An aquatic ecoregion delineation approach based on GIS and spatial environmental data in Heihe River Basin, Northwestern China

Rapid economic growth in China has presented great challenges to its water resource managers due to a scarcity of water resources, severe water pollution, growing domestic and industrial water demands, and requirements for food security. Aquatic ecoregions are increasingly used as spatial units for aquatic ecosystem management at the watershed scale. In this paper, precipitation, drought index and elevation were selected as the regionalizing indicators for the delineation of level I aquatic ecoregions, and runoff depth, relief and vegetation coverage for the level II aquatic subecoregion delineation. A GIS method integrated with principal component analysis (PCA) and canonical correspondence analysis (CCA) was used in this study. The spatial raster overlay technology and spatial ISODATA clustering analysis approach divided the Heihe River Basin into three level I aquatic ecoregions, and eight level II aquatic subecoregions. Differences among level I and level II aquatic ecoregions in landscape-scale natural geographical attributes, climatic attributes, physical and chemical features of the river, and ecosystem attributes suggest that the aquatic ecoregions delineation is reasonable.