Asian elephants in China: estimating population size and evaluating habitat suitability.

Li Zhang,Xianming Guo,Liu Lin,Lanxin Wang,Limin Feng,Lu Dong,Aidong Luo,Fan Yan,Zhigang Jiang

doi:10.1371/journal.pone.0124834

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.

Highlights

The Asian elephant (Elephas maximus) is the largest terrestrial animal in Asia
An earlier report estimated that the Chinese elephant population size was approximately 150 in 1976 [2]
We investigated the Asian elephant population and their habitat status in China via a decade-long monitoring program, enabling a comprehensive conservation strategy to be developed in order to secure the survival of this endangered species in China

Summary

Introduction

The Asian elephant (Elephas maximus) is the largest terrestrial animal in Asia. It occurs in Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Sir Lanka, Thailand, and Vietnam. The estimated population size of wild Asian elephants in China was approximately 200 [3]. Habitat selection by Asian elephants had been studied in China and many other regions in Asia over the past three decades [5,6,7,8,9,10,11,12].

Results

Conclusion