Wetland barometer

In 2020, rasse, Eurasian otter and Indian scops owl, three other protected species were also spotted in the Mangrove Ecological Park in Shenzhen city, South China's Guangdong province.

Among the three, the otter as a top predator in the fresh water ecological system is highly sensitive to pollution and damage to its natural habitat, and it is known as the "barometer of wetland quality". Prior to 2020, the Eurasian otter had last been seen in 1998.

And rasse, a first-class species under State protection had never been seen in the urban areas of Shenzhen before.