Author(s): Mikyoung Choi; Yasuhiro Takemon; Tetsuya Sumi
Linked Author(s): Tetsuya Sumi
Keywords: Fluvial geomorphology; Landscape; Habitat richness; Sandy bar; Historical change; Kizu River
Abstract: Hierarchical structure of aquatic habitats in the lower reaches of the Kizu River, a tributary of the Yodo River, central Japan, was investigated using images of aerial photographs taken in 1948, mid-1970s and 2009. The channel landscapes into water surface, island bar and lateral bar as channel scale characteristics. Bar scale landscapes into bareland, bushland, woodland and cleared-land for artificial land use. And then, aquatic habitats were classified into riffle, run and deep slow, active pool, terrace pool, bar-head backwater and bar-tail backwater. Historical changes in the habitat structure were analyzed quantitatively using the DEM data and the aerial photographs. Results of the landscape changes showed that bar area and shoreline index in the channel scale increased with decreasing water surface, and at the same time, bareland decreased with increasing bushland and woodland. The significant increase of habitat richness during the period indicated that the increase of vegetation area contributed to raising habitat richness to some extent. Therefore, the stability of flow regimes and reduction in sediment dynamics fascinated the environmental heterogenety in there 60 years in the Kizu River.