3.2. Potential geographical distribution of Leonurus japonicus in China
The Maxent model was used to simulate the distribution map of the suitable area of L. japonicus in the current period (Figure 3). The area highly suitable for L. japonicus in the current period was 135,620 km2; the moderately suitable area was 1,043,933 km2; and the low suitable area was 1,202,780 km2. These areas were distributed in 27 provinces and cities: Shanxi, Shaanxi, Shandong, Henan, Jiangsu, Zhejiang, Anhui, Hubei, Chongqing, Sichuan, Yunnan, Guizhou, Jiangxi, Fujian, Guangxi, Guangdong, and other places. Highly suitable areas were concentrated in southwestern Hubei, western Guangxi, southeastern and northwestern Zhejiang, northeastern Guangdong, southern Fujian, eastern Hunan, and southwestern Jiangxi.
3.3. Prediction of suitable growing areas for Leonurus japonicusunder future climate scenarios
Under the future climate scenarios, the predicted total suitable area ofL. japonicus in the 2050s and 2090s would be reduced by varying degrees compared with the current period (Table 3). In the 2050s, compared with the current period, the total suitable area of L. japonicus decreased under ssp126, ssp245, and ssp585 scenarios, with decreases of 31.38%, 26.25%, and 45.10%, respectively. Compared with the 2050s, the total suitable area in the 2090s showed a downward trend under ssp245 and ssp585 scenarios, with decreases of 14.89% and 38.64%, respectively, while increasing significantly under the ssp126 scenario to 359,474 km2, 22.00% higher than that in the 2050s.
Table 3 Suitable growing area of Leonurus japonicus in China, under different climate
scenarios in the future Km2