无瓣海桑、海桑、秋茄红树人工林群落动态及物种多样性研究

对红树植物无瓣海桑、海桑、秋茄3种人工林群落动态及物种多样性特征的系统研究结果表明，无瓣海桑群落和海桑群落的乔木层明显分为上层和中层两个亚层，上层木为无瓣海桑或海桑，中层木主要为秋茄和桐花树；秋茄群落的乔木层为单一层次，基本由秋茄组成．在无瓣海桑群落和海桑群落中，优势种群无瓣海桑或海桑仅有高龄级个体存在，未出现自然更新现象；秋茄和桐花树为旺盛增长种群，有可能成为优势种群，表明无瓣海桑和海桑为先锋造林树种，在裸滩种植可以促进其它红树植物的天然定居生长；在秋茄群落中，秋茄为旺盛增长种群，能够自然：更新演替，桐花树和海莲属初生增长种群．无瓣海桑群落和海桑群落的物种组成和物种多样性指标较接近，基本包含秋茄群落中的主要物种秋茄、桐花和海莲。表明无瓣海桑和海桑能与这些物种协调共生，同时种植无瓣海桑或海桑可以形成多样化的红树林群落；无瓣海桑群落和海桑群落在形成初期，种植密度较大时，物种多样性较高；密度相近时。形成初期随林龄的增加。其物种多样性略有提高．

Dynamics and species-diversities of artificial Sonneratia apetala,Sonneratia caseolaris and Kandelia candel communities

Studies on the dynamics and species diversities of artificial Sonneratia apetala,Sonneratia caseolaris and Kandelia candel communities showed that the arbor layer of S.apetala and S.caseolaris communities contained two distinctive sub layers.The upper layer was composed of S.apetala or S.caseolaris ,and the medium layer was composed of K.candel and Aegiceras corniculatum .The dominant population S.apetala or S.caseolaris in S.apetala and S.caseolaris communities only had old aged individuals but no regenerations appeared recently,while K.candel and A.corniculatum were actively progressive populations,which would possibly become dominant populations during the course of community development,showing that S.apetala and S.caseolaris were pioneer species for plantation,which could promote natural colonization of regional mangrove species when planted at open mudflat. K.candel was the actively progressive population in K.candel community,its natural regeneration and succession could be successful,while A.corniculatum and B.sexangula were initially progressive populations.The species composition and species diversities of S.apetala and S.caseolaris communities were similar,both contained the main species in K.candel community,namely, K.candel,A.corniculatum and Bruguiera sexangula ,showing that S.apetala and S.caseolaris could co exist with these regional species.To introduce and plant them could help to form complicated and diversified mangrove communities.During the early stage of the development,the species diversities of S.apetala and S.caseolaris communities were higher when their planting density was high.The species diversities grew slightly higher when the communities became older.