Trait-Associated Gaps in IUCN Assessment and Conservation Prioritization for Echolocating Mammals

Echolocating mammals comprise an evolutionarily and functionally distinct group of often cryptic species that navigate using ultrasound, of which many terrestrial representatives are nocturnal. We show that, compared to non-echolocators, these species are disproportionately represented in data-deficient or unevaluated IUCN categories, due to fewer population studies. This pattern is associated with ecological and socioeconomic correlates of detectability and research effort, including occurrence in less accessible habitats (e.g., caves and open ocean), smaller population sizes, restricted areas of occupancy, and lower national economic prosperity. We recommend that, given their evolutionary and functional distinctiveness, high taxonomic richness (particularly in bats), and important ecosystem functions, echolocators warrant greater IUCN assessment and elevated conservation priority, especially considering the ongoing threats that they face.