Fifteen wild Asian elephants that left their habitat in Xishuangbanna National Nature Reserve in Yunnan province have so far not caused any trouble in the provincial capital, Kunming, thanks to local authorities' contingency measures.

By Thursday afternoon, the herd had moved to Shuanghe county, Jinning district in Kunming's outskirts, according to the Yunnan Forestry and Grassland Administration, which has established a special work team under the guidance of the provincial government.

Provincial forestry police have followed the elephants' movements round the clock using drones and cameras. Experts from both the national and provincial forestry departments are advising on measures to control the elephants.

Police and firefighters in Kunming are working to prevent the elephants from coming into contact with residents. Trucks and digging equipment have been put in place at the entrances of villages to try to stop the pachyderms' entry.

A woman surnamed Li who is from Ganhe village, Shuanghe, where the elephants lingered for several hours on Thursday, told local media that they had received alerts from the village committee. "All my family members moved to the second floor of our house on Wednesday. We were very nervous last night, but luckily no one was hurt," she said.

Forest police in neighboring Yuxi, where the herd was on Wednesday, said the city is still on high alert for the possible return of the elephants.

Although it's not known when the herd left the Xishuangbanna reserve, experts believe they may have started roaming last year and are now approximately 500 kilometers from their home habitat.

The Asian elephant, which is listed as endangered on the International Union for Conservation of Nature Red List of Threatened Species, enjoys Class-A protection status in China, the same level afforded the giant panda.

Yunnan is the sole habitat of wild Asian elephants in China and has 300 of the animals.

However, more than two-thirds of the population live outside nature reserves, said Chen Mingyong, a life sciences professor at Yunnan University who has been studying wild elephants for decades.

Although the reason for the herd's march north is not known, experts believe that wild elephants migrate from their natural habitat mainly due to a lack of food.

"Forest coverage has surged in recent decades in south Yunnan and areas of forests used for economic purposes by farmers have also expanded," said Wang Hongxin, head of the Academy for Global Development at Beijing Normal University. "Both have resulted in declines in the supplies of the elephants' favorite foods, such as plume grass. A well-protected forest is not the most favorable habitat for elephants."

Last year, Wang and his team visited Yunnan twice to conduct research into the living conditions of Asian elephants in the wild. Wang said the combination of limited food sources and isolated habitats has driven the elephants from the Xishuangbanna reserve and smaller ones to nearby villages and farms.

Since 2008, the reserve has built a "canteen" for wild animals, mainly elephants, providing them with bamboo, corn, plantain and sugar cane. A year later, another feeding center was built in Pu'er, a city north of Xishuangbanna, which is also an elephant habitat.

"These canteens provide elephants with additional food. But on the other hand, the 'delicious' food, together with corn and other agriculture products on farmland, make the elephants even harder to be sated by 'wild food'," Wang said.

Building a national park for the elephants as soon as possible would help solve the problem, he said. Xishuangbanna reserve is expected to remap the elephants' habitat with an improved classification system, which will limit human activities in the core protected area.

A scientific plan should also be implemented at the park to diversify wild plants species, while alert systems should be set up in major habitats and shared on an open platform to monitor the elephants' movements.

The rights and responsibilities on managing elephant protection should also be clearly stated, Wang said. "Although the wild elephants only live in Yunnan, it is a State-protected animal and should gain more financial support from the central government," he said.

Another herd of 17 wild Asian elephants in Yunnan recently broke into the Xishuangbanna Tropical Botanical Garden, a research institution under the Chinese Academy of Sciences and one of the biggest botanic gardens in the country. The garden is renowned for its diversity of species, with 13,000 varieties of wild plants, of which 1,350 are endangered.

On Thursday, the herd moved to the eastern part of the garden where seeds are bred and developed and plants with important research value are kept.

The herd tried to cross the river surrounding the garden, but failed due to quickly rising water levels caused by heavy rain. "Some of the plants have been destroyed," garden management said in an announcement released on Thursday. "We've asked for help from elephant experts on how to guide the herd from the garden."