Ecologists seek urgent action to protect city's vital wetland

The original ecology of the Jiuduansha Wetland, the city's last virgin land, is degenerating in some areas though the environment is relatively better maintained than other wetlands, according to the latest research.

Ecologists are calling for protective measures to be taken before the degenerating trend becomes irreversible.

Yang Yongxing, a professor in environment science from the Tongji University, has visited the wetland, an island located at the mouth of the Yangtze River, 13 times since he began his research four years ago.

The 420-square-kilometer wetland has been in existence for just 50 years. It functions to store floodwater and prevent drought, adjust the climate and control pollution for the city.

Researchers found the biggest threat to the wetland came from intrusion of exotic species.

A plant from the United States, smooth cordgrass, was grown on the middle part of the wetland a few years ago to distract birds from Pudong International Airport. But the plant started to take the place of a native species, scripus mariquter, a major food source for water birds.

Now the plant has covered the middle and lower parts of Jiuduansha and began to erode the upper part. It expanded so fast that it occupied more than 200 square meters of land that used to be occupied by native plants in just eight months, Yang's group observed.

In addition, the pollution of the Yangtze River water was also affecting water quality on the island, Yang said. Water in some areas contained an excessive amount of pollutants, while a healthy wetland should have good self-cleaning function.

"The wetland, serving as a highly efficient natural plant for polluted water treatment, will be unable to bear the heavy burden if the Yangtze River's water quality continues to deteriorate," Yang said.

He said that the increasing presence of fishermen, who chose the island as a shelter from high winds, was also destroying the wetland environment.

"The global wetland area has shrunk by 80 percent in the last 100 years, and many existing wetlands are also in degeneration.

"The best way to protect wetland is to prevent it from getting 'sick' instead of trying to treat it," Yang said.

TAG: seek to ecologists urgent action protect vital wetland