Effects of the 26 December 2004 tsunami on littorinid molluscs near Phuket, Thailand
Effects of the 26 December 2004 tsunami on littorinid molluscs near Phuket, Thailand
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2004 年 12 月 26 日海啸对泰国普吉岛附近软体动物的影响
DOI：
10.1093/mollus/eyi071
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发表时间：
2006
影响因子：
1.2
通讯作者：
Y. Chitramvong
中科院分区：
文献类型：
--
作者：
Kitithorn Sanpanich;F. Wells;Y. Chitramvong
正在进行一项重大努力，以了解2004年12月印度洋海啸对海洋环境的影响。重点一直放在珊瑚礁上，这些珊瑚礁位于受海啸影响最严重的地区的潮下和近海。人类生命损失和人类基础设施的最大破坏发生在潮间带和潮上带区域，在这些区域，海浪破裂后具有最大的破坏力。我们试图通过使用Littorinid软体动物作为指示组来确定海啸对可能影响最大的潮间带上部地区的影响。最近公布了2002年对泰国红树林和多岩石海岸50个地点的木犀类软体动物分布的广泛调查。其中六个研究地点位于泰国普吉地区的安达曼海海岸，该地区是海啸受灾最严重的地区之一。2005年4月13日至18日，也就是海啸发生3.5个月后，对这些地点(图1)进行了重新检查，以定性地确定发生了什么破坏。在最初的调查中，在六个地点记录了13种斑潜蝇；海啸后只记录到7种。海啸并不均匀，根据当地地形的不同，对海岸线的影响也不同。研究地点包括岩石海岸和红树林地区(表1)。Kalim海滩和Nang Thong海滩的岩石海岸直接受到海啸的袭击。虽然石龙科动物的数量大幅减少，但岩石本身并未受到影响。在南通湾海滩，邻近的沙质海岸线被广泛改造(图2、3)。素林岛Mai Ngarm Bay的岩石海岸有零星的红树林(Rhizophora apulata和R.mucronata)。海岸位于海啸的背风处，没有明显的影响。Laem Mai Kaew大片红树林的一处遗址在海啸中遭受重创，事件发生后面目全非；该遗址的所有山雀都消失了。应该指出的是，该地点位于受海啸影响的红树林的海边。树木迅速驱散了海啸的力量，红树林边缘的海岸没有明显的影响。北盟滩和塔拉滩的红树林基本上没有受到海啸的影响。即使在海啸过后，在那些存在利特灵物种的地方，其密度似乎也有所下降。即使在海啸对岩石或红树林没有明显影响的地区，一些海燕也被从岩石或树木上冲走。人口减少很可能是由海啸造成的。然而，自最初在这些地点进行调查以来，已经有三年了。由于人口密度是自然变化的，人口减少可能是由于另一个原因。例如，西澳大利亚州沃特曼湾的单纹夜蛾(Noritittorina unifasciata，Gray，1826)的数量在两年内出现了显著的自然下降。海啸过后，最初在六个研究地点发现的13种菊科昆虫中只有7种存在，这一事实并不令人担忧。在珊瑚礁中发现的这种模式，在不同的地区具有不同的影响。很可能，更详细的研究将表明，该地区仍有该物种的种群，可以重新殖民受海啸影响的地区。所有的物种都是分布广泛的。已知分布范围最小的物种是2001年被描述的Bittoraria bengalensis，它是从泰国西海岸和印度已知的。所有其他物种的活动范围都要广得多。就目前所知，所有生活在泰国西海岸的金龟子都有一个浮游幼虫阶段，这将使幼虫能够在下一个产卵季节随时扩散到受影响的地区。总而言之，海啸对普吉岛地区斑潜蝇的直接影响是零星的，该地区的物种分布很可能不会发生重大的永久性变化。
A major effort is being undertaken to understand the effects of the December 2004 Indian Ocean tsunami on the marine environment. The emphasis has been on coral reefs, which are subtidal and offshore of the areas that were most heavily affected by the tsunami. The greatest losses of human life and destruction of human infrastructure occurred in the intertidal and supratidal regions where the waves had the greatest destructive force after they broke. We seek to determine the effects of the tsunami in the upper intertidal region, where the effects might be greatest, by using littorinid molluscs as an indicator group. An extensive 2002 survey of the distribution of littorinid molluscs at 50 sites in mangroves and on rocky shores in Thailand was recently published. Six of the study sites were on the Andaman Sea coast in the area of Phuket, Thailand, one of the regions most heavily hit by the tsunami. These sites (Fig. 1) were resurveyed between 13 and 18 April 2005, 3.5 months after the tsunami, to determine qualitatively what damage had occurred. Thirteen species of littorinids were recorded in the initial survey at the six sites; only seven species were recollected after the tsunami. The tsunami was not uniform, and depending on local topography affected the shorelines in different ways. The study sites included both rocky shores and mangrove areas (Table 1). Rocky shores at Kalim Beach and Nang Thong Beach were directly hit by the tsunami. While littorinid populations decreased considerably, the rocks themselves were not affected. At Nang Thong Beach the adjacent sandy shoreline was extensively modified (Figs 2, 3). The rocky shore of Mai ngarm Bay, Surin Island, has scattered mangroves (Rhizophora apiculata and R. mucronata ). The shore was in the lee of the tsunami and there were no visible effects. A site at an extensive mangrove at Laem Mai Kaew was heavily hit by the tsunami and was unrecognizable after the event; all littorinids at the site had disappeared. It should be noted that the site was at the seaward fringe of the mangrove, which was affected by the tsunami. The trees rapidly dissipated the force of the tsunami and there were no obvious effects shoreward of the mangrove fringe. Mangroves at Pak Meng Beach and Ta la Beach were largely unaffected by the tsunami. Even where littorinid species were present after the tsunami, densities appeared to have decreased. Even in areas where there were no apparent effects of the tsunami on rocks or mangroves, some of the littorinids were washed off the rocks or trees. Population reductions were likely to have been caused by the tsunami. However, it has been three years since the initial surveys were undertaken at the sites. As population densities are naturally variable, the reductions could have been due to another cause. For example, substantial natural declines in the population of Nodilittorina unifasciata (Gray, 1826) at Waterman Bay, Western Australia occurred over a two-year period. The fact that only seven of the 13 littorinid species originally found at the six study sites were present after the tsunami is not a cause for concern. The pattern found in the littorinids, as in the reefs, is of different effects in different areas. It is likely that more detailed studies would show that there are populations of the species remaining in the area that can recolonize areas affected by the tsunami. All of the species are widespread. The species with the smallest known distribution, Littoraria bengalensis, was described in 2001, and is known from the west coast of Thailand and also from India. All of the other species have much broader ranges. As far as is known, all of the littorinid species occurring on the west coast of Thailand have a planktonic larval stage, which will allow the ready dispersal of larvae into affected areas during the next spawning season. In summary, the immediate effects of the tsunami on littorinids in the Phuket area have been patchy, and it is likely there will be no major permanent changes to the distribution of species in the area.