Are narrow-ranging species doomed to extinction? Projected dramatic decline in future climate suitability of two highly threatened species

Narrow-ranging species are usually omitted from Species distribution models (SDMs) due to statisti-cal constraints, while they are predicted to be particularly vulnerable to climate change. The recentlyavailable high-resolution environmental predictors, along with recently developed methods enable toincrease the eligibility of narrow-ranging species for SDMs, provided their distribution is well known. Wefill a gap of knowledge on the effect of predicted climate change on narrow-ranging species. We modelledthe distribution of the golden mantella frog Mantella aurantiaca and the Manapany day gecko Phelsumainexpectata, for which the distribution of their occurrence records is well documented. Our modellingscheme included a range of processes susceptible to address statistical issues related to narrow-rangingspecies. We predict an alarming decline in climate suitability in the whole current distribution areaof both species by 2070, potentially leading to a complete extinction in most scenarios. We identifiedthe areas with the best climate suitability in the future, but these remain largely suboptimal regarding modelsTranslocationspecies climatic niche. The high level of habitat fragmentation suggests that both species likely need to beat least partly translocated. Climate change may not only drive range contractions or distribution shifts innarrow-ranging species, but may lead to the complete extirpation of suitable environments across theirentire region. This study suggests that the level of threats of narrow-ranging species already identifiedas threatened may be underestimated, especially in heterogeneous tropical areas. We stress the need todevelop sampling campaigns and implement proactive actions for narrow-ranging species in the tropics.