Benthic communities and biodiversity in Thai mangrove swamps

1.在泰国Samut Songkhram省的Klong Kone红树林沼泽进行了实地研究。在对红树林沼泽进行全面调查后，我们沿着水道设置了样线，并选择了6个站点，从泥滩到红树林的陆地边缘进行详细采样。沉积物由砂和粉质粘土组成，在所有站点的比例大致相同。森林内沉积物有机质含量高于泥地。通过定量和定性取样对底栖动物区系进行了研究。外泥滩和移栽区以半足蟹、双壳类和多毛类蠕虫为主。在森林中部，腹足类、多毛类、尾足类和芝麻蟹类居多。在森林向陆地的边缘，有大量的厌食蜗牛。在定量样本中，共发现63种，平均密度为578只/ m^2。从泥滩到林内，物种丰富度和个体数都有减少的趋势。多样性指数则呈现相反的趋势。我们计划研究底栖动物对废弃红树林沼泽的再定殖过程。然而，我们目前找不到合适的地方进行这样的研究。对于一些经济上重要的动物的种群研究，我们选择了一种鸟蛤（Anadara）。为了进行贝的监测工作，我们在设置6个月后从培养笼中收集贝。在泥滩上，仍有鸟蛤存活，但密度较低。然而，对于森林里的站点来说，大多数鸟都死了。为了研究藤壶的定植过程，我们在几个不同的环境中收集了藤壶定居的塑料杆。

1.Field studies were conducted at Klong Kone mangrove swamps in Samut Songkhram Province, Thailand. Following a general survey of the mangrove swamps, we set a transect line along a water channel and selected 6 stations for detailed samplings from mud flat to landward fringe of the mangrove forest. The sediments were composed of sand and silt-clay roughly in the same proportions at all the stations. Organic matters in the sediments inside the forest were higher than those in the mud flat.2.We studied the benthic fauna by quantitative and qualitative samplings. In the outer mud flat and the transplanted area, ocypodid crab, bivalves and polychaete worms were major components. In the central parts of the forest, gastropods, polychaetes, ocypodid and sesarmid crabs were prominent. In the landward fringe of the forest, erobid snails were abundant.3.In the quantitative samples, we found a total of 63 species and an average density of 578 individuals per m^2. There was a general tendency for both species richness and number of individuals to decrease from mud flat to the inner part of the forest. However diversity index showed the opposite trend.4.We had planned to study recolonization process of the discarded mangrove swamps by benthic animals. However, we could not find appropriate places for such a study at this time.5.For population studies of some economically important animals, we have selected a cockle (Anadara). For the monitoring work of cockles, we collected the cockles from the culture cages 6 months after set-up. In the mud flat, cockles were still alive but their density was low. For the stations in the forest, however, most of the cockles had died.For the studies of colonization processes of the barnacles, we collected plastic poles to which barnacles had settled at several different environments.