Study On The Potential Geographic Distribution Of Bursaphelenchus Xylophilus In China

With the development of the global integration and international exchanging and trading, the invasive alien species dispersal causes a large damage to the ecology system of the country invaded. Pine wood nematode (Bursaphelenchus xylophilus), as an agent of pine wilt disease and the important quarantine target of many countries around the world, has been the most serious invasive pest in China. Using tow methods based on GIS, the potential geographic distribution of Bursaphelenchus xylophilus in China is analysed in this paper.It is impotant for the analysis of the posibility of disease epidemic of Bursaphelenchus xylophilus in the different part of China and the assessment of the risk Bursaphelenchus xylophilus in china.(1)The potential distribution of Bursaphelenchu xylophilus is similar in 5 models.The distribution is mainly between 18°-40°N,including some provinces in the middle and southern part of China.Except ENFA,some low suitable distribution appears in Shanxi,Hebei,Liaoning in other four models,and suitable distribution appears in Liaoning of DOMAIN analysis.(2)There are two parts of optimal suitable distribution in 5 models.The first area is the Middle and Lower Yangtze regions with gently rolling topography ,good tempreture and humidity suitable to Bursaphelenchu xylophilus .The other area is mainly in Guangdong, Guangxi and Fujian with low altitude, good tempreture and humidity.These tow parts are really serious pine wood nematode epidemic area. Guangxi,Henan nnd Sichuan should be the quarantine focus to prevent the invading of Bursaphelenchu xylophilus ,because they are optimal suitable distribution and not reported.(3)The suitable rank of the area between Jianxi and Fujian is lower than nearby area and they are marginal and low suitable distribution in 5 models.This area is the marginal zone of the Wuyi mountain with high elevation.The result shows the 5 models analysis are sensitive to the topography.(4)The AUC values of 5models are all better than the random models.Except the significant differences between ENFA and BIOCLIM, there are no significant differences between others.The AUC values of ENFA the biggest in five models.This shows that the analysis result of ENFA is bettee than the other four models.(5)In this paper ENFA,MAXENT and GARP can give us reasonable potential geographic distribution of Bursaphelenchus xylophilus in China.The result of ENFA and MAXENT can be the study on core distribution area and the result of GARP can be the ege of the distribution;the area of BIOCLIM anlysis is relatively big. The accuracy, interpretability and applicability of ENFA和MAXENT are better than GARP,DOMAIN,BIOCLIM.(6)Through the analysis of the 739 Climatic sites, there are 243 suitablest sites, 63 suitabler sites,72suitable sites,116unsuitable sites and 245 unsuitablest sites for Bursaphelenchu xylophilus.The figure of Suitable distribution of Bursphelenchus xylophilus in China shows that the suitable sites mainly exit in southern and easten part of China,including the southern Beijing,Tianjing, the southern Hebei, the southern Shanxi, Shandong, Henan, Hubei, Hunan, Jiangsu, Zhejiang, Shanghai, Jiangxi, Anhui, south east Shanxi, Chongqing, Guizhou, Yunnan, Guangxi, Guangdong, Fujiang, Hainan, Xinjiang.(7)Through the analysis of the 739 Climatic sites, there are 98 suitablest sites, 234 suitabler sites,258suitable sites,11unsuitable sites and 139 unsuitablest sites for Monochamus alternatus.The figure of suitable distribution of Monochamus alternatus in China shows that Monochamus alternatus exit in most of China except Xizang,Qinghai,north west of Sichuan,most of Gansu, north west of Hei Long-jiang,north east of Neimeng.And Guangxi, Guangdong, Hainan, Fujiang,southern Jiangxi, southernYunnan are suitablest distribution of Monochamus alternatus.(8)Through calculating the comprehensive suitable value,not tinking host,we get the the potential distribution of Bursaphelenchu xylophilus in China including the southern Beijing,Tianjing, the southern Hebei, the southern Shanxi, Shandong, Henan, Hubei, Hunan, Jiangsu, Zhejiang, Shanghai, Jiangxi, Anhui, south east Shanxi, Chongqing, Guizhou, Yunnan, Guangxi, Guangdong, Fujiang, Hainan, Xinjiang.(9) Considering the host distribution,the potential distribution of Bursaphelenchu xylophilus include southern Beijing,Tianjing, the southern Hebei, the southern Shanxi, Shandong, Henan, Hubei, Hunan, Jiangsu, Zhejiang, Shanghai, Jiangxi, Anhui, south east Shanxi, Chongqing, Guizhou, Yunnan, Guangxi, Guangdong, Fujiang, Hainan, part of Xinjiang.Most of Yunnan is the potential distribution of Bursaphelenchus xylophilus.(10) The operation of niche modles are simple but the little considering factors and single algorithm make the limitation of the results.The analysis of the fuzzy mathematics need a lot of parameters setting and data calculation which is complex.The area of the potential distribution of Bursaphelenchu xylophilus in the fuzzy mathematics analysis is larger than that in niche modles analysis.