Out of sight, out of mind: Phylogenetic and taxonomic gaps imply great underestimations of the species’ vulnerability to global climate change

Abstract

The study of the species’ climatic niche is an excellent proxy of their vulnerability to global climate change. It is well known that species with greater niche marginality or a smaller niche breadth are most vulnerable to global climate change. However, these measures have never been contextualized regarding the shortfalls in biogeography: Linnean and Darwinian shortfalls. Here based on the study of Liolaemidae, one of the most diverse families of tetrapods, we showed that as phylogenetic and taxonomic knowledge accumulated across time and shortfalls filled up, the split of species complexes (previously recognized as single species) generates new species much more vulnerable to the effect of global climate change. We calculated and compared via Ecological Niche Factor Analyses (ENFA), Climate-Niche Factor Analysis (CNFA), and ellipsenm the marginality and breadth of climatic niches of five monophyletic groups of lizards, considering two stages in their taxonomic knowledge: the original described species (past period), and currently the updated species (2020 period). For both stages, we also estimated their climate change exposure and vulnerability. The climatic niche of the updated species (current, 2020) was significantly more marginal and smaller, and therefore their exposure and vulnerability to global climate change significantly more remarkable, than the originally described species (past periods). Our findings evidence that the real vulnerability of biodiversity to global climate, could be masked for the lack of taxonomic and phylogenetic knowledge, highlighting the great importance of these disciplines for species’ risk assessments. This fact is especially exacerbated in those poorly known or unstudied diverse groups and countries.