Benthic communities and biodiversity in Thai mangrove swamps

1.实地研究在泰国Samut Songkhram省的Klong Kone红树林沼泽地进行。在对红树林沼泽地进行全面调查后，我们沿着水道设置了样线，从泥滩到红树林向陆边缘选择了6个站点进行详细采样。沉积物由砂和粉质粘土组成，在所有站点的比例大致相同。森林内沉积物中有机质含量高于泥滩。2.对底栖动物进行了定量和定性采样。外滩涂和移植区以蟹类、双壳类和多毛类蠕虫为主。在森林的中部，腹足类，多毛类，Cypodid和sesarmid蟹是突出的。3.在定量取样中，共发现63种钉螺，平均密度为578只/m^2。物种丰富度和个体数从滩涂向林内呈下降趋势。4.本研究拟对废弃红树林沼泽底栖动物的降解过程进行研究。然而，我们无法找到合适的地方，这样的研究在这个时候。5.对于一些重要的经济动物的种群研究，我们选择了一个海扇（Anadara）。为了进行蛤蚌的监测工作，我们在养殖笼设置后6个月从养殖笼中收集蛤蚌。在泥滩中，蛤蚌仍然活着，但密度很低。为了研究藤壶的定殖过程，我们收集了几种不同环境中藤壶的塑料杆，并在其上进行了定殖。

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.