Modeling potential distribution of an endangered genus (Sinojackia) endemic to China

Sinojackia, a genus endemic to China, includes seven species with a small number of populations. To develop effective conservation measures, it is important to understand the potential distribution of endangered endemic plant species and the underlying environmental factors. Here, we collected extensive occurrence data of Sinojackia, and then extracted climate, soil, and vegetation data from several datasets. We utilized the species distribution model (MaxEnt) and ArcGIS to predict the current and future potential distributions (2050s and 2070s) of the genus, as well as changes in potential distribution areas in the future. We also analyzed the major environmental variables that affected the distribution of the genus. Results show that: (1) The current high suitability distribution areas are mainly located within the subtropical regions of China. Specifically, the Middle-Lower Yangtze River Plain, including most parts of Hunan, Zhejiang, the southern areas of Henan, Anhui, and Jiangsu, the areas around the Hubei and Jiangxi boundary, and some sporadic regions in Sichuan and Guizhou. The latitude spans 25.42° to 31.84°N. (2) In addition, the current high suitability distribution area (0.665) is extremely narrow, totaling 4.07×10⁴ km², accounting for 4.23% of the total area of China. Furthermore, suitable distribution will decline in the future (2050s and 2070s). Of note, the area under a RCP8.5 emissions scenario in the 2070s will be substantially reduced. (3) With the increase in temperature in the future, the genus will migrate to higher altitudes. Our results are critical for the establishment of nature reserves for in-situ conservation and for the selection of sites for ex-situ conservation.