Wallacean shortfall is not reasonable for omitting poorly known species from the climate change agenda

Abstract

Climate change strongly affects species dynamics over spatial and temporal scales and serves as a major driver of future extinction risk. Conservationists have largely assessed the impacts of global warming on species with welldocumented distributions; however, poorly known species have often been excluded from the climate change agenda because of the Wallacean shortfall (incomplete knowledge of species’ geographic distributions). Here, we deconstruct this traditional argument by considering poorly known species in climate change research and proposing an integrative framework to assess their vulnerability by the end of the 21st century. By integrating trait-based and niche modeling approaches, we assessed the climatic vulnerability of seven poorly known anurans in terms of exposure, sensitivity, and adaptive capacity. The results showed that two species were classified as highly vulnerable, whereas three others were classified as potential adapters, potential persisters, or at high latent risk. These findings suggest that historically neglected species may face increasing vulnerability by the end of 2070. The study underscores the need to incorporate poorly known species in future climate change agendas, despite the persistent Wallacean shortfall.