This study focused primarily on the population and habitat status of Asian elephants in Mengla Sub-reserve of Xishuangbanna National Nature Reserve in the Yunnan Province of China. Data was collected on the number of elephants, their range and human-elephant conflict through local interviews, community monitoring network and field survey during two time periods-the first period was from July 2006 to October 2007 and the second period was from August 2008 to August 2009. Trace-tracking was also used to collect data on major elephant moving lines during the first period. Ecological Niche Factor Analysis (ENFA) with 3S technique was the method used to evaluate habitat quality and predict suitable habitat for Asian elephants.
Results showed that 25-32 wild elephants inhabited the Mengla sub-reserve in 2007, with that number increasing to 35-42 in 2009. Their range included the southeastern and eastern parts of the reserve covering an area of 221 km² during 2006-2007, representing 19.2% of the total reserve. Wild elephants developed fixed moving routes to facilitate foraging of natural plants and cultivated crops. The total length of moving lines was 65 km, and resulted in human-elephant conflict in 14 villages. This included economic loss due to crop-raiding and accidental deaths by trampling.
Based on ENFA, elephants in Mengla showed preference for lower elevations (<999 m) and milder gradients (<8°), including tropical bamboo forest and scrub-grassland, as well as areas with lower human disturbance. The preferred habitat for Asian elephants, including marginal, suitable and optimal habitat, covered a total area of 328.5 km², representing 28.5% of the total reserve and was mainly divided into two patches-patch one in the southeast and patch two in the northwest part of Mengla sub-reserve covering an area of 150.5 km² and 178 km² respectively. However, elephants were found only in a portion of patch one during the first study period. In the elephant range, the preferred habitat represented 52.9% of the range, while the remainder consisted of farmland, rubber & tea plantations and steep mountains. The findings of the study urge conservation measures including anti-deforestation, anti-poaching, ecological corridor building, human-elephant conflict mitigation and trans-boundary cooperation to protect the Asian elephants.