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了普查后，沿水道设置了一条样线，并选择了6个站点，从红树林的泥滩到陆缘进行了详细的采样。所有站点的沉积物都是由沙和粉质粘土组成的，比例大致相同。林内沉积物中有机质含量高于滩涂。2.采用定性和定量相结合的方法研究底栖动物。在外滩和移栽区，环足蟹、双壳类和多毛类蠕虫是主要成分。在森林中心地带，腹足类、多毛类、环足类和芝麻蟹占主导地位。在定量样本中，共有63种，平均密度为578只/m~2，物种丰富度和个体数总体上呈现由滩涂向林内递减的趋势。而多样性指数则表现出相反的趋势。4.我们原计划研究底栖动物废弃红树林沼泽的再定殖化过程。然而，我们目前找不到合适的地方进行这样的研究。5.为了对一些重要的经济动物进行种群研究，我们选择了一只雏鸟(Anadara)。为了进行雏鸟的监测工作，我们在设置6个月后从养殖箱中采集了雏鸟。在泥滩上，贝类仍然活着，但它们的密度很低。为了研究藤壶的定殖过程，我们收集了藤壶在几种不同环境中栖息的塑料杆。

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.