Abstract: Hainan Dongzhai Harbor National Nature Reserve has a main base for introduction and domestication of exotic mangrove species in China, among which Sonneratia apetala and Laguncularia racemosa were introduced from Bangladesh in 1985 and from Mexico in 1999 respectively. After that, those species were introduced from the base to other wetlands in China. Currently, they have formed adult forests in many coastal wetlands in Hainan Island and Southern China, which caused concern about their possible adverse impacts on indigenous mangrove plant communities. In this study, we surveyed the artificial plantation and natural spread of S. apetala andL. racemosa in Dongzhai Harbor Nature Reserve in July 2019, and analyzed their spread routes and trends to offer a reference for the management of exotic species in mangrove wetlands. The results showed that artificial plantation of S. apetala was 40.56 hm², mainly distributed in the outer buffer and core zone, and the area of natural spread was 40.12 hm², most of which were scattered in the core zone and buffer zone. It is difficult to identify the spread route due to different planting times and decentralized planting sites. The artificial planting area of L. racemosawas 6.23 hm², mainly distributed in protected water and outer buffer zone, while the spread area was 0.53 hm², mainly in the buffer zone. Three main spread areas of L. racemosawere located around the relatively concentrated planting area, which could be identified that the individuals spread radially from planting areas to the areas as far as 3-5 km in straightline distance. Due to large density of seedlings in spread areas, there is an outbreak trend of L. racemosa. Those two exotic species spread into the indigenous mangrove communities and form mixed communities. Whether the exotic species will adversely affect native mangrove communities in the future remains to be clarified.

Key words: fecundity, pomegranate variety,