The South China Karst World Heritage Site and the Mammoth Cave National Park in the United States signed a sister park arrangement on Monday, marking a start of their environmental cooperation.

The fourth of its kind, the relationship would serve as a platform for the two sites' communication, and set up a framework for their cooperation, said Li Rusheng, deputy director-general of the Urban Development Department of China's Ministry of Housing and Urban-Rural Development.

China actively pursues a road of sustainable development, while the United States has advantages of scientific research, science popularization and management, said Li, noting the two countries would see broad prospects in environmental cooperation.

Li said the two sites would launch cooperation in fields such as management, technology and professional knowledge, and conduct exchange visits to each other.

To begin with, the two sides could cooperate on the translation of the scenic areas' Web sites and their introductions, in an effort to facilitate tourism, said Pat Reed, director of the Mammoth Cave National park.

Reed, who attended the signing ceremony wearing his green park keeper uniform, said his recent visit to Yunnan's Shilin impressed him much. The scenery there was very "beautiful," he said.

Renowned for the karst topography, the South China Karst World Heritage site consists of three sub-areas: Libo in Guizhou Province, Shilin in Yunnan Province and Wulong in Chongqing Municipality. And the Mammoth Cave National park has the longest known cave system in the world.

China's Ministry of Housing and Urban-Rural Development inked a memorandum of understanding with the National Park Service of U.S. Department of the Interior in 1998, and set up a cooperative mechanism between the parks of the two countries.

The first sister-park relationship was forged between Mount Huangshan in East China's Anhui Province and the U.S. Yosemite National Park in 2006.