Prediction Of Geographical Distribution Of Erannis Jacobsoni Djak In Mongolia Plateau Under Different Climate Conditions

The Mongolian Plateau is the most important ecological barrier in Asia.In recent years,due to the tension between man and land and the serious imbalance of the ecosystem,it has attracted widespread attention from the international community.Ecological protection is very important to forest ecological protection.The Mongolian Plateau is rich in forest resources,but the frequent occurrence of forest pests poses a great threat to the forest ecosystem.The Erannis Jacobsoni Djak glutinously feed on needles and cause the deciduous leaves to fall continuously,and eventually lead to the death of forest trees.It has become one of the most threatening pests to the forest ecosystem in Mongolia.The pests is currently mainly distributed in the larch forests of Hangai Mountain and Kent Mountain,showing a trend of spreading from northwest to southeast.The forest area of Greater Khingan in China is fully equipped with the suitable conditions for Erannis Jacobsoni Djak,and the risk of invasion is extremely high.Therefore,the study on the prediction of the potential distribution of Erannis Jacobsoni Djak is imminent.Based on the field survey statistics of the members of the Institute of Geography and Geology of the Mongolian National Academy of Sciences and the project team members of the Geographical Science Institute of Inner Mongolia Normal University,a total of 489 distribution points of Erannis Jacobsoni Djak were obtained.Based on the Max Ent 3.4.1ecological niche model,the current climate conditions habitat variables and three emission scenarios(ssp126,ssp245 and ssp585)of the global future climate model(Beijing Climate Center Climate System Model,BCC-CSM2-MR)in the 2021-2040s and 2041-2060s are used to predict the potential geographic distribution of Erannis Jacobsoni Djak in the Mongolian Plateau.Arc GIS 10.4 was used to analyze the area and change law of the potential geographic distribution area of Erannis Jacobsoni Djak under different climatic conditions.The knife-cut method and the receiver operating characteristic curve(ROC)area under curve(AUC)were used to evaluate the accuracy of the prediction model and the importance of habitat variables.The results of the study are as follows:(1)Under current climatic conditions,the high-level potential distribution areas of Erannis Jacobsoni Djak in the Mongolian Plateau are mainly located in the central and northern parts of the Central Province,the central and western parts of Kent Province,the northern part of Ulaanbaatar,the northwestern part of Qianhangai Province,the Houhangai Province,and Burgan.The central part of the province and the northeastern part of the Kusugul province.Among them,there are large contiguous high-level potential distribution areas in the Qianhangai Province,the Houhangai Province and the Burgan Province.The middle and low-level potential distribution areas of Central Province,Ulaanbaatar and Kent Provinces are spreading eastward.(2)The knife-cutting method results show that in the prediction of the potential geographic distribution area of Erannis Jacobsoni Djak under the current climatic conditions,bio3(monthly mean value of temperature difference between day and night /(highest temperature in the hottest month-lowest temperature in the coldest month)),bio10(warmest season)The cumulative contribution rate of bio18(precipitation in the warmest quarter),soilwater(soil moisture),vapr(vapor pressure)and bio1(annual average temperature)is 82.4%.Erannis Jacobsoni Djak first appeared in May.In June,they fed on needles and caused deciduous trees.In July,they molted 4 times and then fell into the soil to pupate.After the adult appeared in September,the female lays eggs in the cracks in the bark,overwintering with the eggs,repeating the cycle.The monthly average of the temperature difference between day and night,the lowest temperature of the coldest month,the highest temperature of the warmest month,the precipitation of the warmest season,the average temperature of the warmest season,soil moisture and water vapor pressure and other habitat factors affect the development stages of incubation period,pupation period and spawning period of Erannis Jacobsoni Djak,and are important factors for predicting its potential geographic distribution.(3)Under the ssp126,ssp245 and ssp585 climate scenarios of2021-2040s and 2041-2060s,the middle-level and high-level potential distribution areas are mainly distribut in central and southern Kusugul Province,most of Houhangai Province,central Bulgan Province and the junction of the Qianhangai province,Houhangai province and Bayanhonggar province.Among them,the middle-southern Kusugul Province and the junction of the three provinces of Houhangai,Qianhangai,and Bayanhonggar are relatively stable middle-level and high-level potential distribution areas.The high-level potential distribution area is more scattered than under current climatic conditions.The low-level potential distribution area is distributed in a belt shape from the central part of Kobudo Province to the central and western part of the Gobi Altai Province.The distribution area is expanding year by year,and the belt-shaped distribution trend extends to the northwest to the territory of Ubusu Province.This feature can be observed in the three future climate scenarios.(4)The analysis results of the change trend of bio3,bio10 and bio18 under the ssp126 and ssp245 climate scenarios of 2021-2040s and2041-2060s show that in areas where the potential distribution area at all levels increases significantly,bio10 shows an increasing trend,while bio18 shows a decrease trends,regional climate change is consistent with the biological characteristics of Erannis Jacobsoni Djak’s dry biological characteristics.This pattern is not seen in the ssp585 scenario,it can be attributed to the socio-economic development model under this scenario that leads to the highest level of greenhouse gas emissions.