Predicting shifts in distribution range and niche breadth of plant species in contrasting arid environments under climate change.

Arid environments face extreme risk from contemporary climate change; therefore, predicting the shifts in species distribution range and niche breadth in these environments assumes urgent research priority. Here we report the potential distribution and predict future distribution range of two model plant species typically representing contrasting environments across Asia and Africa: hot-arid Ephedra foliata and cold-arid E. gerardiana. We adopted a comparative modelling approach and used occurrence points from extensive field surveys, supplemented with herbaria records and publicly available distribution data. Our study reveals that currently an area of 8.797334 × 10 km (8.8%) is potentially suitable for E. foliata and nearly half 4.759326 × 10 km (4.8%) for E. gerardiana. Under future climate change scenarios, distribution range of E. foliata is predicted to expand but contract in E. gerardiana. Similarly, E. foliata showed broader niche breadth which is predicted to increase under B1 (0.097-0.125) and B2 (0.878-0.930) climatic change scenarios. In contrast, E. gerardiana had narrower niche breadth and expected to further decrease under B1 (0.081-0.078) and B2 (0.878-0.854). The most influential bioclimatic variable governing the potential distribution and niche breadth of E. foliata was the precipitation of warmest quarter, whereas that of E. gerardiana was temperature seasonality. The results from our study can help in developing potential indicator plant species for assessment and monitoring of distribution range shifts in response to changing climate in the arid environments.