Published papers

The Daurian Redstart Phoenicurus auroreus has expanded its breeding distribution in recent years and now breeds in Japan, previously only part of its wintering range. We analyzed the breeding habitat selection of the population at the nest and territory scale in the Kirigamine Highlands, Nagano, Central Japan. At the nesting scale, the birds chose buildings frequently occupied by humans, while at the territory scale, they avoided sites in larger built-up areas. Our findings demonstrate that the breeding habitat selection of Daurian Redstart is influenced by environmental factors at both nest and territory scales.

We determined breeding-site selection of Northern Goshawks (Accipiter gentilis) by comparing 33 breeding sites to 40 nonbreeding sites at the small (nest tree and vegetation structure within an 11.3-m radius of the nest) and the large scale (biomass of prey species and landscape structure within a 500-m radius from the nest) in the urbanized area of Kanagawa Prefecture, Japan. Goshawks selected primarily Japanese cedar (Cryptomeria japonica) trees over 50-cm diameter at breast height (DBH) as nest trees. Trees smaller than 35-cm DBH were avoided. We used univariate logistic regression to assess vegetation structure of the nesting area. At the small scale, canopy trees in the nest plots were larger and taller, with more canopy cover, than those in non-nesting plots, and nests were farther from human habitations. In addition, nest plots had fewer understory trees than non-nest plots. In multivariate logistic regression, the DBH of canopy trees, number of understory trees, and distance to human habitation were highest in importance. At the large scale, nest plots had a greater percentage of forest area, smaller percentage of built area, more forest edge facing open land, and more forest edge facing PCDRS (parks, cemeteries, developed land, recreational fields, and small-scale vegetated areas <0.01 km(2) in a matrix of >= 30% residential areas). In the multivariate model, the length of forest edge facing open land and the percentage of built area were of highest importance.

We analyzed changes in land use from 1963 to 2000 in the northern part of Awaji Island in central Japan, using topographical maps and aerial photographs. We compared these changes between two different irrigation systems: tazu, in which a community group jointly owns the rights to a water source, and private management. The study area consisted of 57.3% paddy field, 22.2% woodland, 7.2% urban land use, 6.3% grassland, 5.8% water body, and 1.2% dry field in 1963. In 2000, the area consisted of 44.3% paddy field, 21.0% woodland, 12.6% urban land use, 11.6% grassland, 5.3% water body, and 5.0% dry field. The proportion of agricultural use had decreased markedly over the 37-year period. In the tazu area, 38.1 and 37.7% of former paddy field had changed into urban land use and grassland, respectively, and 19.3% of former paddy field had become dry field by 2000. In contrast, 30.6% of former rice paddy had become dry field in the private management area. About half of the former rice paddy had changed into grassland (26.3%) and urban land use (24.0%) in the private area, and 18.6% had become woodland in 2000. In the tazu area, there were fewer abandoned fields, because farmers still manage their fields according to strict regulations. In the private management area, the set-aside or abandoned fields had changed into woodlands as a result of vegetation succession, because farmers had abandoned fields located far from their homes or on steep slopes. These results suggest that the irrigation system may influence the pattern of change in land use. © 2007 International Consortium of Landscape and Ecological Engineering and Springer.

A magnitude 9.0 earthquake struck off northeastern Japan on 11 March 2011. The subsequent tsunami wrought destruction on a massive scale. Kesennuma City was one of the most heavily damaged regions in Miyagi Prefecture, where more than 1000 people were killed by the tsunami and resulting fire; 215 people are still missing. Here we analyzed historical landuse changes in the tsunami-affected area of Kesennuma city center, Miyagi Prefecture, using topographic maps from 1913 and 1952 and vegetation maps from 1979 and 2011. The area consisted of 7.3% urban land use, 10.5% dry field, 55.5% rice paddy field, 4.7% wetland, 0.3% grassland, 5.3% forest, and 16.3% water body in 1913 and 76.1% urban land use, 1.7% dry field, 17.9% rice paddy field, 0.9% wetland, 1.6% forest, and 1.6% water body in 2011. During the period, the area of urban land use increased more than 10-fold, while that of rice paddy field sharply decreased from 55.5% to 17.9%. The 77 Bank estimated that the total economic damage in Kesennuma City was 232.4 billion yen, representing annual production value of all companies located in the damaged area. Our calculations for urban land use, dry field, and rice paddy field showed losses of 112.7 billion yen and 69 million yen due to the tsunami in the areas of urban and agricultural land use, respectively.

In this article, we examined the value of the traditional Japanese flood control measure that uses a discontinuous levee (kasumitei). By avoiding the use of flood-prone lowlands for inhabitation and allowing floodwater movement through the kasumitei, the cost of building damage can be reduced, and water supply to wetlands can be increased. The purpose of our study was to quantify flood damage cost reductions and the potential gains for wetland species as part of an ecosystem-based disaster reduction initiative. The study was conducted in the Amano River basin in central Japan. First, we applied a drainage model and calculated the flood damage cost reduction in the floodplain from an evaluation of inundation depth differences. As part of an analysis of potential wetness, we identified areas where 1 m of flooding was predicted in rice paddies near kasumitei. We also quantified a topographic wetness index, the ratio of lowlands, and the ratio of poorly drained soil types, all of which would be beneficial to wetland species. We also investigated land-use change in the area and the relevant financial support framework. The results showed that a simulated closed levee system causes greater inundation and exposure to residents, and the value of paddy areas near kasumitei was calculated to be 43,830 JPY/1000 m2/year at the maximum. Even though the paddies tend to be poorly drained, these areas have been continuously used as paddies for the past century even under development pressure. The economic value and habitat potential of kasumitei levee systems have not been considered as part of any previous flood-management policies. We propose these existing flood control areas to be considered in the financial support framework in the context of river basin and ecosystem-based disaster risk reduction management.