Distribution variation of Littoraia melanostoma Gray(Littorinidae) in rehabilitated Kandelia candel and Aegiceras corniculatum mangroves with different ages
【摘要】：Seasonal surveys were conducted from April 2005 to January 2006 to compare the distribution of Littoraia melanostoma, a dominant snail species, in rehabilitated Kandelia candel and Aegiceras corniculatum mangroves with different age(4-year, 7-year and mature) in Jiulongjiang Estuary, China. Density of L. melanostoma ranged from 8.3 to 54 ind m-2 in these mangrove, with its biomass ranging from 3.13 to 23.00 g m-2. Repeat measure two-way ANOVAs results showed that L. melanostoma density was higher in A. corniculatum than K. candel forest, and the descending order among mangrove ages was 7-year 4-year mature forest. Significantly higher L. melanostoma density was recorded in A. corniculatum forest than in K. candel forest with the same age. However, greater percentages of middle(shell length15~20 mm)- to large(20 mm)-size snails were found in K.candel and mature A. corniculatum forests compared to the two younger A. corniculatum forests which were dominated by small-size snails(15 mm), indicating different population composition among different mangrove forests. This distribution pattern may be partly attributed to the morphological difference in vegetation. Younger mangrove plants, especially the dense and tufts A. corniculatum plants, are short with dense canopy, and have a higher density of twigs, therefore could support more L. melanostoma individuals and protect them from environmental stresses and predators.