| The Asian elephant(Elephas maximus L.)is a rare and endangered wild animal with global conservation significance.It is listed as an endangered species by the International Union for Natural and Natural Resources Conservation(IUCN).Currently wild Asian elephants are distributing just in a few areas in Xishuangbanna,Pu'er and Lancang,Yunnan,China,and facing severe survival challenges.The proposed Menghai-Menglian Expressway is an important interconnecting link between Menghai County(in Xishuangbanna)and Lancang County and Menglian County(in Pu'er).The result of routes comparison showed that,the best route will inevitably cross the distribution area of wild Asian elephants,and bring some potential impacts to Elephants and their habitats.In this paper,the main research areas are 1 km from both sides along the planned Menghai-Menglian Expressway.The field investigation method,the follow-up investigation method,the drone investigation method,the sample line method,the sample method,and other field investigation methods were combined to investigate the distribution,number,population structure,and migration channel of Asian elephants along the proposed highway.We have comprehensively collected information on the vegetation,feeding plants,nitrate and other information of Asian elephant habitats.Based on global positioning system(GPS),geographic information system(GIS)and remote sensing data(RS),we use statistical software such as SPSS to analyze,Then,the suitability of habitats along the route and the potential impact of the project on Asian elephants and habitats are discussed.Based on these results,we have put forward opinions on the design,construction and operation of the proposed high-speed highway,and made relevant suggestions on the protection and management of Asian elephants along the line.The main results and conclusions are summarized as follows:(1)The wild Asian elephants distributed along the planned Menghai to Menglian Expressway migrated from the east bank of the Lancang River in the early stage.The population has grown from 4,when the group was established,to 17 at present,including 3 males and females 8 heads,6 sub-adult elephants.(2)Taking the main habitat factors affecting the distribution of Asian elephants as suitability evaluation parameters,three environmental factors including altitude,slope and vegetation cover were selected.Based on remote sensing(RS)data and basic geographic data,by using ArcGIS software,analysis of single-factor suitability data for Asian elephant habitats along the proposed high-speed,and then,these three environmental factors are superimposed and analyzed to obtain comprehensive suitability data for habitats.Based on the results,the suitability along the line is comprehensively evaluated.The results show that,the area with good suitability only accounts for 1% of the whole section,while the areas with moderate suitability and poor suitability account for 57.8% and 42.2%,respectively.This area is not the most suitable area for Asian elephant survival.(3)Seven plant samples were set up in the Asian elephant activity areas along the route,and a total of 136 plants were recorded,belongs to 41 orders,57 families,and 118 genera,include 40 species of Asian elephant feeding plants,which belongs to 18 genera,24 families and 37 genera,accounting for 29.4% of total plant species.It indicates that the relative abundance of plant resources available for feeding by Asian elephants in this region,it may be the main factor for Asian elephants' activities in the long term in this region.(4)Prediction of Asiatic elephant suitable habitats in Menghai County using MAXENT model,It is found that the area of the proposed high-speed highway in Menghai County that is highly suitable for Asian elephants accounts for only 3%,while the proportion of low-suitable areas,marginal suitable areas,suitable areas and non-suitable areas is 43 %,38%,10%,and 6%.Highly suitable habitats are mainly distributed in Mengman township.It is speculated that this may be the main reason for Asian elephants to go to Mengman town.(5)Using the trace tracking method to trace and draw the local Asian elephant migration route,combined with the project design and planning,we found that there was an intersection of the Asian elephant trajectory and the highway planning route in Mengman Town,Menghai County.The engineering design has been here,a tunnel of 600 m long has been designed here to meet the needs of elephant herds moving across the highway.(6)The determination of the water content in the salt pond showed that there was a certain correlation between the magnesium and salt content and the utilization rate of the Asian elephant in the salt pond.Spatial analysis of road interference by the Asian elephant's use of salt ponds and surface converging water systems revealed that the proposed highway planned route did not directly reduce the number of Asian elephant's use of salt ponds.The disturbed areas of the river system are mainly concentrated in the town of Mengman and the west section.Based on these analysis results above,the direct impact of the construction of the expressway on the local Asian elephant is relatively weak.Based on the results of this survey and analysis,the following suggestions are made for the optimization of project construction and the protection of Asian elephants along the route:(1)Artificially cancel the salt pond affected by the proposed high-speed interference to prevent Asian elephants from going to these areas and causing elephant-vehicle conflicts or human elephant conflicts.(2)To avoid elephant-car conflicts or human-elephant conflicts,On both sides of the passage where the expressway intersects with the Asian elephant's activity track,artificially planted Asian elephants' favorite foods guide them through the tunnel.(3)It is necessary to strengthen the supervision of roads during construction and operation,to ensure the availability of passages and the subsequent monitoring. |
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