Studies on Geographical Distribution Prediction of <i>Cirtus caraleriei </i>in China and Influences of Climate Change

The species <i>Citrus cavaleriei </i>Levl. ex Cavaler. is an unique wild <i>Citrus </i>germplasm resource with strong cold-resistance in China. The purpose of this paper is to understand the suitable areas of growth of <i>C. cavaleriei</i> in China and the influence of different climate change scenarios on its geographical distribution, and to provide reference for the development and protection of <i>C. cavaleriei</i> resources. Combined with the environmental data of different periods, this paper uses MaxEnt model to predict the suitable growing areas of <i>C. cavaleriei</i> in different periods in China, and uses ArcGIS software and SDMtools to analyze the changing characteristics of suitable growing areas and centroid migration routes of <i>C. cavaleriei</i> in different periods. The average AUC values are all larger than 0.95. The modeling results meet excellent standards. At present, <i>C. cavaleriei</i> is mainly distributed in Yunnan, Sichuan, Chongqing, Hubei, Guizhou, Hunan, Guangxi, Gansu, and Shanxi provinces in China. Under the benchmark climatic conditions, the total suitable area of <i>C. cavaleriei</i> in China is 144.82×10⁴km², among which the most suitable areas are mainly located in Guizhou, Chongqing, Sichuan and Hunan provinces. In 2050, under RCP4.5 and RCP8.5 scenarios, the suitable area of <i>C. cavaleriei</i> in China will increase by 22.20×10⁴km² and 29.80×10⁴ km²; respectively compared with that under the reference climate. With climate change, under RCP4.5 and RCP8.5 scenarios in 2070, the suitable area of <i>C. cavaleriei</i> in China has shrunk compared with that in 2050. Compared with the same scenario in 2050, the shrinking area is 81.76×10⁴ km² (RCP4.5) and 12.17×10⁴ km² (RCP8.5), respectively. RCP8.5 scenario is more beneficial to <i>C. cavaleriei</i> from the baseline climate to the next 2050 and 2070, the centroid of <i>C. cavaleriei</i> suitable area first moved eastward and then moved southwest, and the migration distance in RCP8.5 scenario was greater than that in RCP4.5 scenario.