Climatic Niche Shifts During Biological Invasions Decrease With Genetic Diversity Loss

Climate niche conservatism is a fundamental assumption for predicting biological invasion risks and species range expansion under climate change. However, increasing evidence across taxa has revealed climatic niche shifts in species within new ranges. Although considerable effort has been made to identify ecological predictors of climatic niche shifts, the genetic process underlying species adaptation to novel climate niches is largely unknown. Here, on the basis of 84 introduction events with specific native population ranges for 38 non-native terrestrial vertebrates worldwide, we found that although invaders tend to show reduced genetic diversity after invasion, climate niche shifts are prone to occur when species have a relatively low reduction in genetic diversity in the non-native range. Interestingly, this effect of genetic diversity change on niche shifts did not occur through propagule pressure or residence time, which are traditionally speculated to influence niche shifts. Our study highlights the importance of incorporating ecological adaptation factors in the development of predictive models to evaluate the risks of biological invasion and species range expansion in the context of sustained global change.