Evaluation of physical and ecological environments of a coral reef and its conservation strategy in a regional environmental system

1)对石垣县Fukido和Todoroki河口地区的珊瑚礁、海草床、潮滩和红树林组成的综合生态系统进行了野外调查，明确了洋流、相关热物质运输、珊瑚群落代谢等特征。2)建立了新的珊瑚和海草床冠层光学模型，结合非线性逆估计方法，用于遥感图像分析。利用这些模型，我们已经成功地对珊瑚和海草床冠层的高度和密度进行了高精度的估计，并在水深测绘中取得了成功。我们进一步开发了一种遥感方法来检测沉积红壤对珊瑚礁的覆盖。3)通过对石垣岛、伊洛莫特岛和二者之间的关成礁湖近20年的20多幅LANDSAT影像的分析，发现了陆地区域土地利用和植被覆盖的历史变化及其与生境特征年际变化的关系。4)利用装有GPS记录仪和手机的小型漂浮器进行近地表颗粒跟踪，利用高频雷达探测海洋表面流的空间分布，以及在广泛区域内不同地点的浮游生物网，揭示了珊瑚幼虫从喀喇玛群岛向冲绳主岛西海岸扩散的珊瑚礁间连通性。本文利用JCOPE模型的计算结果，建立了一种多巢沿海海洋模型，分析了琉球群岛沿海地区的流动结构和幼虫的运输过程。利用这一数值模拟模式，我们成功地再现了从喀喇玛群岛到冲绳主岛西海岸的东流及其相关的幼虫运输，并阐明了东流产生的物理机制。5)为了阐明最近在琉球群岛爆发的棘棘海星（crowof -thorns starfish， COTS）的种群动态，我们成功地开发了基于分子技术和遗传标记的野生棘棘海星幼虫鉴定系统。我们还发现了在琉球群岛五个不同珊瑚礁取样的COTS产卵高峰期及其对当地水温的依赖。少

1)Performing field surveys for integrated ecosystems comprised of coral reef, seagrass bed, tidal flat and mangroves at Fukido and Todoroki river mouth areas in Ishigaki Is, we have clarified characteristics of currents, related thermal and material transport, coral community metabolism and others. 2)We have developed new optical models for coral and seagrass bed canopies, combined with a nonlinear inverse estimation method, for remote sensing image analyses. With these models, we have succeeded in high-accuracy estimation of coral and seagrass bed canopy height and density and in bathymetry mapping. We have further developed a remote sensing method to detect the coverage of coral reefs by deposited red-soil. 3)Analyzing more than 20 LANDSAT images in the past 20 years at Ishigaki and Iriomote Islands and Sekisei Lagoon in between them, we have found historical change of land-use and vegetation cover of the land areas and its relationship with the inter-annual change of habitat charact … More eristics in the neighboring coral reefs like coral coverage. 4)With a comprehensive field in which we did near-surface particle tracking using small drifters installed with a GPS logger and a mobile phone, HF-radar measurement to detect spatial distribution of ocean surface current, plankton netting at various locations in the wide area concerned, we revealed the inter-reef connectivity in terms of coral larvae dispersal from the Kerama Islands to the west coast of main Okinawa Island. We have developed a multiple-nesting coastal ocean model, in which the computational results of JCOPE model are assimilated, to analyze the flow structure in the coastal areas of the Ryukyu Islands and the larval transport process. With this numerical simulation model we have succeeded in reproducing the eastward current and associated larval transport from the Kerama Islands to the west coast of main Okinawa Island and clarifying the physical mechanism of the generation of the eastward current. We have applied the numerical model further, revealing the inter-reef connectivity in wider regions covering the Ryukyu Islands. 5)To elucidate population dynamics of crow-of-thorns starfish(COTS), which has recently shown outbreaks in the Ryukyu Islands, we have succeeded in developing a larval identification system for wild COTS larvae based on molecular techniques and genetic markers. We have also found peak spawning periods of COTS sampled at five different reefs in the Ryukyu Islands and their dependence on the local water temperature. Less