Relationships between fish and amphibian fauna and characteristic of water zone in hill-bottom valleys of upper basin of the Kokai River [Japan]
2006
Kakino, W.(Tokyo Univ. of Agriculture and Technology, Fuchu (Japan). Faculty of Agriculture) | Hujisaku, M. | Mizutani, M. | Goto, A.
Fish and amphibian species and their habitats were investigated in the thirty hill-bottom valleys located in the upper stream of the Kokai river, Tochigi prefecture. Geographically the hill-bottom valley was classified into two zones; gomen that is relatively flat along the main river, and yatsu that is paddy fields surrounded by low elevation hill, and forest. Water zones in yatsu were categorized into four components; i. e. rice paddy, pond, irrigation canal and ditch. Field survey was conducted for twenty five days from April 26th to August 25th, 2002. The results obtained were summarized as follows; 1) much difference was observed in the composition of fish and amphibian species between gomen and yatsu, 2) number of each species differed from yatsu to yatsu, 3) those yatsu which statistically showed high number of fish species had the features of large valley bottom area and, deep canal depth, and showed relatively higher number of fish species had the features of preserved water network, high rate of rice paddy area, and 4)those yatsu which showed relatively low number of amphibian species had the features of small valley bottom area, low ratio of rice paddy area and shallow canal depth.
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