红树林恢复初期莱氏锥滨螺分布动态

树栖腹足类动物是红树林底栖动物的重要组成部分，其组成和分布受到红树植被的影响。因此，在红树林生态修复中，腹足类动物的恢复依赖于植被的发育。滨螺科(Littorinidae)锥滨螺属(Mainwaringia)动物是亚洲红树林的广布种，但针对其在红树林中的分布及种群特征的研究较少，对红树林植被恢复过程中锥滨螺属动物的恢复动态更是鲜有研究。调查了厦门下潭尾湿地秋茄(Kandelia obovata)红树林恢复初期，新记录种莱氏锥滨螺(Mainwaringia leithii)种群恢复的时间动态，并分析其与植被参数的关系。研究发现，红树林恢复初期，秋茄植被生长迅速，株高、冠幅、基径和覆盖度分别由0.5年生幼林的41.3 cm、25.0 cm、1.04 cm和25%增长为8年生样地的179.2 cm、76.7 cm、5.96 cm和95%。在秋茄胚轴种植6个月左右开始记录到莱氏锥滨螺的个体，其密度和生物量在1.5 a后达到最大(分别为136个/m²和1.86 g/m²),而后逐渐降低，种植3 a后秋茄林内莱氏锥滨螺仅零星分布。除8年生的样地，莱氏锥滨...

Distribution dynamics of the Mainwaringia leithii (Gastropoda, Littorinidae) in the mangroves at early stage of rehabilitation

Arboreal gastropods comprise an important component of the mangrove benthic faunal community, and their composition and distribution patterns are affected by the characteristics of mangrove vegetation. Therefore, following the mangrove rehabilitation, the dynamic of gastropod community is strongly related to the development of vegetation. As one of the few gastropods highly associated with mangrove habitats, snail species of Mainwaringia genus belonging to the Littorinidae family are widespread in Asian mangroves. However, there are few studies on the distribution and population characteristics of Mainwaringia species in mangroves, and information of the dynamics of Mainwaringia population following mangrove rehabilitation is even scarce. In this study, we investigated the distribution and temporal dynamics of abundance of a newly recorded species, Mainwaringia leithii, in young Kandelia obovata stands in the early rehabilitation stage in Xiatanwei, Xiamen City, China. The density and abundance of M. leithii snails, and the vegetation characteristics were continuously measured since 0.5-a after plantation of K. obovata using propagules at the mudflat. The plant height, crown diameter, basal stem diameter and canopy coverage of K. obovata were 41.3 cm, 25.0 cm, 1.04 cm and 25%, respectively at the 0.5-a-old stand, and increased to 179.2 cm, 76.7 cm, 5.96 cm and 95%, respectively, at the 8-a-old stand. M. leithii individuals were found soon after the mangrove rehabilitation (i.e., 0.5 a), with respective density and biomass of 12 ind/m² and 0.29 g/m². The M. leithii population reached a maximum abundance at the 1.5-a-old stand, and their density and biomass were 136 ind/m² and 1.86 g/m², respectively. Nevertheless, the present study recorded a decrease in the abundance of M. leithii snails in the subsequent sampling campaigns, i.e., the density decreased to 61 ind/m² in the 2-a-old stand, while it was even more less, with no more than 10 ind/m² at the 8-a-old stand. The shell height of M. leithii samples collected in this study ranged from 1.90 to 8.14 mm, and 80% of the samples fell into a range between 3 mm and 7 mm. The shell height of snails presented a temporal change in association with the stand age and snail density. Small-sized M. leithii snails, with a shell height between 3-6 mm comprised a large proportion (-70%) of those collected at the 1.5-a and 2-a-old stands, wherein the snails occurred in large numbers. Contrarily, at mangrove stands with other age classes (except at the 8-a-old stand) where low snail densities were measured, the larger snails with shell height >6 mm dominated the M. leithii population. The present study found a quadratic increase in the individual weight with the shell height of snails. These results suggest that M. leithii can be a common and abundant arboreal gastropod species in the mangroves, and its recruitment occurs in rapid response to the establishment of mangrove vegetation. The temporal variation of its abundance with stand age in the early stage of rehabilitation may be partly attributed to the change in its habitat characteristics related to the development of mangrove vegetation. Regarding that the information of this species is still scarce, future studies should give more attention to the ecology of this species in mangrove forests.