Prediction of the potential geographical distribution of Jujube witches'broom in China under climate change based on MaxEnt model
In this study,the MaxEnt model and ArcGIS software were used to predict the potential geographic distribution of jujube wit-ches'broom phytoplasma under historical and future climate scenarios,and the ROC curve was used to evaluate the accuracy of the MaxEnt model and to analyze the importance of 19 environmental variables using the knife-cut method to study the key environmental variables affecting the distribution of jujube witches'broom phytoplasma and the extent of their fitness zones.The results showed that the coldest monthly minimum temperature bio6,the seasonal variation of precipitation bio 15,the hottest season average temperature bio10,the isothermality bio3,the wettest season precipitation bio16,and the driest monthly precipitation bio14 were the key environmen-tal variables affecting the distribution of date madness phytoplasma,of which the coldest monthly minimum temperature had the greatest influence on the distribution of the potential fitness zone of jujube witches'broom phytoplasma.The mean AUC of the established Max-Ent model was 0.941,indicating that the prediction results were highly reliable.Under historical climate conditions,the total suitable ar-ea of jujube witches'broom phytoplasma was 2.208×106 km2,accounting for 23%of the total land area in China.The high suitable ar-eas were mainly distributed in central Beijing,all of Tianjin,central Shandong Province,northern Henan Province,eastern and southern Hebei Province,southwestern Shanxi Province,and eastern Shaanxi Province in China.Under two future climate scenarios,SSP126 and SSP585,the total suitable area of jujube witches'broom phytoplasma in China was 2.210×106 km2 and 2.386×106 km2,respectively;the difference between SSP 126 future climate scenario and historical climate conditions was not significant,and the increase between SSP585 future climate scenario and historical climate conditions.