Researchers and local governments in the Yellow River Delta have designed tailor-made techniques for restoring wetland by removing cordgrass, an invasive species, to prepare for the establishment of a national park in Shandong province.

Spartina alterniflora, more commonly known as smooth cordgrass, is an invasive species to China. It was first introduced from the Atlantic coast of the United States to shore up earthen dams, according to Xie Baohua, an associate researcher at the Yantai Institute of Coastal Zone Research at the Chinese Academy of Sciences.

He said that from 2010 to 2020, the area of cordgrass multiplied by 25 percent on average every year in the delta.

"Cordgrass stretching tens of kilometers across low water flats created a dam, blocking intertidal water, creating temperature differences and harming the coastal wetland ecology. Birds were not seen in tall grass areas before treatment because they couldn't rest there," Xie said.

Since 2020, the marine development and fisheries bureau of Dongying city, which lies in the delta, has begun treating the grass. It cut it down, then plowed and flooded the area to prevent its return.

The Dongying municipal government oversees the delta's nature reserve and by the end of last year, it had eradicated about 10,547 hectares of cordgrass and said that after treatment, the number of bird species nearly doubled from 187 to 371 species.

"The treatment does not mean the grass has been completely eradicated from the delta, so an early warning and monitoring system should be put in place to prevent the plant from reestablishing itself," Xie said.

In June, the Shandong provincial government applied to the National Forestry and Grassland Administration to establish the Yellow River Estuary National Park to protect the fragile delta environment.

The province has completed preparatory work and will start the project soon.

According to the management committee of the reserve, 3,518 square kilometers have been designated for the national park.

The reserve is a breeding ground for oriental white storks and black-billed gulls.

To prepare for the establishment of the park, the reserve has allowed thousands of hectares of farmland to revert to wetlands and beaches.

China is in the process of creating its national park system, which will eventually cover about 10 percent of the country's surface area.