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Nishi-Tokyo-shi, Japan

Sugawara H.,Japan National Defense Academy | Shimizu S.,Tokyo Metroplitan University | Takahashi H.,Tokyo Metroplitan University | Hagiwara S.,Institute for Nature Study | And 3 more authors.
Journal of Environmental Quality | Year: 2016

City-scale warming is becoming a serious problem in terms of human health. Urban green spaces are expected to act as a countermeasure for urban warming, and therefore better understanding of the micro-climate benefits of urban green is needed. This study quantified the thermal influence of a large green park in Tokyo, Japan on the surrounding urban area by collecting long-term measurements. Apparent variations in the temperature difference between the park and surrounding town were found at both the diurnal and seasonal scales. Advection by regional-scale wind and turbulent mixing transfers colder air from the park to urban areas in its vicinity. The extent of the park's thermal influence on the town was greater on the downwind side of the park (450 m) than on the upwind side (65 m). The extent was also greater in an area where the terrain slopes down toward the town. Even on calm nights, the extent of the thermal influence extended by the park breeze to an average of 200 m from the park boundary. The park breeze was characterized by its divergent flow in a horizontal plane, which was found to develop well in calm conditions late at night (regional scale wind <1.5 m s-1 and after 02:00 LST). The average magnitude of the cooling effect of the park breeze was estimated at 39 Wm-2. This green space tempered the hot summer nights on a city block scale. These findings can help urban planners in designing a heatadapted city. © American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. 5585 Guilford Rd., Madison, WI 53711 USA. Source


Hamao S.,Institute for Nature Study | Watanabe M.,Teikyo University | Mori Y.,Teikyo University
Ethology Ecology and Evolution | Year: 2011

Since ambient noise interferes with sound transmission, urban noise can affect the acoustic structure of birdsong. Previous studies have examined song features (e.g. high minimum frequency) in urbanised areas; however, these studies did not exclude the effects of other factors. For example, the intensity of male-male competition is known to affect song structure. In 22 urban parks in Tokyo, Japan, we measured the effects of noise level and male density, an indicator of the intensity of competition among males, and examined the relationship between these factors (noise and male density) and song structure of the great tit, Parus major. We found that males in noisier parks sang songs with higher minimum frequencies, more phrases and longer durations. The frequency shift appeared to mitigate the acoustic masking of songs by low-frequency background noise, as has been shown in previous studies. Songs with repeated phrases and of longer duration are likely to be more detectable for receivers under noisy conditions. In addition, we found that male density tended to affect the minimum frequency and the number of phrases in, but not the lengths of, their songs. Overall, both noise and male density affected the song structure of great tits in urban habitats. © 2011 Dipartimento di Biologia Evoluzionistica dell'Università, Firenze, Italia. Source


Hamao S.,Institute for Nature Study
Animal Behaviour | Year: 2011

Avian brood parasitism reduces the reproductive success of hosts. Thus, hosts have evolved antiparasite strategies such as rejection of parasitic eggs and aggressive nest defence against brood parasites. Japanese bush warblers, Cettia diphone, do not reject the parasitic eggs of little cuckoos, Cuculus poliocephalus, because their eggs mimic warblers' eggs. To examine whether Japanese bush warblers show nest defence behaviour against their parasite, I investigated the responses of the warblers to a little cuckoo dummy. Japanese bush warblers are residents, while little cuckoos are summer visitors; thus, the warblers start breeding earlier than the cuckoos. Accordingly, the risk of being parasitized increases as the season progresses. Therefore, I also examined whether the intensity of nest defence differed before and after cuckoo arrival. Japanese bush warblers showed remarkably aggressive responses to the cuckoo dummy, and levels of aggression were higher after the cuckoo arrived. These results suggest that Japanese bush warblers adaptively adjust their nest defence behaviour in response to increased risk of being parasitized. This study indicates that differences in migratory habits between hosts and brood parasites produce seasonal changes in antiparasite behaviour. © 2011 The Association for the Study of Animal Behaviour. Source


Okahisa Y.,Rikkyo University | Morimoto G.,Rikkyo University | Morimoto G.,Toho University | Morimoto G.,Institute for Nature Study | Takagi K.,Japan Bird Research Association
Ornithological Science | Year: 2012

Although Narcissus Flycatchers readily use nest boxes, natural nest sites and nest characteristics have not previously been described. The location of 41 Narcissus Flycatcher nests and data on the dimensions of 17 nest holes in the Fuji Primitive Forest of Japan are described. Japanese Hemlocks were the most commonly chosen tree species for nesting although 14 other tree species were also used and no significant nest tree species preference was observed. Nests (classified as either half cavity, full cavity, chimney, or shelf), were built at an average height of 7.3 m. Flycatchers tended to nest in dead trees or trees with trunks greater than 20 cm in diameter (mean 30.9 cm). Nests were typically made from dead leaves, moss, plant fibers, and animal hair. This is the first description of natural nest sites and nest characteristics of Narcissus Flycatchers; details are compared with those of other closely related flycatcher species. © The Ornithological Society of Japan 2012. Source


Sawabe K.,Japan National Institute of Infectious Diseases | Isawa H.,Japan National Institute of Infectious Diseases | Hoshino K.,Japan National Institute of Infectious Diseases | Sasaki T.,Japan National Institute of Infectious Diseases | And 9 more authors.
Journal of Medical Entomology | Year: 2010

To evaluate the vectorial capacity of mosquitoes for viruses in Japan, the host-feeding habits of the mosquitoes were analyzed by sequencing polymerase chain reaction-amplified fragments of the cytochrome b and 16S ribosomal RNA regions of the mitochondrial DNA of 516 mosquitoes of 15 species from seven genera that were collected from residential areas during 20032006. Culex pipiens L. and Aedes albopictus Skuse were the most commonly collected species in urban and suburban residential areas. Anautogenous Culex pipiens pallens Coquillett was distinguished from the autogenous Cx. pipiens form molestus Forskal using a polymerase chain reaction-based identification method. Both Cx. p. pollens and Cx. p. form molestus exhibited similar host-feeding habits, broadly preferring avian (50.0 and 42.5% of avian, respectively) and mammalian (38.6 and 45.0% of avian, respectively) hosts, such as tree sparrows, ducks, and humans. Conversely, Ae. albopictus exhibited a highly mammalophilic and anthropophilic feeding pattern, with 84.2% feeding on mammalian hosts and 68.5% of these on humans. We concluded that in Japan, Cx. pipiens might play a significant role in the avian-to-mammal transmission of viruses, such as West Nile virus, whereas Ae. albopictus might play a role in the human-human transmission of dengue and Chikungunya viruses. © 2010 Entomological Society of America. Source

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