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Environment
ChinaScience

Damage to China’s wetlands by invasive cordgrass highlights fight against biodiversity loss

  • As Kunming hosts COP15 conference, new paper shows how much cordgrass has harmed protected coastal areas since being introduced in 1979
  • Striking ‘red beach’ landscape, native flora and shorebird habitats threatened by exotic species

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A single invasive plant, Spartina alterniflora, has transformed expansive protected wetlands into a “green desert” avoided by waterbirds. Photo: EurekAlert
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Invasion by exotic cordgrass has hampered the conservation of native wetlands in China’s major protected coastal areas, an international team led by Fudan University’s coastal ecology lab found after analysing three decades of data.

They found that cordgrass had invaded four out of seven of the largest coastal wetland protected areas in the country. All are along the Yellow Sea coastline in northeastern China and have been established for at least 20 years.

In the Shanghai Jiuduansha Wetland National Nature Reserve, for example, the area of cordgrass grew from 2.33 sq km (0.85 sq miles) in 2000 to 55.7 sq km (21.5 sq miles) in 2018 after being introduced in 1997.

Cordgrass is native to North America and was introduced to China’s coastlines in 1979 to help prevent erosion and stabilise shorelines because of its tolerance for fluctuating water depth and salinity.

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But in 2003, China listed it as an invasive alien species, noting that it “threatened native coastal ecosystems and caused large areas of mangroves to disappear”.

The researchers said controlling the invasion of exotic species and restoring native species were needed to avoid large-scale, long-term dysfunction of protected zones. Establishing these zones is a key biodiversity target in the coming decade.

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They also advised against bringing in highly invasive foreign species in the future for local plants and animal habitats to be protected.

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