Potential distribution of the extremely endangered species Ostrya rehderiana (Betulaceae) in China under future climate change.

Global climate change is a major threat to biodiversity, which may increase the extinction risk of rare species, particularly those like Ostrya rehderiana Chun (Betulaceae) with very few remaining extant wild individuals. We aimed to estimate the potential distribution of O. rehderiana under climate change and to analyze possible relevant climatic factors. Maximum entropy (Maxent) was employed to model the potential distribution of O. rehderiana under present and future climate scenarios. Suitable habitat areas in different periods and the main contributing climate factors were identified using species distribution models. The minimum temperature in winter and precipitation seasonality were the principal climatic factors influencing the establishment of O. rehderiana. The proportion of high potential distribution area in China was 3.91% and would further shrink significantly under changing climate, especially reduce by 97% under high radiative forcing. The extinction risk of O. rehderiana would still be extraordinarily high under future climate scenarios. The Tianmu and Luoxiao Mountains would be the only potential refugia for O. rehderiana in the future. Special conservation efforts are urgently required to rescue extremely endangered species as O. rehderiana. We propose priorities for the conservation region and suggestions for conservation management strategies.