Sand, silt and smooth cord­grass

China Daily (Hong Kong) - - CHINA - By CHEN LIANG

The Shang­hai Chong­ming Dong­tan Na­tional Na­ture Re­serve is one of the few re­serves scat­tered across the Yangtze River basin to have made real progress in the restora­tion of de­gen­er­at­ing wet­land.

Much of the dam­age to the wet­land — formed by the de­posits of mud and sand silt car­ried by the Yangtze River as it drains into the East China Sea — has been caused by a salt­marsh grass that, de­spite its green and soft appearance, is killing the land­scape, according to Tang Chen­dong, the re­serve’s di­rec­tor. Spartina al­terni­flora, com­monly known as smooth cord­grass, is na­tive to the At­lantic coast of the Amer­i­cas, where it is found in in­ter­tidal wet­land. It has be­come no­to­ri­ous as an inva- sive plant around the world be­cause of its ca­pac­ity to ac­cel­er­ate the ac­cu­mu­la­tion of sed­i­ment and cause the level of the land to rise on the seaward edge.

It was in­tro­duced to China in 1979 as an en­vi­ron­men­tal en­gi­neer­ing mea­sure. It was in­tended to catch sed­i­ment and al­low it to ac­cu­mu­late and pre­vent coastal ero­sion.

Since the first plants were dis­cov­ered in Dong­tan in 1995, the grass has spread, and now cov­ers 2,200 hectares of the re­serve’s 241.55 square kilo­me­ters.

“It has led to the loss of habi­tat and re­duc­tion of food re­sources for our ma­jor pro­tec­tion tar­gets — mi­gra­tory wa­ter birds,” Tang told a re­cent meet­ing of the Yangtze Wet­land Pro­tected Area Net­work in Dali, Yun­nan prov­ince.

In 2005, the re­serve’s manag- ers began con­sid­er­ing ways of deal­ing with the plant and started co­op­er­at­ing with uni­ver­si­ties to iden­tify an eco­log­i­cal way of con­trol­ling the spread of the grass and re­claim­ing wet­lands it had al­ready oc­cu­pied. “Oth­er­wise, we would have be­come a re­serve for smooth cord­grass, not birds,” Tang said.

Af­ter sev­eral years of re­search and ex­per­i­ments, the man­agers dis­cov­ered sev­eral ways of deal­ing with the plant, in­clud­ing build­ing lev­ees around ar­eas over­run by the grass to pre­vent it from spread­ing, har­vest­ing the grass, drown­ing the roots, dry­ing the ground in the sun and grow­ing plants, such as reeds and sea­wa­ter rice.

“It took us eight years to re­search and plan the eco­log­i­cal con­trol and restora­tion project be­fore we for­mally launched it in 2012,” Tang said.

With an in­vest­ment of 1 bil­lion yuan ($145 mil­lion) from the Shang­hai mu­nic­i­pal gov­ern­ment, the four-year restora­tion project was launched

I was in tears when I watched the win­ter­ing birds, in­clud­ing var­i­ous types of geese and ducks, re­turn to the area this year.” Tang Chen­dong, di­rec­tor of the Shang­hai Chong­ming Dong­tan Na­tional Na­ture Re­serve

across an area of 25 sq km.

“So far, 99 per­cent of the smooth cord­grass has been swept out of the area and a 15-sq-km area of open wa­ter has been cre­ated, which is ex­cel­lent for the lives of many water­birds,” Tang said. “I was in tears when I watched the win­ter­ing birds, in­clud­ing var­i­ous types of geese and ducks, re­turn to the area this year. That’s the big­gest re­ward for our ef­forts.”

Es­tab­lished in 1998, the re­serve, at the east­ern end of Chong­ming Is­land, is a key stopover site on the East Asian– Aus­tralasian Fly­way. It is im­por­tant for tens of thou­sands of mi­gra­tory waders or shore­birds that breed in North­ern Asia and Alaska and spend the non-breed­ing sea­son in South­east Asia and Aus­trala­sia.

So far, 290 species of birds have been spot­ted at the re­serve, 35 of which are un­der State pro­tec­tion. It is es­ti­mated that ev­ery year about 300,000 mi­gra­tory birds will make a stopover at the re­serve, which in 2002 joined the Con­ven­tion on Wet­land of In­ter­na­tional Im­por­tance Es­pe­cially as Wa­ter­fowl Habi­tat — also known as the Ram­sar Con­ven­tion — and was des­ig­nated World Ra­mar Site No 1144.

YUAN SAIJUN / FOR CHINA DAILY

A flock of tun­dra swans at an eco­log­i­cal restora­tion area in the Shang­hai Chong­ming Dong­tan Na­tional Na­ture Re­serve.

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