Environmental remediation promotes the restoration of biodiversity in the Shenzhen Bay Estuary, South China

Abstract

Rapid urbanization has greatly changed land-use patterns in many estuarine areas around the world, including the Guangdong–Hong Kong–Macao Greater Bay Area (GBA). In GBA, this has resulted in serious water pollution and ecosystem degradation. To control water pollution and to restore the integrity and health of the estuary ecosystem, Shenzhen City has conducted comprehensive ecological management and restoration in Shenzhen Bay since 2007. During the restoration, the natural vegetation consisting of mangroves, semi-mangroves, wetland plants, and terrestrial plants was restored from the bund to the inner bank of the Fengtang River, which flows into the bay. Rain and sewage flow diversion systems were established. The non-point source and point-source sewage are now treated in municipal sewage treatment plants, and the treated water naturally flows through the constructed wetland, and then through a natural wetland, restored natural embankment, and finally through mangrove communities; this step-wise flow substantially improves water quality. The restoration of habitats and the reintroduction of indigenous plants has increased animal and microbial diversity and has supported the establishment of a complex and stable food web. With water purification and habitat restoration, the number of alien invasive plants in the estuarine ecosystem has decreased, and the diversity of native species of birds, fish, macrobenthos, amphibians, and reptiles has increased. These improvements indicate that human beings and nature can coexist in support of the sustainable development of Shenzhen City.

Keywords

• coastal city
• sewage treatment
• ecological restoration
• mangrove
• bird diversity