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Rice fields provide important habitats for many endemic and endangered species originally dependent on wetlands as habitat. However, the value of rice fields has rarely been evaluated from a multi-scale perspective. We examined abundance of two frogs, the montane brown frog Rana ornativentris and the forest green tree frog Rhacophorus arboreus, that use rice fields as breeding sites, and explored local and landscape-level factors determining their abundance. To determine appropriate spatial scales influencing abundance, we generated different sized buffer circles around a focal rice field, calculated landscape composition in each buffer, and determined the regression model that best explained frog abundance using Akaike's Information criterion (AIC). The montane brown frog and the forest green tree frog exhibited the lowest AIC at buffer sizes of 300 and 1,000 m, respectively. Both species exhibited a higher abundance at intermediate water depths (7-10 cm). At the landscape-level, the montane brown frog showed highest abundance at intermediate forest cover (50%-60%). Forest green tree frogs showed a monotonic increase with forest cover. Because each species responded somewhat differently to spatial scale and landscape composition, context and species dependent outcomes of local restoration practices are required for particular rice fields to achieve cost-effective results.

To investigate factors involved in the recent northward invasion of the great mormon butterfly, Papilio memnon L. (Lepidoptera: Papilionidae), cold hardiness of pupae was compared among 4 populations including those in a subtropical and a northernmost area of Japan. The mean supercooling points (SCP) of diapausing and non-diapausing pupae were lower than Ϫ20°C in all populations. The SCP was not affected by an acclimation period nor by pupal weight, although it became higher with inoculation. Diapausing pupae were placed in 4 sites at different altitudes in southern Osaka Prefecture during the winter, then survival rates were compared in the spring. All individuals died at altitudes of 1,100 and 800 m, while more than half of the individuals survived the winter at 400 and 30 m. There was no difference in the survival rate at each site among populations. Even the subtropical population showed cold hardiness to survive winter in Osaka, which is located near the northern edge of the distribution of this species. These results show that the recent northward invasion has occurred without any substantial changes in the cold hardiness of this species. Based on the results, we inferred that the climatic lethal limits during the winter lie between Ϫ3.8 and Ϫ7.3°C for the minimum temperature, and between 52 and 68 frost days. We discuss the effect of climatic warming on the northward invasion of this species.

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Tokyo, Yayoi, Japan Abstract: Reintroduction of endangered or extinct species is becoming major restration activities for conservation of biodiversity and ecosystems. The crested ibis Nipponia nippon , once extinct in Japan, was released into natural environment on Sado Island, Japan, in September 2008. Since orthopteran insects are thought to be one of the major prey for the crested ibis, it is important to clarify the factors influencing the distribution and abundance of orthopterans. We investigated abundance of five orthopterans Oxya yezoensis, Atractomorpha lata, Conocephalus maculatus, Ruspolia lineosa and Teleogryllus emma on Sado Island in September 2008. Local-scale environmental factors including grass-height and land-use type arable or fallow were recorded in the field. Landscape-scale factors such as proportion of paddy fields and total length of forest edge in the buffer circle surrounding the paddy fields were extracted using GIS. Various sizes of buffer circles were generated around each paddy to identify appropriate spatial scales. Model selection was performed with a generalized linear model using the AIC to find the best model for accounting for the abundance or the probability of occurrence of these species. Landscape factors were important for all species except A. lata. The proportion of paddy fields had a significant positive effect on the abundance of O. yezoensis which was conspicuously dominant. The interaction between the proportion of paddy fields and the length of forest edge had a significant effect on C. maculatus and T. emma. At the local scale, intermediate grass-height enhanced the abundance of O. yezoensis and C. maculatus and the occurrence of R. lineosa, and fallow fields were the suitable habitats for T. emma. Our results suggest that maintaining lowland paddy fields containing fallows and reducing the frequency of mowing surrounding paddy fields are effective for increasing the orthopteran abundance and diversity in the paddy-dominated ecosystems.