3.3 Distribution range of the suitable areas of T. chinense under current climate conditions
Under the current climate conditions, the suitable area of the complete ecological niche of T. chinense is mainly distributed in three vegetation areas (Boreal forest, Temperate seasonal forest, and Shrubland) in the eastern of Asia (Figure 4A). The total area of suitable areas is about 734.53 * 104 km2, among which the high, medium, and low suitable areas are about 280.89 * 104 km2, 174.02 * 104 km2, and 279.62 * 104 km2, respectively. In China, the total area of the suitable areas of T. chinense is 509.26 * 104 km2, mainly distributed in the humid and semi-humid areas, with a small amount of distribution in the semi-arid area of northeast China (Figure 4B). The high suitable areas of T. chinense in China is approximately 273.72 * 104 km2, mainly distributed in the subtropical evergreen broad-leaved forest region, the warm temperate deciduous broad-leaved forest region, the temperate grassland region and the temperate coniferous and deciduous broad-leaved mixed forest region, accounting for 99.82% of the total area of high suitable areas, and a small amount of the tropical monsoon forests, rainforest region and the cold temperate coniferous forest region; The medium suitable areas are distributed around the high suitable areas, from the south to the subtropical evergreen broad-leaved forest region from the north to the cold temperate coniferous forest region were distributed in large numbers, with an area of about 131.00 * 104 km2; The low suitable areas is about 104.54 * 104 km2, which is mainly distributed in the subtropical evergreen broad-leaved forest region, the temperate grassland region and the high cold vegetation region on the Qinghai Tibet Plateau, accounting for about 36.82%, 27.99% and 13.17%, respectively (Figure 4C).