BEIJING -- Mangrove forests in China have expanded since the start of this century, making the country one of the few to have seen a net increase in mangrove coverage, official data showed on Sunday, World Wetlands Day.

The total area of China's mangrove forests has reached 30,300 hectares, up approximately 8,300 hectares from the beginning of this century, according to the National Forestry and Grassland Administration.

The progress came as a result of China's intensified efforts to protect and restore its mangroves, which are evergreen trees or shrubs that grow in intertidal zones on tropical or subtropical coasts. Sometimes referred to as "coast guards," they play a vital role in purifying seawater, in mitigating the impacts of wind and waves, and in maintaining biodiversity.

Over the past five years, China has planted over 8,800 hectares of mangroves and rehabilitated an additional 8,200 hectares, according to an administration official.

This progress has been part of the country's broader work to protect its wetlands. More than 1 million hectares of wetlands have been created or restored since late 2012, with China's total wetland area remaining stable and now at over 56.35 million hectares. More than 2,200 wetland nature reserves have been established nationwide, and major wetlands have seen notable ecological improvements.

Over the last two decades, China has established 903 national wetland parks, which collectively protect 2.4 million hectares of wetlands and are mostly open to the public and free to enter.

To strengthen wetland conservation, the administration will implement China's law on wetland protection in full, enhance its monitoring and supervision work, advance mangrove conservation and invasive plant control initiatives, and support the construction and operations of an international mangrove center, the official said.