Fundametal Reseach for the Preservation of Coral Reefs

1.1997年5月在濑子岛周围的10个研究区设置了20-40个平板，与1995年和1996年相同。在9月（放置后3个月）收集这些平板，并对每个平板中的物种数和个体数进行计数。其中以鹿角珊瑚属的种类最多，占总数的95%以上，柱珊瑚属和小珊瑚属等小珊瑚属的种类也较多。很少观察到Porites的少年。这项监测从1989年开始已持续了9年。1996年观测到最密集的沉降，10，000 - 30，000/m^2，这是正常密度的10倍。2.在不同的调查区域对两种优势种鹿角珊瑚Acropora hyacinthus和指状鹿角珊瑚A.digitifera的种群结构进行了研究和分析。各恢复区种群的主要年级大小不同。这一事实似乎暗示，多年的主导口角， ...更多信息 3.研究海胆属海胆与幼珊瑚密度的关系，分析海胆的摄食效应。1996年，幼珊瑚密度与海胆密度之间呈凸型关系。1997年的研究结果与此相反，即在海胆密度低和海胆密度高的情况下，幼年珊瑚的密度都较高。4.利用围隔（无海星星星区）和围隔（海星星星区）的珊瑚群落，研究了浮游植物对风信子种群结构的捕食作用。1996年围隔（海星星星区）周围的海星星星攻击较为强烈，使围隔区的密度和种群结构发生了突然的变化。但在围隔中观察到种群的连续结构，其他实验结果正在分析中。少

1.I set 20-40 plates at 10 study areas around Sesoko Island in May, 1997 as same as 1995 and 1996. These plates were collected in September (3 months after setting), and the number of species and the number of individuals were counted in each plate. The most abundant species belong to the genus Acropora occupied over 95% of the total, subordinally species of Pocilloporide, such as Stylophora and pocillopora, were abundant. Juveniles of Porites were rarely observed. This monitoring has been continued from 1989 for 9 years. The most dense settlement, 10,000-30,000/m^2 was observed in 1996 and this was caten times of the normal density. However, the density of settlement returned to the normal density.2.The population structure of the two dominant species, Acropora hyacinthus and A.digitifera, were studied and analyzed in several areas. The size of main year class of the populations in recoveing areas were different each other. This fact seems to implicate that the years of dominant spats … More set were different each other.3.The relationship between the sea urchins, genus Echinometra, and the density of juvenile corals was studied for analyzing the grazing effect of the sea urchin. The convex relationship was seen between the density of juvenile corals and the density of sea urchin in 1996. However, opposite result, i.e.a concave relationship was observed in 1997, namely the density of juvenile corals was high both at low density and high density of the sea urchin.4.The predation effect of Acanthaster planci on the population structure of A.hyacinthus was studied using the coral communities both in an enclosure (sea star free) and in the surrounding area (sea star area). Attack of the sea star was intensive around the enclosure (sea star area) in 1996, so that the density and the population structure were suddenly changed in the surrounding area. However, the continuous strucure was observed on the population in the enclosure.The results of other experiments are analyzing now. Less