不同树龄桐花树茎上白条地藤壶分布特征的研究

Study on the Distribution Characteristic of Euraphia withersi Attached to the Stems of Different-Aged Aegiceras corniculatum

研究了广西英罗港红树林区向海林带不同树龄的桐花树茎上白条地藤壶的分布特征．结果表明：白条地藤壶在茎上的附着高度（ｈ）随树龄和树高增大而增大．在最大树龄 １７龄植株上平均达到 １８２ ｃｍ．此高度为潮高约５１２ｍ海水才能浸及，在一年中约有将近９０％的时间暴露在空气中．耐着高度（ｈ）与树高（Ｈ）比值ｈ／Ｈ以５龄树最大，达９１．９％。树层最大密度达４６６００Ｉｎｄ／ｍ２．最小为１７２Ｉｎｄ／ｍ２。在同一树龄的不同树层，密度表现为先随树高增大逐渐增大，达到最大密度后又下降。在不同树龄的同一树层．密度高低变化，分布一般出现多个峰．白条地藤壶最适宜附着和生长在桐花树茎上１００～１２０ｃｍ树层（浸及此树层的海水潮高约为 ４３０～４５０ｃｍ）．树层最大生物量为 １７１９．０５ｇ／ｍ２，最小为 ５．３９ｇ／ｍ２．生物量分布与密度的相似．

This paper deals with the distribution characteristic of Euraphia withersi attached to the steins of different-aged Aegiceras corniculaum trees on the seaward forest zone of Yingluo Bay mangrove area in Guangxi. The results Show that the attaching heights (h ) go up with the tree ages and the tree height (H). The attaching height of 17-year-old bees (the oldest ones ) reaches 182 cm, which can be immersed in the seawater of about 512 cm tidal height and is exposed in the air over about 90 % of the time of a year. The ratio us of a 5-year-old tree reaches the highest value of 91.9 %. The highest density of bee layers is 46 600 Ind./m2, and the lowest only 172 Ind./ m2. As to the different bee layers of the same tree ages, the densities go up with the tree heights firstly and then descend after the highest density. As to the same tree layers of different tree ages, the densities usually have several peaks. The tree layer of 100-to-120-cm, which can be immersed in the seawater of about 430-to-450-cm tidal height, is the most suitable for the attachment and growth of E. withersi. The highest biomass of the tree layers is 1 719.05 g/m2, and the lowest only 5.39 g/m2. The distribution of biomass is similar to that of density.