Potential distribution
A. annua is an annual plant. Its native habitat was located in Asia, most likely in China. Now, it grew in every continent except Antarctic (Ferreira, Laughlin, Delabays, & de Magalhães, 2005). Accompany with development of cultivating techniques and growing demand of raw material for extracting artemisinin, it had been introduced in for experimental cultivation or adopted for breeding in non-native habitats(Ferreira et al., 2005; Woerdenbag et al., 1994). The simulation showed its high suitable habitat was located in many countries, such as USA, Brazil, Argentina, Australia, Malaysia, Vietnam, Thailand, Japan, Korea, India, Ukraine, Poland, Czech, Slovenia, Hungary, Romania, Austria, Italy, Sweden, German, France, UK, Madagascar, Tanzania, South Africa and so on(Laughlin, Heazlewood, & Beattie, 2002). It was in consistent with the distribution of its occurrence records. Compared with other similar studies, it showed that our simulation basically coincided with others(Qin, Jian, Jie, Chengzhong, & Caixiang, 2018; Wang, Li, Zeng, & Xie, 2015). But it was obvious that the high suitable habitat area in their study was bigger than that in ours(Ding et al., 2020). This may be caused by different quantity of adopted algorithms and occurrence records. Only boosted regression tree (BRT) was used in their research. The uncertainty of single model was unavoidable in that situation.