| Objective1 Establish Mongolian gerbil green area suitable space prediction model, suggesting that our Mongolian gerbil plague natural foci of distribution space.2 To explore a variety of environmental factors on the distribution of Mongolian gerbils, which found that the optimum environmental elements Mongolian gerbil survive.Methods1 Through national plague reporting system and site surveys Mongolian gerbil point of presence data, and using ArcGIS spatial analysis of data space and to gather processing.2 Environment variable data through the Internet Web site, the use of statistical analysis software SPSS for analysis, the removal of strong relevance environment variables, environment variables remaining biologically significant and relatively independent.3 Maxent ecological niche models use software, build Mongolian gerbil model suitable area analysis Mongolian gerbil suitable areas of major habitat features, and then predict the environmental features of this area where the country.4 prediction model results:the model was evaluated by ROC curve.5 In predicting the results of the investigation on the basis of design solutions, through on-site investigation to verify the model evaluation and analysis.Results1 Mongolian gerbil point of presence data:Mongolian gerbils collected data totaling 1985 points of presence, through ArcGIS software space and the removal of aggregation, the actual point of presence have 1247 data for modeling analysis.2 Environment variable data:the removal of variable correlation coefficient greater than 0.9, and finally to extract biologically meaningful and relatively independent variable 15 environment variables:Biol average annual temperature, Bio4 seasonal temperature changes, Bio5 average temperature of the warmest month, the coldest Bio6 monthly average temperature, Bio9 driest season average temperatures, Biol1 average temperature of the coldest season, Bio 14 driest month of precipitation, seasonal variation Bio 15 precipitation, Bio 16 wettest season precipitation, Bio 17 driest season precipitation, Bio 19 coldest season precipitation amount, DEM altitude, Globcover mulch plant type, Slope slope, Ndvi normalized difference vegetation index.3 Field survey results:total playing Mongolian gerbils 52 plots, of which 28 catches Mongolian gerbil,24 not caught Mongolian gerbil.4 Mongolian gerbil suitable habitat analysis:Mongolian gerbils live between 900m-1600m above sea level; the main types of land cover plants in farmland, vegetation, grass, bare ground mainly to the number of bare majority; normalized difference vegetation index 0.24 to 0.4, a medium low coverage; with the increase of slope and showed a decreasing trend; the average annual temperature between 2.2 ℃-5.4 ℃; annual precipitation between 150mm-359.5mm; mean monthly temperature range between 11.4℃-12 ℃; according to the warmest month average temperature higher than 20 ℃ and the coldest month is less than 0 ℃, and long winter, cold, summer is characterized by periods of major precipitation, Mongolian gerbil living environment The climate is dry and cold winter and warm weather type.5 Model Evaluation Results:The model validation program sensitivity 92.86%, specificity of 100%, overall accuracy of 96%, positive predictive value of 100% and a negative predictive value of 92.3%, kappa coefficient was 0.92 greater than 0.75 description has been made quite satisfied with the degree of consistency, Youden index was 0.93, indicating good diagnostic. Area under the ROC curve 0.684, P= 0.023 showed moderate diagnostic value, statistically significant.6 Modeling results:(1) the model and the importance of the contribution of the strongest variable is bio 16 wettest season precipitation, bio4 seasonal temperature changes, biol年均温. (2) ROC AUC value of 0.962 graph shows, more than 0.9, indicating a higher capacity model discrimination and goodness of fit. (3) from the prediction map can be analyzed, Mongolian gerbil suitable areas are mainly located in Xilin Gol League, Wulanchabu, Alxa League, Datong, Hohhot, Baotou, Bayannaoer, Ordos City Wuhai; Shizuishan Ningxia Hui Autonomous Region, Yinchuan, Wuzhong City, Zhongwei; Baiyin City in Gansu, Wuwei, Zhangye City; Zhangjiakou City, Hebei; Yulin City of Shaanxi Province. The total area of approximately 964,205.5 square kilometers. Forecast for Mongolian gerbils survive, but did not involve the actual monitoring area has Xianghuang, Zhengxiangbaiqi, Chahar right-wing flag, Dalateqi, Wuyuan County, these areas need actual work further verification.DiscussionIn this study, remote sensing technology (RS), Global Positioning System (GPS) and geographic information systems (GIS) combining Maxent ecological niche models for technical support, Inner Mongolian gerbil plague natural foci of the study area modeling, final predicted a nationwide distribution of Mongolian gerbil suitable raw area map, revealing the Mongolian gerbil suitable living environment at an altitude of 900m-1600m mountain and plateau between hi ranking sandy soil, hot summers and cold, dry winter area. Key Tacha data through on-site evaluation of the model, indicating that this model is suitable for Mongolian gerbils predict suitable distribution area, and based on the predicted Mongolian gerbil suitable areas of high and low risk, showing concern region, early warning plague spread risk is significant. |
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