既存データを活用した魚類の生息実態の解明と劣化要因の分析手法の提案

抄録

It is indicated that biodiversity in rivers have been deteriorated in recent several decades. Drastic changes of terrestrial area in rivers, such as turn into forest from sand-gravel bars, have been paid attention. In water area, however, its historical trends have not been recognized well enough to apply its results into river environment management. With these backgrounds, this research aims to recognize the historical transition of fish fauna based on the Fish Survey Part of National Census, and find factors of the deterioration of fish biodiversity. At first, 5 fish groups were set up from the viewpoints of habitat types, and regional historical transition of each group was recognized utilizing presence-absence historical pattern. Furthermore, the relationship between the decrease of each group and the historical changes of habitats was analyzed. It was found that lowering of river bed must be a factor for the decrease of specific groups. It can be said that this approach facilitates the recognition and of the deterioration of the environment of water area.