Study on the Natural Regeneration of Mangrove Species Sonneratia caseolaris

Sonneratia caseolaris is one of the mangrove species distributed originally in Hainan Island. It was introduced to Shenzhen Bay in 1994, and regeneration appeared in 1999 The research showed that there appeared seedlings within both sonneratia caseolaris plantation and natural mangrove forests, and on exposed tidal flat as well. Of all the sampling plots, the regeneration frequency was up to 45.0%, the density of seedlings was 69 per square meter at most, and the dispersal distance of seedlings amounted to 90 meters at least. Plenty of seeds and warm climate were the premise of regeneration of sonneratia caseolaris, and the temperature of winter was the key factor to determine the success of regeneration. The concrete settlement sites and numbers of regenerated seedlings were closely related to the received light, closeness of sites where seeds were dispersed, deepness of tidal water, tidal hydrodynamics, human activities, feeding activities of water birds and edge effect as well. The number of the regenerated seedlings at the settlement sites became less as the distance to the sonneratia caseolaris plantation (seed producing sites) became increased, and the former and the latter accorded with the relation model: y=y=58.866-25.741 log101.717x.