Aim: The conservatism of realized climatic niche is a pivotal assumption for predicting invasion risk under present and future climate, but to date, no study has examined which dimensions of realized climatic niches are spatially and temporally conserved for a whole taxonomic group at a global scale. Understanding realized niche dynamics along each individual climatic variable separately is key to improving forecasts of invasive species distributions and anticipating future spreads.
Location: Global.
Methods: Using 181 successful invasion events for 128 alien herpetofaunal species across the globe, we apply a robust niche dynamics framework and analyse the conservatism of realized climatic niche and their influencing factors along different 19 temperature and precipitation variables.
Results: We find that the magnitude of the niche shift along the maximum temperature of the warmest month (or warmest quarter) is on average the lowest compared with minimum, average, range and seasonal temperature characteristics and all precipitation variables. Furthermore, the amount of niche shift along the maximum temperatures is only negatively correlated with native range size and is unrelated to residence time, species traits, introduction propagule pressure, topographic heterogeneity, or equatorward and poleward range expansion.
Main Conclusions: We provide the first evidence that the realized climatic niche of alien herpetofaunal species is generally most conserved along maximum temperatures. This finding highlights the importance of preferentially choosing conserved climatic niches to develop robust predictions of biological invasions or responses to climate change.