Study on Response of Physical Phenomena to Wetland Ecosystem in Large River Mouth

1)对被列为“近危种”的Uca属植物在7个县河口滩涂的生境分布进行了野外调查。采用神经网络分析方法研究了床层材料性能与生物密度之间的关系。2)为了积累验证数值模拟的基础数据，对吉野河口的水质和浮游动物进行了观测。为了研究物理现象对湿地生态系统的响应，对二维河床变化程序和准三维水流模拟程序进行了改进，并对其准确性进行了检验。3)根据植被调查结果绘制了详细的网格化植被图。提出了两种预测植物群落分布的方法。一种是利用偏好曲线提出PHABSIM （Physical Habitat Simulation System）的概念，另一种是神经网络分析方法。4) 1999年和2000年对吉野河河口5个湿地进行了野外观测。对棘足科的分布进行了调查，并建立了分布格局预测模型。定量研究了一种常见的日本巨眼鲤科（cypodidae Macrophthalmus japonicus）对有机质的同化功能，以评价其湿地生态系统的价值。5)提出了利用主成分分析（PCA）得到的特征函数的新实用方法。它们可以成功地提取沙粒运动的时间周期性和空间路径，这对了解地形变化具有重要意义。

1) Field survey of the habitat distribution of Genus Uca that is classified "Near Threatened species" were carried out on river-mouth flats in seven prefectures. The relationship between bed material properties and inhabiting density was examined by using the neural network analysis.2) To accumulate the basic data for verifying the numerical simulation, water qualities and zooplankton were observed in the Yoshino river mouth. To investigate the response of physical phenomena to wetland ecosystems, at the same time, 2D river-bed variation program and quasi-3D flow simulation program were improved and examined their accuracy.3) A detailed meshed vegetation map is presented based on the results of a full vegetation survey. Two methods to predict plant community distribution were proposed. One is a method using the preference curve developed the concept of PHABSIM (Physical Habitat Simulation System) and the other is the neural network analysis.4) Field observations were carried out in five wetlands in the Yoshino river estuary during 1999 and 2000. The distribution of Ocypodidae was investigated and a distribution pattern prediction model was developed. The assimilation function of organic matter by a common Ocypodidae Macrophthalmus japonicus was examined quantitatively to evaluate one of the wetland ecosystems worth.5) New practical methods to utilize the eigen functions obtained by Principal Component Analysis (PCA) were proposed. They can be succeeded to extract the temporal periodicity and the spatial path of sand movement, which are important for understanding the topography change.