報告書番号

Y02011

タイトル（和文）

ＧＩＳを活用した生態系解析・評価とアセスメントへの応用

タイトル（英文）

The ecosystem analysis and evaluation by using geographic information systems and their application to the environmental Impact assessment

概要 （図表や脚注は「報告書全文」に掲載しております）

「新・生物多様性国家戦略」の策定、「環境影響評価法」で生態系評価項目の追加等、生態系保全に向けた具体的施策が推進されている。また地理情報システム（ＧＩＳ）を活用した自然環境の解析・評価が可能となってきた。しかし、生態系に関しては具体的な解析・評価手法および環境アセスメントに適用した場合の有効性については明らかではない。そこで本研究では、地図や電子データ等の既存資料をベースとしてＧＩＳを活用した生態系解析・評価手法を開発するとともに、発電所立地等の環境アセスメントへ適用した場合の有効性について明らかにすることを目的とした。その結果、ＧＩＳのデータ形式として代表的なメッシュデータとラインで囲まれたポリゴン（面）データの２つの方法で生態系を解析・評価する手法を開発した。さらに環境アセスメントにＧＩＳを活用した解析・評価手法を適用し、その有効性を明らかにした。

概要 （英文）

The purpose of this study is to develop a method of analyzing and evaluating an ecosystem utilizing GIS-related maps and electronic data, and to further clarify the effectiveness of this method when it is applied to environmental impact assessments for the construction of power generation plants and suchlike.We have developed a method of analyzing and evaluating an ecosystem using two typical forms of GIS data: one is mesh data and the other is polygon or line coverage data.In the analysis and evaluation based on mesh data, we have developed a method of using geographic mesh data for topography and soil (which is based on thematic maps and meteorological data), and biological mesh data for animals and vegetation (which is based on data published on the Ministry of the Environment’s website). In this method, meshes are classified by type of natural environment and the current state of the ecosystem. Comprehensive evaluation is then conducted by calculating indexes of animal diversity, the degree of natural vegetation, and topographic diversity (three factors which have been established as indicators for evaluating an ecosystem).In the analysis and evaluation based on polygon data, we have developed a method that utilizes a basic environmental typology map (ecotope map). The map is created by overlaying polygon maps drawn from GIS data (such as the landform classification map, soil classification map and physiognomic vegetation map). Due to the differences in the precision of each polygon map, a simple overlay operation causes a lot of small, ecologically meaningless polygons. We therefore developed a program to automatically adjust the polygon maps through calculation of the degree of uneven distribution and discriminant analysis. Ecological evaluation of each ecotope is conducted by calculating the diversity index based on the number of species and the greenery occupancy rate obtained from the vegetation survey sheets.The Ministry of the Environment states that grasping the impact of a project on the basic environment and selecting notable species and communities are important procedures in the scoping stage of ecological assessments based on the existing data. We applied our GIS analysis and evaluation method and clarified its effectiveness.We were able to classify the impact on the basic environment according to the degree of seriousness by overlaying the proposed project area with the ecotope map. Regarding the selection of notable species and communities, we succeeded in selecting notable species in terms of dominance, typicality and distinctiveness based on their inhabiting area shown on the ecotope map overlaid with the data for the points where each animal species was observed. These results demonstrated that environmental analysis and evaluation using GIS is effective.

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