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We elected an area where uniform paddy cultivation is done by the overall community, and divided roughly into five rice field types; Ⅰ(Rice field and lotus field mixture area), Ⅱ(Pond adjoining area), Ⅲ(Rotation of crops area of rice, wheat and soybean), Ⅳ(Fabricated field / Mixture of the waterway of the ground and concrete) and Ⅴ(Not-fabricated field / Mixture of the waterway of the ground and concrete) in Noubi plains. We conducted a line census investigation on a ridge in order to investigate the species composition of frogs according to the rice field type. The results of our survey, there were large numbers of frogs in the areas which have a moist cultivating environment (TypeⅠ, Ⅴ). In contrast, in the well-drained rice fields (TypeⅡ, Ⅲ and Ⅳ) where rice seedlings were transplanted in June, there were small numbers of frogs irrespective of the environmental structure. The number of frogs in Type Ⅰ where different crops (rice and lotus) were cultivated in parallel was larger than that in Type Ⅴ because the waterside has always existed there.

Tokyo salamander (Hynobius tokyoensis) indigenous in the Miura peninsula, is threatened with extirpation due to habitat loss from development. Artificial breeding sites in running water were introduced; however, many of the sites are not considered to be high quality breeding habitat. This species normally deposits its egg-sacs in still water, attached to a suitable twig, leaf or grass stem. We studied the retention of egg-sacs at two different types of running water sites. Our study showed that 48.7% of egg-sacs were washed away at natural stream sites, and 76.8% of egg-sacs were washed away by small streams created by erosion at abandoned rice paddy sites. We created still water sites in the abandoned rice paddies, and the results showed that only 5.3% of the egg-sacs were washed away. For conservation of this species, it may be necessary to protect a wide variety of riparian zones, groundwater systems, and forested areas.

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