Suitable Areas And Risk Analysis Of Several Invasive Plants In Yili Region

Pest invasion, as one of the important elements of the earth’s environment change, havecaused great damages to the world economy and ecological environment. Invasive specieswill damage local ecological environment in a certain degree, and affect the ecosystemprocesses, cause certain kinds of plant diseases and insect pests, reduce the native speciesbiodiversity, and also lead other native species to extinction. Therefore, the study of invasivespecies has attracted worldwide attention.China is a country with vast land, rich resources, at present the alien species which hassuccessfully invaded to China has reached nearly300species, and the economic loss causedby them is about120billion Yuan according to statistics. However, studies on alien species inChina starts late, and the progress is slow, especially in Xinjiang, not any systematic researchon the invasive species has been took place. In this paper Ili region has been taken as thestudy area to predict the suitable distribution extension of Xanthium Italicum,Cannabis_sativa_L, Amaranthus retroflexus L, Xanthium spinosum using the niche modelMaxent. The results showed that:(1) Most of the regions of each counties and cities in Ili, except the surroundedmountainous areas namely Koksheng, Erenhaber, Narat, Usun, are suitable for Xanthiumitalicum. The AUC value for training set of the Maxent is0.959; for testing set is0.931, whichmeans the prediction is similar to the reality.(2) The suitable area of Cannabis sativa L. is as wide as Xanthium italicum, in contrast,Cannabis sativa L. with less suitable area than Xanthium italicum. AUC value for Modeltraining set is0.956, testing AUC value is0.970.(3) Counties as Huo Cheng, Cha Bu Cha Er, Yi Ning of Ili are the most suitable areas forAmaranthus retroflexus L; Most of the areas of Gong Liu and Xin Yuan counties and smallpart of Te Ke Si are mid-suitable regions for it; Most of the Te Ke Si, Zhao Su and NiLeKeare the low suitable counties. The high suitable areas of Amaranthus retroflexus L are relatively concentrated, and anatomies with the on-the-spot investigation. AUC value ofModel training set is0.850, for testing set, AUC value is0.882(4) None mountainous areas of Ili are with high suitable rate for Xanthium spinosum,which is relatively consistent with field survey results. HuoCheng, YiNingXian, Cha Bu ChaEr counties are the high suitable areas, and as discovered in field trip, Xanthium spinosumspread more seriously in the Huo Cheng county and in other counties and cities are in a periodof stagnation, which should cause a certain attention. AUC value for Model training set is0.849; for testing set is0.832.This research, according to the requirement of the pest risk assessment system of China,established the risk assessment index system of Xanthium italicum after predicting thesuitable range of four types of plants, which combined with the situation of the Ili region.Using qualitative and quantitative method effectively for all levels of indicators’ assignment,results showed that: the risk value of Xanthium italicum in Ili region is60.3%, it will causehuge economic and environment losses to Ili region.