抄録
In Japan, many restoration projects and efforts to conserve the river environment were carried out across the country. In spite of these efforts, effective measures to conserve the river ecosystem or post-evaluation of the restoration project were insufficient due to a lack of environmental indicators. We established biological indicators using fish fauna in the midstream segment-based ecoregions of the northwest ecoregions based on the concept that quality of biota can be compared in the same segment-based ecoregion. Furthermore, multiple regression analysis was carried out to explain the relationship between the index value and the physical characteristic of a habitat. As a result of the multiple regression analysis, it was found that embayment increased the number of fish species. On the other hand, weir and ponding decreased it. Establishing biological indicators using the ecoregion concept enabled to compare the integrity of fish fauna between watersheds, which had been previously difficult to examine.
