红树植物海桑天然更新的初步研究

海桑自1994年引种到深圳湾,1999年出现天然更新,在海桑林、天然林和裸滩上均有分布,更新频度达45 0%,幼苗密度最多达69株·m-2,幼苗的扩散距离至少达90m。充足的种源和温暖的气候条件是海桑出现天然更新的前提条件,冬季的低温是决定海桑更新能否成功的关键因素。海桑更新的状况与所接受的光照、种子散播地的隐蔽程度、潮水淹浸深度、潮汐动力作用、人为活动的影响、水禽的取食活动及边缘效应等存在相关关系。海桑幼苗扩散的数量随着距人工海桑林距离的增加而减少,二者符合相关模型:y=58 866 25 741log101 717x。

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.