Wild Shanghai EP7: Houtan Wetland – a natural habitat for wildlife in downtown Shanghai
Shot by Hu Jun, Liu Jieyun, Zhou Shengjie, Dai Qian and Yan Jingyang. Edited by Hu Jun.
Houtan Wetland is situated adjacent to the Huangpu River, on a site that was once a desolate industrial plain. Following the World Expo 2010 in Shanghai, the region was transformed into a man-made oasis. Since then, Houtan Wetland has been a valuable provider of ecosystem services, such as water cleansing, a serene place for nearby residents to relax in nature, and a natural habitat for urban wildlife.
Water purification
Water purification was a critical objective of the wetland's design. While, the wetland receives Lower Grade V (the poorest grade) water from the Huangpu River, various methods were utilized to treat the water, including the natural purification function of a wetland.
As water flows through, suspended particles settle and nutrients are absorbed by the aquatic plants. Local fish, invertebrates, and other benthic species were also introduced to create a complete ecosystem and improve the purification function. The wetland also provides a perfect habitat for birds and other urban wildlife to thrive.
Ecological riverbank
Many riverbanks in Shanghai are characterized by straight concrete walls that are easy to maintain and assist in flood control. However, these designs are unfavorable for local plants and wildlife. Houtan Wetland employs uneven edges of large stones which enable native species to grow alongside and provide an ideal habitat. It is a unique place where visitors can witness the natural tides of the Huangpu River in downtown area. During low tide, one can observe crabs and mudskippers living in the mudflats.
Mosquito fish
Mosquito fish, as suggested by their name, eat mosquito larvae and have been used for mosquito control. However, they have a diverse diet, and mosquitoes are only a small part of what they eat. Originally a North American species, they have been introduced to many parts of the world, causing ecological issues.
When introduced, invasive species can occupy the ecological niche of native species that also control mosquito larvae. Mosquito fish are competitive and will even consume local aquatic creatures such as fish and frogs. Therefore, they are not effectively controlling the mosquito population as expected.
Red-billed Starling
The red-billed staring is well named with its obvious red bill, making it easy to identify in the wild. Like other starling species, they are clever birds and highly adaptive. They like to forage in a group, especially in the winter.
In China, they have gained the nickname of "cow shit starling" as people often see them active around cow manure. The reason is that the manure contains a large amount of insects, which are a good food resource for the starlings.
Chinese mitten crab
The Chinese mitten crab is a native crab species of East Asia found in rivers, estuaries, and coastal habitats. Its range extends from Korea in the north to Fujian Province in southeastern China. The species is migratory and primarily resides in freshwater, but must return to the sea for breeding. Its larvae develop in estuaries, and the juvenile crabs move upstream later. The Chinese mitten crab is a well-liked delicacy in China, especially those cultivated in Yangcheng Lake in Suzhou of Jiangsu Province.
