Beimen Lagoon is located in between Wang Ye Gang Shan and the land. Black mangrove once grew massively in the wetland of Beimen Lagoon in the western Beiman E-Liao, the area of which is afterwards explored as polder or fish farms. After the restoration of mangrove, the riverbed of river mouth has 6 hectares of black mangrove. Black mangrove starts to propagate in the Beimen Lagoon at Jishuei River mouth and kandelia candel is introduced and plant. The mangrove reservation is sited in these two areas with notice boards indicating conservation measures.