Sophora alopecuroides is a perennial drought-tolerant leguminous herb mainly distributed in the northwestern region of China with important medicinal and foraging economic values. We explored the geographical distribution pattern and dominant environmental variables in populations of S. alopecuroides under various climate change scenarios using the MaxEnt model and ArcGIS. Our dataset comprises geographic distribution from 137 sites combined with a temporal element comprising past (Last Interglacial, Last Glacial Maximum, Mid-Holocene), current, and future (2050s, 2070s) predicted environmental variables under four CO2 representative concentration pathways. Results indicate that (1) the result by the MaxEnt model showed that the average Area Under the Curve (AUC) values exceeded 0.9, suggesting that the performance of our model was optimal and reliable; (2) annual mean temperature (bio1), temperature annual range (bio7), mean temperature of driest quarter (bio9), and elevation were the most important variables explaining the model; (3) under current climatic conditions, suitable habitat for S. alopecuroides accounted for 28.9% of the total area of China, which is consistent with the actual distribution of the species; (4) from the Last Interglacial to current period, the center of gravity for the distribution of suitable areas for S. alopecuroides has gradually shifted southeastward by a small distance in response to the ongoing increase in temperature, and is expected to shift northwestwards from the present to the 2050s to the 2070s; and that (5) the Loess Plateau and the Inner Mongolia Plateau may be the origin and are the modern distribution centers of S. alopecuroides.

Understanding the potential effects of climate change on species distribution is vital for the conservation of endangered taxa. The Saxifragaceae family, known to be susceptible to habitat disturbance, has a diverse distribution. While a significant portion is found on the Qinghai-Xizang Plateau (QXP), about half the species of Saxifraga are native to Europe, and other genera, such as Heuchera, have their centers of diversity in regions like North America and Japan. In this study, we employ the Maximum Entropy (MaxEnt) model in conjunction with Shared Socioeconomic Pathways (SSPs) to assess the MaxEnt potential influence of climate change on the distribution and richness of four endangered Saxifragaceae species (Saxifraga cernua L., Saxifraga tangutica Engl., Saxifraga przewalskii Engl. ex-Maxim., Saxifraga unguiculata Engl.) on the QXP, spanning time periods from the Last Glacial Maximum to 2080. Our results indicate that factors such as elevation, slope, mean annual temperature, isothermality, precipitation seasonality, and precipitation during the wettest quarter significantly affect species distribution patterns. Historical climate models demonstrate that approximately 30% of the QXP provided highly suitable habitat for Saxifragaceae species. Current projections suggest that this proportion has increased to over 30% and is anticipated to remain above 30% for the subsequent three-time intervals. Optimal habitats have been identified in southeastern QXP, western Sichuan, and northern Yunnan. The taxa are predicted to shift southward in response to future climate changes. Our findings underscore the importance of implementing conservation strategies that prioritize the establishment of protected areas in the southeastern QXP to safeguard these vulnerable Saxifragaceae species.