The mangrove forest in the Dongzhai Port Nature Reserve is the typical representative of Hainan Island. The research work of the mangrove forests is of significant importance in protecting the ecological balance of the harbours and the coast lines. The common birds are wild ducks, egrets, sanpipers etc. and there are also plenty of fishes, prawns, crustaceans and molluses.
Full screen map of Dongzhai Port Nature Reserve (On tentative list - China)
I visited the Mangroves during my Christmas holiday 2015 in China. Are they nice? Yes they are. Should it be a UNESCO WHS? Maybe, I think it's a unique place on Hainan Island. If UNESCO or not it should be protected. To be honest I don't see it so quickly becoming a WHS. On the link you find some photos.