiveness is associated with either high extinction risk or successful hyper-generalism. We also find that ecologically distinct species are generally charismatic (using a previous measure of public perceptions of charisma). We thus highlight a conservation opportunity: capitalizing on public preferences for charismatic species could provide support for the conservation of the most ecologically distinct birds and mammals. Overall, our prioritization framework supports the conservation of species with irreplaceable ecological strategies, complementing existing frameworks that target extinction risk and evolutionary distinctiveness.