Potential Distribution Pattern Of Invasive Species Amaranthus Retroflexus L.in Xinjiang Under Climate Change

Alien invasive plants threaten the original biogeographical distribution pattern and natural ecosystems just as pathogens invade the human body,and their superimposition with increasingly severe global climate change will create more difficult ecological and environmental problems.Scientific prediction under climate change scenarios is an effective means to analyze,evaluate,and prevent the invasion of alien organisms at the lowest cost.It can provide data foundation and theoretical basis for early warning and prevention and control of invasive species.This article takes the global widespread Amaranthus retroflexus L.as the research object,and uses China's westward-opening gateway and frontier core province Xinjiang as the research area.The deterministic climate scenario RCP4 released by the IPCC definition.5.RCP6.0and RCP8.5 are the main driving forces.Through 15 pre-processed environmental variables,the R-based Bio Mod2 integrated model platform and Max Ent model are used to change habitats from suitable habitat boundaries and migrations,area spatial changes,and climate change.Potential distribution of invasive species in Xinjiang under climate change scenarios from multiple perspectives,such as response,distribution center of mass centroid movement path,single and combined prediction methods,model strengths and weaknesses,analysis of dominant environmental variables,invasion risk assessment,and control measures A comprehensive forecasting study was conducted on the pattern.The main conclusions are as follows:By comparing ROC,KAPPA,TSS and other three model evaluation indicators to compare GLM,GBM,GAM,CTA,ANN,SRE,RF and other single prediction models and EM combined prediction models in the Bio Mod2 integrated model platform,we found that the comprehensive prediction ability and stability Excellent is the RF model.The suitable habitats of the anti-scourges predicted in the current period are located along the Altai Mountains in the north,along the Kunlun Mountains in the south,in the Hami region in the east,and in Kuzhou in the west,in the northwest of Tacheng,Karamay,Shihezi,and Bozhou.Central and central Yili Prefecture are highly suitable habitats.The range of suitable habitats predicted by the combined prediction model EM has shrunk.The areas with higher suitability indexes are mainly located in the northern margin of the Tarim Basin and the eastern side of the Tianshan Mountains.The southern boundary excludes the area between the Taklimakan Desert and the northern foothills of Kunlun Mountain.In the future climate scenarios,suitable habitats of A.chinensis have not undergone significant migration,and the distribution pattern has generally stabilized,but the habitat suitability index in some regions has been improved under the RCP4.5,RCP6.0,and RCP8.5 scenarios to 2070 s.The AUC values of the Max Ent model training data set and test data set under current and future climate scenarios are 0.943 and 0.940,achieving excellent prediction confidence.The suitable habitats predicted in the current period are mainly located in the southern foothills of the Altai Mountains and the northern foothills of the Tianshan Mountains in northern Xinjiang.With the warming of the climate,the expansion of suitable habitats of Acanthopanax senticosus has a positive correlation with the CO2 emissions of typical concentration paths.The boundary was expanded to Yiwu County in the Hami region,and the western boundary was extended to Shufu County in the Kashi region.At the same time,the fitness of A.chinensis in Altay,Tacheng,Bozhou,Ili,and the northern slope of the Tianshan Economic Belt Significantly enhanced.Under the RCP8.5 scenario,the area expanded in 2070 s is 1.75 times that in 2050 s,which has the most significant impact.The Bio Mod2 model and the Max Ent model are highly consistent and point out that the driest month rainfall and total nitrogen are the key environmental variables that affect the geographical distribution of Acanthopanax,and their existence probability is when the driest month rainfall(55.2%)reaches 22 mm and total nitrogen(12.7%)Reached the highest value at 1.0g / kg and tended to be stable.Under the background of climate change,Shawan County,located in the northern foothills of the Tianshan Mountains,is the central area of the spread of Amaranthus retroflexus.With the continuous increase of temperature and the passage of time,the risk of invasion to the southeast and southwest will continue to increase.Comprehensive evaluation identified Amaranthus retroflexus as a high-risk invasive plant in the Xinjiang region under the background of climate change.This species has great potential for spreading to southern Xinjiang based on the existing region.The Amaranth in Xinjiang region may show explosive growth in the latter half of this century.Early warning should be given to high-risk areas where the fitness of A.chinensis has been significantly enhanced under the background of climate change,and the existing distribution areas should be eradicated in a timely manner,and diffusion restrained.Prevention and control work should be considered in a unified manner,comprehensively consider its own application value,and reduce costs and difficulties with minimal environmental and resource costs.When using the niche model,you should choose according to your own data conditions and research needs.It is recommended to use multiple models for comprehensive cross-analysis and prediction to break the limitations of a single model.