title: Asian elephants in China: estimating population size and evaluating habitat suitability.
abstract: We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu'Er) carried mtDNA from the α clade, and only one population (Nangunhe) carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure their natural habitats are critical for the survival of Asian elephants in this region.
authors.affiliation: Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Dong
authors.affiliation: College of Life Sciences, Hainan Normal University, Haikou, 571158, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Lin
authors.affiliation: Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Feng
authors.affiliation: Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Yan
authors.affiliation: Research Institute of Xishuangbanna National Nature Reserve, Jinghong, 666100, China.
authors.forename: Lanxin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Research Institute of Xishuangbanna National Nature Reserve, Jinghong, 666100, China.
authors.forename: Xianming
authors.initials: X
authors.lastname: Guo
authors.affiliation: Research Institute of Xishuangbanna National Nature Reserve, Jinghong, 666100, China.
authors.forename: Aidong
authors.initials: A
authors.lastname: Luo
mesh_terms: D000818:Animals; D002681:China; D017753:Ecosystem; D004606:Elephants; D011156:Population Density