Factors limiting distribution and activity patterns of the soldier crab Dotilla myctiroides in Phuket, South Thailand
Factors limiting distribution and activity patterns of the soldier crab Dotilla myctiroides in Phuket, South Thailand
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DOI：
10.1007/s002270050604
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发表时间：
1999-10-01
期刊：
影响因子：
2.4
通讯作者：
Scoffin, TP
中科院分区：
文献类型：
--
作者：
Bradshaw, C;Scoffin, TP
这项研究于 1995 年 1 月至 3 月间在泰国南部普吉岛 Tang Khen 湾的潮间带沙地进行，那里的兵蟹 Dotilla myctiroides (H. Milne-Edwards) 的密度高达 120 m(-2)。在这个海湾里，长长的带状沙浪（波长40m，高度0.4m）散布着浅水池，与海岸大致平行。在白天的低潮期间，暴露在沙浪中15至20分钟后，在涨潮期间埋在沉积物表面下的螃蟹就会出现。它们随后的挖洞和进食活动导致沉积物表面产生大量沙粒。大多数螃蟹会撤退到洞穴中，有些螃蟹还会提前堵塞洞穴入口。被即将到来的潮水覆盖。蟹洞在沙浪上分布明显。每个沙波顶部的洞穴最为密集，邻近的潮汐池旁边有一片未挖出的沉积物。螃蟹在平均高水位小潮水位和平均低水位小潮水位之间最为丰富，此时表层沉积物的中值粒径类似于 2 phi。沙波以下地下水位深度和沉积物暴露时间的测量表明，在沉积物尺寸合适的情况下，控制螃蟹分布的主要因素是白天暴露的持续时间。这一观察结果与许多先前的研究相反，这些研究表明地下水位高度和沉积物排水是控制 D. myctiroides 分布的主要因素。
This study was carried out between January and March 1995 on the intertidal sand flats of Tang Khen Bay, Phuket, South Thailand, where the soldier crab Dotilla myctiroides (H. Milne-Edwards) occurs in densities of up to 120 m(-2). In this bay, long, ribbon-like sand waves (wavelength 40 m, height 0.4 m) are interspersed with shallow pools, running approximately parallel to the shore. During daylight low-tides, exposure of the sand waves is followed 15 to 20 min later by the emergence of the crabs which have been buried under the sediment surface during high tide. Their subsequent burrowing and feeding activity results in the production of large numbers of sand pellets on the sediment surface. Most crabs retreat down their burrows, and some also plug the burrow entrance, prior to. being covered by the incoming tide. The crab burrows have a distinct distribution on the sand waves. Burrows are most dense at the top of each sand wave, and a band of unburrowed sediment adjoins the adjacent tidal pools. Crabs are most abundant between mean high-water neap-tide level and mean low-water neap-tide level, where the median particle size of the surface sediment is similar to 2 phi. Measurements of water-table depth below the sand waves and the exposure time of the sediment indicated that, where sediment size is suitable, the main factor controlling crab distribution is the duration of daytime exposure. This observation is in contrast to those of many previous studies, which have suggested that water-table height and sediment drainage are the main factors controlling the distribution of D. myctiroides.