JAUE2014-066 Ecosystem Assessment Method of Water Area between the Source of Urban Rivers and Upstream Area

Abstract

The multiple nature-type rivers are increasing in Japanese city in recent years and people are conscious of the preservation of the river ecosystem. However, the chemical investigation by the BOD measurement is the main method in the river investigation of the corporation in Japan, and the result of the biota investigation just find out the water quality magnitude based on the indicater species. The authors consider that the assessment of the abundant ecosystem is important to improve urban river in the future, therefore we work on the new assessment method based on the food chain. The method is focused on the food chain relations among the living organisms in Yokohama-city, and the more food chain relations among the guild (the biological community which has the same food request) are, the more complicated the relations among the creatures are; it is evaluated the abundant ecosystem. In this paper, the authors name this assessment method “the food chain complexity method”, and make case studies in Yokohama-city. In order to confirm usability of this method, we compare it with the former water quality and other evaluation.