3.2 Important environmental variables
FIGURE S1 Jackknife test of important environment variables forSatyrium ciliatum , Satyrium nepalense , and Satyrium yunnanense
The jackknife test results indicated that the top three environmental variables with the largest effect on regularized training gains were as follows: isothermality (bio3), temperature seasonality (bio4), and mean temperature of coldest quarter (bio11) for S. ciliatum ; isothermality (bio3), temperature seasonality (bio4), and precipitation of the coldest quarter (bio19) for S. nepalense ; isothermality (bio3), temperature seasonality (bio4), and lower temperature of coldest month (bio6) for S. yunnanense when modeling with a single environmental variable (Figure S1). The contribution rate of environmental variables could also be used to evaluate each environment’s importance. The contribution rate of each variable was combined with the distribution of Satyrium species (Table 1). Isothermality (bio3, 52%) and temperature seasonality (bio4, 12.7%) for S. ciliatum reached 64.7%. Isothermality (bio3, 61.8%) and temperature seasonality (bio4, 14%) for S. nepalense reached 75.8%, much greater than the other contribution rates. Isothermality (bio3, 28.6%) and lower temperature of coldest month (bio6, 54.3%) for S. yunnanensereached 82.9%. The major environmental variables influencing the geographical distribution of S. ciliatum were isothermality (bio3), temperature seasonality (bio4), and mean temperature of coldest quarter (bio11). Environmental variables like isothermality (bio3), temperature seasonality (bio4), and precipitation of coldest quarter (bio19) affected the geographical distribution of S. nepalense ; and environmental variables like isothermality (bio3), temperature seasonality (bio4), and lower temperature of coldest month (bio6) affected the geographical distribution of S. yunnanense .
FIGURE S2 Probability of response curves for presence ofSatyrium ciliatum, Satyrium nepalense, and Satyrium yunnanense
The response curve was used to calculate the thresholds (existence probability > 0.5) for the main bioclimatic parameters (Figure S2) (Guo et al., 2017). For S. ciliatum , isothermality (bio3) ranged from 44 to 51.5, temperature seasonality (bio4) ranged from 420 to 580, and mean temperature of coldest quarter (bio11) ranged from 1℃ to 13℃. For S. nepalense , isothermality (bio3) ranged from 44 to 53, temperature seasonality (bio4) ranged from 400 to 580, and precipitation of coldest quarter (bio19) ranged from 25 to 80 mm. For S. yunnanense , isothermality (bio3) ranged from 41 to 53, temperature seasonality (bio4) ranged from 300 to 600, and lower temperature of coldest month (bio6) ranged from -6 to 6℃.
3.3 Current potential distributionsof S. ciliatum, S. nepalense, and S. yunnanense
FIGURE 4 Potential current and suitable habitats for Satyrium ciliatum ,Satyrium nepalense , and Satyrium yunnanense in China
As Figure 4 shows, S. ciliatum is mainly distributed in Southwest China. Highly suitable habitats are located at the border of Yunnan and Sichuan. Eastern Yunnan and Southern Sichuan have moderately suitable habitats. Poorly suitable habitats cover a broad area, primarily in Northern and Central Yunnan, Southern Tibet, Western Sichuan, and Western Guizhou. There is also a sporadic distribution in Western Guangxi. S. nepalense is mainly distributed in Southwest China. Highly suitable habitats are distributed in Central Yunnan. Western and Eastern Yunnan, as well as Southern Sichuan, have moderately suitable habitats. Poorly suitable habitats are located in Southern Yunnan, Western and Southern Sichuan, Southern Tibet, Western Sichuan, and Western Guangxi. S. yunnanense is mainly distributed in Southwest China. Highly suitable habitats are distributed in Yunnan. Moderately suitable habitats are located at the border of Yunnan, Guizhou, and Sichuan. Poorly suitable habitats are distributed in Western Guizhou, Central Sichuan, Southern Shaanxi, Western Henan, Southern Fujian, Southern Tibet, and Western Guangxi. The total suitable area forS. yunnanense is more than that of S. nepalense andS. ciliatum according to the mentioned climatic conditions, and these areas account for 9.35%, 6.43% and 3.39%, respectively, of the total land area of China (960×104km2).