CHENGDU — Whenever a strong earthquake hits Southwest China's Sichuan province, panda lovers across the world feel their hearts tighten.

A 7.0-magnitude earthquake hit Jiuzhaigou County, a popular tourist area, at 9:19 pm Tuesday at a depth of 20 km.

The China Conservation and Research Center for the Giant Panda (CCRCGP) quickly confirmed that pandas and staff at its base, 400 km from the quake epicenter, were not affected by the earthquake.

Preliminary checks confirmed that no pandas were injured and their breeding houses in the center's several reserves remained intact.

However, the earthquake was near a panda migration corridor and might have an impact on the wild population in the area, according to Gu Xiaodong, deputy director of a local wildlife protection station.

Giant pandas live mainly in the mountains of Sichuan and neighboring Shaanxi and Gansu provinces. Due to habitat loss and very low birthrates, only about 1,800 still live in the wild, while some 300 live in captivity.

Panda reserves cover about 60 percent of their natural habitat and are home to 70 percent of wild population. Most of the habitat is in Sichuan, where earthquakes and habitat fragmentation have affected panda breeding patterns.

Secondary disasters, such as screes and barrier lakes, also change the habitat, cut off food sources and increase risks for the wild population.

On May 12, 2008, an 8.0-magnitude earthquake damaged Sichuan's Wolong Panda Reserve. Most of its pandas and staff were transferred to another facility in Ya'an, 140 kilometers from provincial capital Chengdu.

That facility fell victim to similar circumstances when a 7.0-magnitude earthquake hit Lushan County on April 20, 2013. The center reported minimal damage and all 61 of its pandas were uninjured.

A new panda breeding and research center, sponsored by the government of Hong Kong Special Administrative Region (SAR), has been built on less rugged terrain in the Wolong reserve, with the capacity to accommodate 80 captive pandas.

Two years after the earthquake, Wolong restarted its program training captive-bred pandas to live in the wild.

Gu said after the 2008 quake a giant panda rescue plan was introduced. Local residents are required to report sightings of injured pandas to a wild animal protection center, who will send veterinarians and center staff to check the panda's condition.

Local forestry authorities also take measures to restore panda habitat after earthquakes.

In 2016, the provincial government put forward a plan for a giant panda national park that would unite the isolated habitats.

The park, which will cover 27,134 square kilometers, aims to restore migration corridors to link 67 panda reserves on six isolated mountain ranges. It will allow wild pandas to mate with pandas from other areas to enrich their gene pool and raise their numbers in the wild.