Predicting the Potential Distribution of Three Allergenic Invasive Ambrosia (ragweed) Species in Asia

Three ragweed species native to North America (Ambrosia artemisiifolia L., A. psilostachya DC, and A. trifida L.) that have been introduced into Asia are now spreading quickly in many regions. Predicting which specific areas may be vulnerable to the invasion of these allergenic Ambrosia species can provide valuable insights for early detection and for prioritizing preventive actions. Species distribution models, based on native and non-Asian occurrence records for these three Ambrosia species, were generated with the maximum entropy (Maxent) approach respectively. Spatial filtering and target-group background methods were used to address sampling bias. Models fitted with different levels of complexity under present conditions were compared and evaluated with independent Asian records. Models showing lower over-fitting and higher performance were then selected to assess their future distribution under two types of Representative Concentration Pathways (RCP4.5 and RCP8.5), using four General Circulation Models (GCMs). Predicted habitats for A. artemisiifolia in 2050 would contract in regions having been colonized, despite a limited increase in parts of China. This species may experience a southward range shift in China. Under all future climate scenarios, A. trifida was predicted to decrease its potential establishment while A. psilostachya would expand its range, especially in habitats being colonized currently. Special attention should be given to Hunan, Jiangxi Provinces and scattered along southeastern coastal regions of China as well as parts of Turkey and northwest Iran, Azerbaijan, considering that future potential distribution of A. artemisiifolia and A. psilostachya might increase in these areas respectively. The findings provide valuable information for assessing the risk that these three Ambrosia species pose to many Asian countries and for prioritizing early detection and prevention strategies.